document_title: AC motor

question_text: who produced the first motor that ran on ac

question_tokens: who produced the first motor that ran on ac

text: AC motor

text: Operating principles[edit]

text: The two main types of AC motors are induction motors and synchronous motors. The induction motor (or asynchronous motor) always relies on a small difference in speed between the stator rotating magnetic field and the rotor shaft speed called slip to induce rotor current in the rotor AC winding. As a result, the induction motor cannot produce torque near synchronous speed where induction (or slip) is irrelevant or ceases to exist. In contrast, the synchronous motor does not rely on slip-induction for operation and uses either permanent magnets, salient poles (having projecting magnetic poles), or an independently excited rotor winding. The synchronous motor produces its rated torque at exactly synchronous speed. The brushless wound-rotor doubly fed synchronous motor system has an independently excited rotor winding that does not rely on the principles of slip-induction of current. The brushless wound-rotor doubly fed motor is a synchronous motor that can function exactly at the supply frequency or sub to super multiple of the supply frequency.

text: Other types of motors include eddy current motors, and AC and DC mechanically commutated machines in which speed is dependent on voltage and winding connection.

text: History[edit]

text: Alternating current technology was rooted in Michael Faraday's and Joseph Henry's 1830–31 discovery that a changing magnetic field can induce an electric current in a circuit. Faraday is usually given credit for this discovery since he published his findings first.[1]

text: In 1832, French instrument maker Hippolyte Pixii generated a crude form of alternating current when he designed and built the first alternator. It consisted of a revolving horseshoe magnet passing over two wound wire coils.[2]

text: Because of AC's advantages in long distance high voltage transmission, there were many inventors in the United States and Europe during the late 19th century trying to develop workable AC motors.[3] The first person to conceive of a rotating magnetic field was Walter Baily, who gave a workable demonstration of his battery-operated polyphase motor aided by a commutator on June 28, 1879, to the Physical Society of London.[4] Describing an apparatus nearly identical to Baily's, French electrical engineer Marcel Deprez published a paper in 1880 that identified the rotating magnetic field principle and that of a two-phase AC system of currents to produce it.[5] Never practically demonstrated, the design was flawed, as one of the two currents was “furnished by the machine itself.”[4] In 1886, English engineer Elihu Thomson built an AC motor by expanding upon the induction-repulsion principle and his wattmeter.[6] In 1887, American inventor Charles Schenk Bradley was the first to patent a two-phase AC power transmission with four wires.

text: "Commutatorless" alternating current induction motors seem to have been independently invented by Galileo Ferraris and Nikola Tesla. Ferraris demonstrated a working model of his single-phase induction motor in 1885, and Tesla built his working two-phase induction motor in 1887 and demonstrated it at the American Institute of Electrical Engineers in 1888[7][8][9] (although Tesla claimed that he conceived the rotating magnetic field in 1882).[10] In 1888, Ferraris published his research to the Royal Academy of Sciences in Turin, where he detailed the foundations of motor operation;[11] Tesla, in the same year, was granted a United States patent for his own motor.[12] Working from Ferraris's experiments, Mikhail Dolivo-Dobrovolsky introduced the first three-phase induction motor in 1890, a much more capable design that became the prototype used in Europe and the U.S.[13][14][15] He also invented the first three-phase generator and transformer and combined them into the first complete AC three-phase system in 1891.[16] The three-phase motor design was also worked on by the Swiss engineer Charles Eugene Lancelot Brown,[13] and other three-phase AC systems were developed by German technician Friedrich August Haselwander and Swedish engineer Jonas Wenström.[17]

text: Induction motor[edit]

text: Slip[edit]

text: If the rotor of a squirrel cage motor were to run at the true synchronous speed, the flux in the rotor at any given place on the rotor would not change, and no current would be created in the squirrel cage. For this reason, ordinary squirrel-cage motors run at some tens of RPM slower than synchronous speed. Because the rotating field (or equivalent pulsating field) effectively rotates faster than the rotor, it could be said to slip past the surface of the rotor. The difference between synchronous speed and actual speed is called slip, and loading the motor increases the amount of slip as the motor slows down slightly. Even with no load, internal mechanical losses prevent the slip from being zero.

text: The speed of the AC motor is determined primarily by the frequency of the AC supply and the number of poles in the stator winding, according to the relation:

text: where

text: Actual RPM for an induction motor will be less than this calculated synchronous speed by an amount known as slip, that increases with the torque produced. With no load, the speed will be very close to synchronous. When loaded, standard motors have between 2–3% slip, special motors may have up to 7% slip, and a class of motors known as torque motors are rated to operate at 100% slip (0 RPM/full stall).

text: The slip of the AC motor is calculated by:

text: where

text: As an example, a typical four-pole motor running on 60 Hz might have a nameplate rating of 1725 RPM at full load, while its calculated speed is 1800 RPM. The speed in this type of motor has traditionally been altered by having additional sets of coils or poles in the motor that can be switched on and off to change the speed of magnetic field rotation. However, developments in power electronics mean that the frequency of the power supply can also now be varied to provide a smoother control of the motor speed.

text: This kind of rotor is the basic hardware for induction regulators, which is an exception of the use of rotating magnetic field as pure electrical (not electromechanical) application.

text: Polyphase cage rotor[edit]

text: Most common AC motors use the squirrel-cage rotor, which will be found in virtually all domestic and light industrial alternating current motors. The squirrel-cage refers to the rotating exercise cage for pet animals. The motor takes its name from the shape of its rotor "windings"- a ring at either end of the rotor, with bars connecting the rings running the length of the rotor. It is typically cast aluminum or copper poured between the iron laminates of the rotor, and usually only the end rings will be visible. The vast majority of the rotor currents will flow through the bars rather than the higher-resistance and usually varnished laminates. Very low voltages at very high currents are typical in the bars and end rings; high efficiency motors will often use cast copper to reduce the resistance in the rotor.

text: In operation, the squirrel-cage motor may be viewed as a transformer with a rotating secondary. When the rotor is not rotating in sync with the magnetic field, large rotor currents are induced; the large rotor currents magnetize the rotor and interact with the stator's magnetic fields to bring the rotor almost into synchronization with the stator's field. An unloaded squirrel-cage motor at rated no-load speed will consume electrical power only to maintain rotor speed against friction and resistance losses. As the mechanical load increases, so will the electrical load – the electrical load is inherently related to the mechanical load. This is similar to a transformer, where the primary's electrical load is related to the secondary's electrical load.

text: This is why a squirrel-cage blower motor may cause household lights to dim upon starting, but does not dim the lights on startup when its fan belt (and therefore mechanical load) is removed. Furthermore, a stalled squirrel-cage motor (overloaded or with a jammed shaft) will consume current limited only by circuit resistance as it attempts to start. Unless something else limits the current (or cuts it off completely) overheating and destruction of the winding insulation is the likely outcome.

text: Virtually every washing machine, dishwasher, standalone fan, record player, etc. uses some variant of a squirrel-cage motor.[citation needed]

text: Polyphase wound rotor[edit]

text: An alternate design, called the wound rotor, is used when variable speed is required. In this case, the rotor has the same number of poles as the stator and the windings are made of wire, connected to slip rings on the shaft. Carbon brushes connect the slip rings to a controller such as a variable resistor that allows changing the motor's slip rate. In certain high-power variable-speed wound rotor drives, the slip-frequency energy is captured, rectified, and returned to the power supply through an inverter. With bidirectionally controlled power, the wound rotor becomes an active participant in the energy conversion process, with the wound rotor doubly fed configuration showing twice the power density.

text: Compared to squirrel cage rotors, wound rotor motors are expensive and require maintenance of the slip rings and brushes, but they were the standard form for variable speed control before the advent of compact power electronic devices. Transistorized inverters with variable-frequency drive can now be used for speed control, and wound rotor motors are becoming less common.

text: Several methods of starting a polyphase motor are used. Where a large inrush current and high starting torque can be permitted, the motor can be started across the line, by applying full line voltage to the terminals (direct-on-line, DOL). Where it is necessary to limit the starting inrush current (where the motor is large compared with the short-circuit capacity of the supply), the motor is started at reduced voltage using either series inductors, an autotransformer, thyristors, or other devices. A technique sometimes used is star-delta (YΔ) starting, where the motor coils are initially connected in star configuration for acceleration of the load, then switched to delta configuration when the load is up to speed. This technique is more common in Europe than in North America. Transistorized drives can directly vary the applied voltage as required by the starting characteristics of the motor and load.

text: This type of motor is becoming more common in traction applications such as locomotives, where it is known as the asynchronous traction motor[citation needed].

text: Two-phase servo motor[edit]

text: A typical two-phase AC servo-motor has a squirrel cage rotor and a field consisting of two windings:

text:
a constant-voltage (AC) main winding.
a control-voltage (AC) winding in quadrature (i.e., 90 degrees phase shifted) with the main winding so as to produce a rotating magnetic field. Reversing phase makes the motor reverse.

tag: ol

text: An AC servo amplifier, a linear power amplifier, feeds the control winding. The electrical resistance of the rotor is made high intentionally so that the speed–torque curve is fairly linear. Two-phase servo motors are inherently high-speed, low-torque devices, heavily geared down to drive the load.

text: Single-phase induction motor[edit]

text: Single-phase motors do not have a unique rotating magnetic field like multi-phase motors. The field alternates (reverses polarity) between pole pairs and can be viewed as two fields rotating in opposite directions. They require a secondary magnetic field that causes the rotor to move in a specific direction. After starting, the alternating stator field is in relative rotation with the rotor. Several methods are commonly used:

text: Shaded-pole motor[edit]

text: A common single-phase motor is the shaded-pole motor and is used in devices requiring low starting torque, such as electric fans, small pumps, or small household appliances. In this motor, small single-turn copper "shading coils" create the moving magnetic field. Part of each pole is encircled by a copper coil or strap; the induced current in the strap opposes the change of flux through the coil. This causes a time lag in the flux passing through the shading coil, so that the maximum field intensity moves higher across the pole face on each cycle. This produces a low level rotating magnetic field which is large enough to turn both the rotor and its attached load. As the rotor picks up speed the torque builds up to its full level as the principal magnetic field is rotating relative to the rotating rotor.

text: A reversible shaded-pole motor was made by Barber-Colman several decades ago. It had a single field coil, and two principal poles, each split halfway to create two pairs of poles. Each of these four "half-poles" carried a coil, and the coils of diagonally opposite half-poles were connected to a pair of terminals. One terminal of each pair was common, so only three terminals were needed in all.

text: The motor would not start with the terminals open; connecting the common to one other made the motor run one way, and connecting common to the other made it run the other way. These motors were used in industrial and scientific devices.

text: An unusual, adjustable-speed, low-torque shaded-pole motor could be found in traffic-light and advertising-lighting controllers. The pole faces were parallel and relatively close to each other, with the disc centred between them, something like the disc in a watthour meter. Each pole face was split, and had a shading coil on one part; the shading coils were on the parts that faced each other. Both shading coils were probably closer to the main coil; they could have both been farther away, without affecting the operating principle, just the direction of rotation.

text: Applying AC to the coil created a field that progressed in the gap between the poles. The plane of the stator core was approximately tangential to an imaginary circle on the disc, so the travelling magnetic field dragged the disc and made it rotate.

text: The stator was mounted on a pivot so it could be positioned for the desired speed and then clamped in position. Keeping in mind that the effective speed of the travelling magnetic field in the gap was constant, placing the poles nearer to the centre of the disc made it run relatively faster, and toward the edge, slower.

text: It is possible that these motors are still in use in some older installations.

text: Split-phase motor[edit]

text: Another common single-phase AC motor is the split-phase induction motor,[18] commonly used in major appliances such as air conditioners and clothes dryers. Compared to the shaded pole motor, these motors provide much greater starting torque.

text: A split-phase motor has a secondary startup winding that is 90 electrical degrees to the main winding, always centered directly between the poles of the main winding, and connected to the main winding by a set of electrical contacts. The coils of this winding are wound with fewer turns of smaller wire than the main winding, so it has a lower inductance and higher resistance. The position of the winding creates a small phase shift between the flux of the main winding and the flux of the starting winding, causing the rotor to rotate. When the speed of the motor is sufficient to overcome the inertia of the load, the contacts are opened automatically by a centrifugal switch or electric relay. The direction of rotation is determined by the connection between the main winding and the start circuit. In applications where the motor requires a fixed rotation, one end of the start circuit is permanently connected to the main winding, with the contacts making the connection at the other end.

text: Capacitor start motor[edit]

text: A capacitor start motor is a split-phase induction motor with a starting capacitor inserted in series with the startup winding, creating an LC circuit which produces a greater phase shift (and so, a much greater starting torque) than both split-phase and shaded pole motors.

text: Resistance start motor[edit]

text: A resistance start motor is a split-phase induction motor with a starter inserted in series with the startup winding, creating reactance. This added starter provides assistance in the starting and initial direction of rotation.

text: Permanent-split capacitor motor[edit]

text: Another variation is the permanent-split capacitor (or PSC) motor.[19] Also known as a capacitor-run motor, this type of motor uses a non-polarized capacitor with a high voltage rating to generate an electrical phase shift between the run and start windings. PSC motors are the dominant type of split-phase motor in Europe and much of the world, but in North America, they are most frequently used in variable torque applications (like blowers, fans, and pumps) and other cases where variable speeds are desired.

text: A capacitor with a relatively low capacitance, and relatively high voltage rating, is connected in series with the start winding and remains in the circuit during the entire run cycle.[19] Like other split-phase motors, the main winding is used with a smaller start winding, and rotation is changed by reversing the connection between the main winding and the start circuit, or by having polarity of main winding switched while start winding is always connected to a capacitor. There are significant differences, however; the use of a speed sensitive centrifugal switch requires that other split-phase motors must operate at, or very close to, full speed. PSC motors may operate within a wide range of speeds, much lower than the motor's electrical speed. Also, for applications like automatic door openers that require the motor to reverse rotation often, the use of a mechanism requires that a motor must slow to a near stop before contact with the start winding is re-established. The 'permanent' connection to the capacitor in a PSC motor means that changing rotation is instantaneous.

text: Three-phase motors can be converted to PSC motors by making common two windings and connecting the third via a capacitor to act as a start winding. However, the power rating needs to be at least 50% larger than for a comparable single-phase motor due to an unused winding.[20]

text: Synchronous motor[edit]

text: Polyphase synchronous motor[edit]

text: If connections to the rotor coils of a three-phase motor are taken out on slip-rings and fed a separate field current to create a continuous magnetic field (or if the rotor consists of a permanent magnet), the result is called a synchronous motor because the rotor will rotate synchronously with the rotating magnetic field produced by the polyphase electrical supply. Another synchronous motor system is the brushless wound-rotor doubly fed synchronous motor system with an independently excited rotor multiphase AC winding set that may experience slip-induction beyond synchronous speeds but like all synchronous motors, does not rely on slip-induction for torque production.

text: The synchronous motor can also be used as an alternator.

text: Nowadays, synchronous motors are frequently driven by transistorized variable-frequency drives. This greatly eases the problem of starting the massive rotor of a large synchronous motor. They may also be started as induction motors using a squirrel-cage winding that shares the common rotor: once the motor reaches synchronous speed, no current is induced in the squirrel-cage winding so it has little effect on the synchronous operation of the motor, aside from stabilizing the motor speed on load changes.

text: Synchronous motors are occasionally used as traction motors; the TGV may be the best-known example of such use.

text: Huge numbers of three phase synchronous motors are now fitted to electric cars. They have a Nd or other rare-earth permanent magnet.

text: One use for this type of motor is its use in a power factor correction scheme. They are referred to as synchronous condensers. This exploits a feature of the machine where it consumes power at a leading power factor when its rotor is over excited. It thus appears to the supply to be a capacitor, and could thus be used to correct the lagging power factor that is usually presented to the electric supply by inductive loads. The excitation is adjusted until a near unity power factor is obtained (often automatically). Machines used for this purpose are easily identified as they have no shaft extensions. Synchronous motors are valued in any case because their power factor is much better than that of induction motors, making them preferred for very high power applications.

text: Some of the largest AC motors are pumped-storage hydroelectricity generators that are operated as synchronous motors to pump water to a reservoir at a higher elevation for later use to generate electricity using the same machinery. Six 500-megawatt generators are installed in the Bath County Pumped Storage Station in Virginia, USA. When pumping, each unit can produce 642,800 horsepower (479.3 megawatts).[21].

text: Single-phase synchronous motor[edit]

text: Small single-phase AC motors can also be designed with magnetized rotors (or several variations on that idea; see "Hysteresis synchronous motors" below).

text: If a conventional squirrel-cage rotor has flats ground on it to create salient poles and increase reluctance, it will start conventionally, but will run synchronously, although it can provide only a modest torque at synchronous speed. This is known as a reluctance motor.

text: Because inertia makes it difficult to instantly accelerate the rotor from stopped to synchronous speed, these motors normally require some sort of special feature to get started. Some include a squirrel-cage structure to bring the rotor close to synchronous speed. Various other designs use a small induction motor (which may share the same field coils and rotor as the synchronous motor) or a very light rotor with a one-way mechanism (to ensure that the rotor starts in the "forward" direction). In the latter instance, applying AC power creates chaotic (or seemingly chaotic) jumping movement back and forth; such a motor will always start, but lacking the anti-reversal mechanism, the direction it runs is unpredictable. The Hammond organ tone generator used a non-self-starting synchronous motor (until comparatively recently), and had an auxiliary conventional shaded-pole starting motor. A spring-loaded auxiliary manual starting switch connected power to this second motor for a few seconds.

text: Hysteresis synchronous motor[edit]

text: These motors are relatively costly, and are used where exact speed (assuming an exact-frequency AC source) as well as rotation with a very small amount of fast variations in speed (called "flutter" in audio recordings) is essential. Applications included tape recorder capstan drives (the motor shaft could be the capstan), and, before the advent of crystal control, motion picture cameras and recorders. Their distinguishing feature is their rotor, which is a smooth cylinder of a magnetic alloy that stays magnetized, but can be demagnetized fairly easily as well as re-magnetized with poles in a new location. Hysteresis refers to how the magnetic flux in the metal lags behind the external magnetizing force; for instance, to demagnetize such a material, one could apply a magnetizing field of opposite polarity to that which originally magnetized the material. These motors have a stator like those of capacitor-run squirrel-cage induction motors. On startup, when slip decreases sufficiently, the rotor becomes magnetized by the stator's field, and the poles stay in place. The motor then runs at synchronous speed as if the rotor were a permanent magnet. When stopped and restarted, the poles are likely to form at different locations. For a given design, torque at synchronous speed is only relatively modest, and the motor can run at below synchronous speed. In simple words, it is lagging magnetic field behind magnetic flux.

text: Other AC motor types[edit]

text: Universal motor and series wound motor[edit]

text: A universal motor is a design that can operate on either AC or DC power. In universal motors the stator and rotor of a brushed DC motor are both wound and supplied from an external source, with the torque being a function of the rotor current times the stator current so reversing the current in both rotor and stator does not reverse the rotation. Universal motors can run on AC as well as DC provided the frequency is not so high that the inductive reactance of the stator winding and eddy current losses become problems. Nearly all universal motors are series-wound because their stators have relatively few turns, minimizing inductance. Universal motors are compact, have high starting torque and can be varied in speed over a wide range with relatively simple controls such as rheostats and PWM choppers. Compared with induction motors, universal motors do have some drawbacks inherent to their brushes and commutators: relatively high levels of electrical and acoustic noise, low reliability and more frequent required maintenance.

text: Universal motors are widely used in small home appliances and hand power tools. Until the 1970s they dominated electric traction (electric, including diesel-electric railway and road vehicles); many traction power networks still use special low frequencies such as 16.7 and 25 Hz to overcome the aforementioned problems with losses and reactance. Still widely used, universal traction motors have been increasingly displaced by polyphase AC induction and permanent magnet motors with variable-frequency drives made possible by modern power semiconductor devices.

text: Repulsion motor[edit]

text: Repulsion motors are wound-rotor single-phase AC motors that are a type of induction motor. In a repulsion motor, the armature brushes are shorted together rather than connected in series with the field, as is done with universal motors. By transformer action, the stator induces currents in the rotor, which create torque by repulsion instead of attraction as in other motors. Several types of repulsion motors have been manufactured, but the repulsion-start induction-run (RS-IR) motor has been used most frequently. The RS-IR motor has a centrifugal switch that shorts all segments of the commutator so that the motor operates as an induction motor once it is close to full speed. Some of these motors also lift the brushes out of contact with source voltage regulation. Repulsion motors were developed before suitable motor starting capacitors were available, and few repulsion motors are sold as of 2005.

text: Exterior rotor[edit]

text: Where speed stability is important, some AC motors (such as some Papst motors) have the stator on the inside and the rotor on the outside to optimize inertia and cooling.

text: Sliding rotor motor[edit]

text: A conical rotor brake motor incorporates the brake as an integral part of the conical sliding rotor. When the motor is at rest, a spring acts on the sliding rotor and forces the brake ring against the brake cap in the motor, holding the rotor stationary. When the motor is energized, its magnetic field generates both an axial and a radial component. The axial component overcomes the spring force, releasing the brake; while the radial component causes the rotor to turn. There is no additional brake control required.

text: The high starting torque and low inertia of the conical rotor brake motor has proven to be ideal for the demands of high cycle dynamic drives in applications since the motor was invented, designed and introduced over 50 years ago. This type of motor configuration was first introduced in the USA in 1963.

text: Single-speed or two speed motors are designed for coupling to gear motor system gearboxes. Conical rotor brake motors are also used to power micro speed drives.

text: Motors of this type can also be found on overhead cranes and hoists. The micro speed unit combines two motors and an intermediate gear reducer. These are used for applications where extreme mechanical positioning accuracy and high cycling capability are needed. The micro speed unit combines a “main” conical rotor brake motor for rapid speed and a “micro” conical rotor brake motor for slow or positioning speed. The intermediate gearbox allows a range of ratios, and motors of different speeds can be combined to produce high ratios between high and low speed.

text: Electronically commutated motor[edit]

text: Electronically commutated (EC) motors are electric motors powered by direct-current (DC) electricity and having electronic commutation systems, rather than mechanical commutators and brushes. The current-to-torque and frequency-to-speed relationships of BLDC motors are linear. While the motor coils are powered by DC, power may be rectified from AC within the casing.

text: Watthour-meter motor[edit]

text: These are two-phase induction motors with permanent magnets to retard the rotor so its speed is accurately proportional to the power passing through the meter. The rotor is an aluminium-alloy disc, and currents induced into it react with the field from the stator.

text: A split-phase watthour meter has a stator with three coils facing the disc. The magnetic circuit is completed by a C-shaped core of permeable iron. The "voltage" coil above the disc is in parallel with the supply; its many turns have a high inductance/resistance ratio (Q) so its current and magnetic field are the time integral of the applied voltage, lagging it by 90 degrees. This magnetic field passes down perpendicularly through the disc, inducing circular eddy currents in the plane of the disc centered on the field. These induced currents are proportional to the time derivative of the magnetic field, leading it by 90 degrees. This puts the eddy currents in phase with the voltage applied to the voltage coil, just as the current induced in the secondary of a transformer with a resistive load is in phase with the voltage applied to its primary.

text: The eddy currents pass directly above the pole pieces of two "current" coils under the disc, each wound with a few turns of heavy-gauge wire whose inductive reactance is small compared to the load impedance. These coils connect the supply to the load, producing a magnetic field in phase with the load current. This field passes from the pole of one current coil up perpendicularly through the disc and back down through the disc to the pole of the other current coil, with a completed magnetic circuit back to the first current coil. As these fields cross the disc, they pass through the eddy currents induced in it by the voltage coil producing a Lorentz force on the disc mutually perpendicular to both. Assuming power is flowing to the load, the flux from the left current coil crosses the disc upwards where the eddy current flows radially toward the center of the disc producing (by the right-hand rule) a torque driving the front of the disc to the right. Similarly, the flux crosses down through the disc to the right current coil where the eddy current flows radially away from the disc center, again producing a torque driving the front of the disc to the right. When the AC polarity reverses, the eddy currents in the disc and the direction of the magnetic flux from the current coils both change, leaving the direction of the torque unchanged.

text: The torque is thus proportional to the instantaneous line voltage times the instantaneous load current, automatically correcting for power factor. The disc is braked by a permanent magnet so that speed is proportional to torque and the disc mechanically integrates real power. The mechanical dial on the meter reads disc rotations and the total net energy delivered to the load. (If the load supplies power to the grid, the disc rotates backwards unless prevented by a ratchet, thus making net metering possible.)

text: In a split-phase watthour meter the voltage coil is connected between the two "hot" (line) terminals (240V in North America[citation needed]) and two separate current coils are connected between the corresponding line and load terminals. No connection to the system neutral is needed to correctly handle combined line-to-neutral and line-to-line loads. Line-to-line loads draw the same current through both current coils and spin the meter twice as fast as a line-to-neutral load drawing the same current through only a single current coil, correctly registering the power drawn by the line-to-line load as twice that of the line-to-neutral load.

text: Other variations of the same design are used for polyphase (e.g., three-phase) power.

text: Slow-speed synchronous timing motor[edit]

text: Representative are low-torque synchronous motors with a multi-pole hollow cylindrical magnet (internal poles) surrounding the stator structure. An aluminum cup supports the magnet. The stator has one coil, coaxial with the shaft. At each end of the coil are a pair of circular plates with rectangular teeth on their edges, formed so they are parallel with the shaft. They are the stator poles. One of the pair of discs distributes the coil's flux directly, while the other receives flux that has passed through a common shading coil. The poles are rather narrow, and between the poles leading from one end of the coil are an identical set leading from the other end. In all, this creates a repeating sequence of four poles, unshaded alternating with shaded, that creates a circumferential traveling field to which the rotor's magnetic poles rapidly synchronize. Some stepping motors have a similar structure.


document_title: The Curse of Oak Island

question_text: who is financing the curse of oak island

root

text: The Curse of Oak Island

text: Overview[edit]

text: The Curse of Oak Island follows brothers Marty and Rick Lagina, originally from Kingsford, Michigan, through their efforts to find the speculated treasure or historical artifacts believed to be on Oak Island. The series discusses the history of the island, recent discoveries, theories, and prior attempts to investigate the site.[5] Areas of interest include the "Money Pit", Borehole 10-x, Smith's Cove, "Nolan's Cross", the "Hatch" and the "Swamp".

tag: p

text: Background[edit]

text: The Lagina brothers became fascinated with the island after reading the January 1965 issue of Reader's Digest magazine that features an article on the Restall family's work to investigate the so-called "Money Pit".[6] Marty and his brother Rick obtained a controlling interest in Oak Island Tours, which reportedly owns most of the island. The brothers were later approached by Prometheus Entertainment to do a reality show. Rick and Marty have engaged the assistance of father-and-son Dan and Dave Blankenship, permanent residents of the island who have likewise been searching for treasure since the 1960s.[7]

text: Theories[edit]

text: The series explores various Oak Island theories through conversations with independent researchers. Persons featured have included Zena Halpern discussing her theory about North African gold and sharing copies of a French map of the island which she claims is dated 1347; J. Hutton Pulitzer discussing his theory of ancient mariner visitations; Petter Amundsen discussing his theory about codes hidden in Shakespearen literature and a secret project involving Sir Francis Bacon and the Rosicrucians; Daniel Ronnstam discussing his theory about the 90 foot stone being a dual cypher containing instructions as how to defeat the money pit flood tunnels with corn; authors Kathleen McGowen and Alen Butler discussing their theory involving the fabled Knights Templar treasure and an alleged relocation of historical religious artifacts to the island; and John O'Brien discussing his theory that the island contains treasures of the Aztec Empire.

text: Series overview[edit]

text:
Season
Episodes
Originally aired

First aired
Last aired

1
5
January 5, 2014 (2014-01-05)
February 9, 2014 (2014-02-09)

2
10
November 4, 2014 (2014-11-04)
January 13, 2015 (2015-01-13)

3
13
November 10, 2015 (2015-11-10)
February 2, 2016 (2016-02-02)

4
16
November 15, 2016 (2016-11-15)[8]
February 21, 2017

5
TBA
November 7, 2017 (2017-11-07)[9]
TBA

tag: table

text: Production[edit]

text: Having started in 2014, The Curse of Oak Island is currently in its fifth season. On August 2, 2016, it was announced that Nova Scotia Business Inc. approved $1,271,546 in film funding for the production of the 4th season.[10] In October 2017, a fifth season was announced, which began airing on November 7, 2017.[11]

text: Episodes[edit]

text: Season 1 (2014)[edit]

text:
No.
overall
No. in
season
Title
Original air date
Viewers
(millions)

1
1
"What Lies Below"
January 5, 2014 (2014-01-05)
2.53[12]

Brothers Rick and Marty Lagina now own most of Oak Island. Determined to resume the search for treasure on the island, they explore an abandoned shaft called Borehole 10-X and use water pressure to pump material to the surface. They find a tiny piece of metal.

2
2
"The Mystery of Smith's Cove"
January 12, 2014 (2014-01-12)
2.35[13]

A scuba team that includes Marty's son Alex Lagina dives Smith's Cove and finds what are claimed to be non-indigenous coconut fibres and anomalous stones. Meanwhile, more metal fragments and cat bones are found in the slurry from 10-X.

3
3
"Voices from the Grave"
January 19, 2014 (2014-01-19)
2.33[14]

As Rick and Marty Lagina begin working to drain a swamp, they are visited by a woman who lost her father and brother to a tragic accident on Oak Island.

4
4
"The Secret of Solomon's Temple"
January 26, 2014 (2014-01-26)
2.72[15]

A visitor to the island presents Rick and Marty Lagina with his theory about where the treasure on Oak Island is located and the idea that the Menorah might be among the treasures for which they are searching.

5
5
"The Find"
February 9, 2014 (2014-02-09)
2.97[16]

The team digs in a shallow muddy swamp and finds what appears to be an antique Spanish copper coin. A diver is later sent into the swamp and finds no additional objects.

text: Season 2 (2014–2015)[edit]

text:
No.
overall
No. in
season
Title
Original air date
Viewers
(millions)

6
1
"Once In, Forever In"
November 4, 2014 (2014-11-04)
2.60[17]

After dating the Spanish coin they found last summer to 1652, brothers Rick and Marty Lagina return to Oak Island and begin searching the swamp again.

7
2
"Return To The Money Pit"
November 11, 2014 (2014-11-11)
2.15[18]

The team drills in the area of the money pit but is unable to drill through the underground material. A visitor shows them alleged evidence that the treasures from King Solomon's Temple could be buried on Oak Island.

8
3
"The Eight-Pointed Star"
November 18, 2014 (2014-11-18)
2.23[19]

A treasure hunter presents a theory that Phoenicians visited the island 2500 years ago and left behind the ark of the covenant. Rick and Marty Lagina unsuccessfully look for evidence to prove it while also trying to locate the original Money Pit.

9
4
"The Breakthrough"
November 25, 2014 (2014-11-25)
2.15[20]

A tree stump in the swamp is examined. Core samples extracted by drilling are discovered to contain rocks and wood.

10
5
"The 90-Foot Stone"
December 2, 2014 (2014-12-02)
2.46[21]

A visitor comes to the island suggesting that he has discovered a secret method of getting to the treasure. He claims that Francis Bacon has left behind instructions to the effect that the "flood tunnels" can be disabled by pouring corn into the money pit. The team declines to test the theory and instead visits a masonic lodge. The team searches the swamp again and finds nothing.

11
6
"Seven Must Dye"
December 9, 2014 (2014-12-09)
2.90[22]

Rick searches for man-made flood tunnels without success; Marty and John visit Europe to track down a lead.

12
7
"The Trail of the Templars"
December 16, 2014 (2014-12-16)
2.47[23]

While work begins in the swamp, Rick and Marty travel to Scotland to investigate more corn-related theories about the money pit. They are also presented with a theory that Oak Island is a copy of King Solomon's Temple and that the entrance to the Money Pit is in the swamp.

13
8
"X Marks the Spot"
December 23, 2014 (2014-12-23)
2.72[24]

Rick and Marty search the swamp for an alternate entrance into the Money Pit, without success.

14
9
"A Dangerous Dive"
January 6, 2015 (2015-01-06)
2.59[25]

Rick and Marty take a team of divers to Oak Island.

15
10
"The Big Reveal"
January 13, 2015 (2015-01-13)
3.06[26]

Rick and Marty use sonar to map out the bottom chamber of the 10-X borehole.

text: Season 3 (2015–2016)[edit]

text:
No.
overall
No. in
season
Title
Original air date
Viewers
(millions)

16
1
"The Hole Truth"
November 10, 2015 (2015-11-10)
2.26[28]

Rick and Marty search for underground tunnels on Oak Island and prep borehole 10-X for a dive.[27]

17
2
"Pipe Down"
November 17, 2015 (2015-11-17)
2.56[30]

Prep work for a dive in borehole 10X continues while the team simultaneously searches the area near the Money Pit for shallow treasure.[29]

18
3
"Time to Dig"
November 24, 2015 (2015-11-24)
2.60[32]

Rick, Marty and the team go shopping for excavation equipment, investigate the location of a possible Knight's Templar treasure and search for the original location of the Money Pit.[31]

19
4
"The Overton Stone"
December 1, 2015 (2015-12-01)
3.05[34]

Work continues to locate the Money Pit while the team investigates a stone with purported Portuguese carvings.[33]

20
5
"Disappearing Act"
December 8, 2015 (2015-12-08)
3.22[36]

The team completes preparations for a dive expedition down borehole 10X by investigating the shaft with a camera.[35]

21
6
"Carved in Stone"
December 15, 2015 (2015-12-15)[38]
2.47[39]

Rick, Marty and the team investigate rocks on Oak Island. A researcher visits the island and claims that the Aztecs may have visited the island in the past.[37]

22
7
"The Missing Peace"
December 22, 2015 (2015-12-22)[38]
3.40[41]

Rick and Marty welcome long-time rival Fred Nolan into the team.[40]

23
8
"Phantoms of the Deep"
December 29, 2015 (2015-12-29)[38]
3.30[43]

The team conducts a sonar sweep of the waters surrounding Oak Island and begin digging on Fred Nolan's property.[42]

24
9
"Columbus Day"
January 5, 2016 (2016-01-05)[38]
2.79[45]

The team preps for a dive of borehole 10X. They also listen to a theory about Christopher Columbus visiting the Island.[44]

25
10
"Silence in the Dark"
January 12, 2016 (2016-01-12)[38]
3.11[47]

Difficulties are encountered during the dive to the bottom of borehole 10X, the team further investigates Fred Nolan's property and an alleged Roman sword found in the waters off Oak Island is presented to the team.[46]

26
11
"Sword Play"
January 19, 2016 (2016-01-19)[38]
2.82[49]

The team has the Roman sword investigated and find that it is a modern reproduction. There is an unproductive search for treasure north of the Money Pit.[48]

27
12
"Voices from Below"
January 26, 2016 (2016-01-26)[38]
3.17[51]

The team dives to the bottom of borehole 10X. In a separate investigation, a cavity is found far underground near the Money Pit.[50]

28
13
"Secrets and Revelations"
February 2, 2016 (2016-02-02)[38]
3.41[52]

The diving investigation of borehole 10X concludes with nothing found. Relatives of the original Oak Island treasure hunters present a gold cross which is said to have come from the treasure.

text: Season 4 (2016–2017)[edit]

text:
No.
overall
No. in
season
Title
Original air date
Viewers
(millions)

29
1
"Going for Broke"
November 15, 2016 (2016-11-15)
2.62[54]

The team agrees to turn focus over to the Money Pit and review what they have collected. A researcher presents a copy of what she claims is a French map from 1347 of Oak Island. The map shows locations for a "hatch", a "valve" and an "anchor" on the Island. A theory is presented based on a purported decoding of a cipher that Joab at the time of King David transported the Ark of the Covenant to North Africa from which it was later transported onward by the Knights Templar from the then-Portuguese town of Safi in Morocco to Oak Island.[53]

30
2
"Always Forward"
November 22, 2016 (2016-11-22)
2.66[55]

While preparing to excavate the Money Pit, the team investigates an 18th century well on mainland Nova Scotia. The team brings in an archaeologist to inspect a hole on Dave Blankenship's property which they think is a potential "hatch".

31
3
"Swamp Things"
November 29, 2016 (2016-11-29)
2.97[56]

A piece of rock with scratches is found, before the team revisits the swamp for another look and finds very little.

32
4
"No Stone Unturned"
December 6, 2016 (2016-12-06)
2.95[57]

Part of the team unsuccessfully attempts to track down the '90-foot stone' in nearby Halifax; while the first excavation in over 50 years begins in the Money Pit.

33
5
"Bullseye"
December 11, 2016 (2016-12-11)
2.82[58]

A new theory that Inca gold is buried on Oak Island is offered, albeit without evidence to support it. Meanwhile the team supposedly inches their way to the alleged target in the Money Pit.

34
6
"Circles in Wood"
December 20, 2016 (2016-12-20)
3.44[59]

A few coins are found on the island, a long way from the money pit. The money pit search for the 'Chappel Vault' ends in failure so a new target is set for 170ft C-1 shaft in the Money Pit area.

35
7
"All That Glitters"
December 27, 2016 (2016-12-27)
3.68[60]

The swamp is drained and searched with a metal detector revealing an old spike. Object not dated. C-1 Dig Site is drilled to target depth of 170 ft. where previously inserted camera may have seen something shiny and gold colored.

36
8
"The Mystery of Samuel Ball"
January 3, 2017 (2017-01-03)
3.43[61]

A tiny amount of evidence is offered supposedly linking an 18th-century slave to the mystery.

37
9
"Echoes from the Deep"
January 10, 2017 (2017-01-10)
3.35[62]

A camera sent down 10X confirms the divers impression that there is nothing there of note, undermining the camera's operators previous assertion that they were 90% certain there was a chest there. Some of the team are in denial about this and insist there is still some point in exploring 10-X further on the basis that Dan Blankenship has spent so much time on it, it must be the key to the alleged puzzle.

38
10
"About Face"
January 17, 2017 (2017-01-17)
3.04[63]

Divers are sent to the bottom of borehole C-1. Nothing is found. A rock fifty miles from Oak Island is examined. The team decides to do a new examination of borehole 10X.

39
11
"Presidential Secrets"
January 24, 2017 (2017-01-24)
3.20[64]

The new examination of borehole 10X concludes. Equipment failure delays excavation of a new hole. Rick heads to the Franklin D. Roosevelt library to learn why the late President was interested in Oak Island.

40
12
"Hyde Park & Seek"
January 31, 2017 (2017-01-31)
3.15[65]

A cofferdam is built at Smith's Cove and the beach is excavated. The team debates where the "money pit" might have been.

41
13
"One Of Seven"
February 7, 2017 (2017-02-07)
3.24[66]

The team attempts to decode a cipher and concludes that they only possess 1/7th of the cipher. Rocks are found at Smith's Cove. The investigation of the cove is halted for the year. A man from Arizona claims, without any evidence, that several hundred tons of gold are hidden in tunnels near Oak Island.

42
14
"Sticks and Stones"
February 14, 2017 (2017-02-14)
3.20[67]

Rocks are examined on Oak Island. Pieces of wood are carbon dated. The third excavation on the island this season reaches bedrock with nothing found. The team decides to dig another hole.

43
15
"Blood is Thicker"
February 21, 2017 (2017-02-21)
3.79[68]

The final excavation of the season leads to the discovery of scrap metal pieces, a washer, several hex nuts and a button. Season finale featured McGinnis gold cross, iron spike, and other artifacts evaluated by antiques appraiser Dr. Lori Verderame (Ph.D. - History of Art and Architecture).

Note: This episode aired as a 2-hour special.

44
16
"Drilling Down"
February 28, 2017 (2017-02-28)
1.72[69]

The team is interviewed at the end of season. The wood from borehole 10-X is carbon dated as being from 1670-1780. A new cipher is decoded leading the team to once again believe that there is a "hatch" somewhere on the island. The team wants to continue searching the swamp. The team proposes pumping borehole 10-X dry to enable yet another round of searches. The team wants to search more of the Island with metal detectors in the future.

Note: This episode is a special.

text: Season 5 (2017–2018)[edit]

text:
No.
overall
No. in
season
Title
Original air date
Viewers
(millions)

45
1
"Forever Family"
November 7, 2017 (2017-11-07)
2.95[70]

A diver is sent to the bottom of borehole C-1. Mud is recovered. A nail is found in an old spoils pile from GAL-1. A copper coin is found in the woods near Issac's Point.

46
2
"Dead Man's Chest"
November 14, 2017 (2017-11-14)
2.98[71]

The sea chest of a captain who lived in Nova Scotia in the 1780s is examined. Salt water starts coming out the top of borehole C-1. Another copper coin is found on the island.

47
3
"Obstruction"
November 21, 2017 (2017-11-21)
2.85[72]

Two old British copper coins are found in the woods. The Province of Nova Scotia requests that an archaeologist be on site on Oak Island as an adviser to the treasure hunters. Part of a metal spoon and round rocks are discovered under tree stumps. Based on the rocks and the spoon pieces, Marty Lagina concludes that "something must have happened here". A small piece of scrap metal is found in the mud brought up from one of the new boreholes being drilled in the "money pit" area.

48
4
"Close Call"
November 28, 2017 (2017-11-28)
3.36[73]

Drilling below bedrock, the team discovers a void in the rock. A hose on the drill detaches resulting in a worker falling backward and suffering a minor injury to his wrist. Drilling is halted for over a week. A toy gun is found in the woods and the team launches an investigation of it. Lee Lamb and Richard Restall visit the island. Richard Restall is identified conclusively as the owner of the toy gun.

49
5
"Bone Dry"
December 5, 2017 (2017-12-05)
3.16[74]

An iron spike is found on the beach. Some small pottery fragments are brought up from one of the boreholes. Two human bone fragments were recovered and sent in for testing.

50
6
"Remains of the Day"
December 12, 2017 (2017-12-12)
3.01[75]

A piece of leather is found. Rick Lagina has headaches and a rash. He is later diagnosed as having lyme disease. The team intends to have the previously discovered human bone fragments carbon dated.

51
7
"The Lot Thickens"
December 19, 2017 (2017-12-19)
TBD


document_title: Minor League Baseball

question_text: how many divisions are there in minor league baseball

question_tokens: how many divisions are there in minor league baseball

text: Minor League Baseball

text: History[edit]

text: The earliest professional baseball association, the National Association of 1871 to 1875, comprised all fully professional teams. This system proved unworkable, however, as there was no way to ensure competitive balance, and financially unsound clubs often failed in midseason. This problem was solved in 1876 with the formation of the National League, with a limited membership which excluded less competitive and financially weaker teams. Professional clubs outside the National League responded by forming regional associations of their own. There was a series of ad hoc groupings, such as the New England Association of 1877 and the Eastern Championship Association of 1881. These were loose groups of independent clubs which agreed to play a series of games for a championship pennant.

text: The first minor league is traditionally considered to be the Northwestern League of 1883 to 1884. Unlike the earlier minor associations, it was conceived as a permanent organization. It also, along with the National League and the American Association, was a party to the National Agreement of 1883. Included in this was the agreement to respect the reserve lists of clubs in each league. Teams in the National League and the American Association could only reserve players who had been paid at least $1000. Northwest League teams could reserve players paid merely $750, implicitly establishing the division into major and minor leagues. Over the next two decades, more minor leagues signed various versions of the National Agreement. Eventually, the minor leagues joined together to negotiate jointly.

text: In the late 1890s, the Western League run by the fiery Ban Johnson decided to challenge the National League's position. In 1900, he changed the name of the league to the American League and vowed to make deals to sign contracts with players who were dissatisfied with the pay and terms of their deals with the National League. This led to a nasty turf war that heated up in 1901 enough to concern Patrick T. Powers, president of the Eastern League, and many other minor league owners about the conflict potentially affecting their organizations. Representatives of the different minor leagues met at the Leland Hotel in Chicago on September 5, 1901. In response to the National–American battle, they agreed to form the National Association of Professional Baseball Leagues, called the NAPBL, or NA for short. (The NA uses the name Minor League Baseball today.) The purpose of the NA at the time was to maintain the independence of the leagues involved. Several did not sign the agreement and continued to work independently. Powers was made the first president of the NAPBL, whose offices were established in Auburn, New York.

text: In 1903, the conflict between the American and National Leagues ended in the National Agreement of 1903.[2] The NAPBL became involved in the later stages of the negotiations to develop rules for the acquisition of players from their leagues by the National and the American. The 1903 agreement ensured that teams would be compensated for the players that they had taken the time and effort to scout and develop, and no NA team was required to sell their players, although most did because the cash was an important source of revenue for most teams. The NA leagues were still fiercely independent, and the term "minor" was seldom used in reference to them, save by the major-market sports writers. News did not travel far in the days before television and radio, so, while the leagues often bristled at the major market writers descriptions, they viewed themselves as independent sports businesses. Many baseball writers of that time regarded the greatest players of the minor leagues, such as Buzz Arlett, Jigger Statz, Ike Boone, Buddy Ryan, Earl Rapp and Frank Shellenback, as comparable to major league players. Leagues in the NA would not be truly called minor until Branch Rickey developed the first modern farm system in the 1930s. The Commissioner of Baseball, Kenesaw Mountain Landis fought Rickey's scheme, but, ultimately, the Great Depression drove teams to establish systems like Rickey's to ensure a steady supply of players, as many NA and independent teams could not afford to keep their doors open without the patronage of major league baseball. The leagues of the NA became subordinate to the major leagues, creating the first minor leagues. Other than the Pacific Coast League, which under its president Pants Rowland tried to become a third major league in the Western states, the other leagues maintained autonomy in name only, being totally economically dependent upon the American and National leagues.

text: In 1922, the United States Supreme Court decision Federal Baseball Club v. National League (259 U.S. 200), which grants baseball a special immunity from antitrust laws, had a major effect on the minor leagues. The special immunity meant that the American and National leagues could dictate terms under which every independent league did business. By 1925, major league baseball established a flat-fee purchase amount of $5,000 for the contract of any player from an NA league team. This power was leveled primarily at the Baltimore Orioles, then a Triple-A team that had dominated the minors with stars.

text: Current system[edit]

text: Under most circumstances, minor league teams are not owned by major league clubs, but have affiliation contracts with them. A small number of minor league clubs are directly owned by major league clubs, but these are rare. Major league Rule 56 governs the standard terms of a Player Development Contract (PDC) which is the standard agreement of association between a minor league team and its major league affiliate. Generally, the parent major league club pays the salaries and benefits of uniformed personnel (players and coaches) and bats and balls, while the minor league club pays for in-season travel and other operational expenses.[3]

text: Minor league teams often change their affiliation with major league clubs for a variety of reasons. Sometimes major or minor League clubs wish to affiliate with a partner that is geographically closer. In recent years, some MLB clubs have attempted to place as many affiliated teams within their blackout area as possible, in order to make scouting and player transfers more convenient and to take advantage of the existing fan base when interest in the parent team builds support for the minor league affiliate and early fan interest in developing minor league players reinforces support for the parent team as "local players" reach the majors. Sometimes a minor league club wishes to improve the caliber of players its major league affiliate sends to play there. Sometimes a major league club wishes to improve the facility where it will send its developing players. In even-numbered years, any major or minor league club with an expiring PDC may notify Major League Baseball or Minor League Baseball, respectively, of its desire to explore a re-affiliation with a different PDC partner. The Major League Baseball and Minor League Baseball offices then send a list of the corresponding major and minor league clubs seeking new affiliations, and there is a limited period of time in September within which clubs may agree upon new PDCs. If any are left over after this process, the Major League Baseball and Minor League Baseball offices are empowered to assign major and minor league clubs to each other.

text: Going into the 2010 season, the longest continuous link between major league and minor league clubs was the link between the Orioles and their Rookie-level Appalachian League affiliate, the Bluefield Orioles. The teams were affiliated for 53 years, from 1958 through 2010. Baltimore ended the PDC after the 2010 season. At the start of the 2011 season, the longest continuous affiliations were two 45-year links: between the Philadelphia Phillies and their Double-A Eastern League affiliate, the Reading Fightin Phils; and the one between the Detroit Tigers and their Class A-Advanced Florida State League affiliate, the Lakeland Flying Tigers. Both Reading and Lakeland are owned by their parent Major League clubs.

text: There are several baseball clubs that operate teams at multiple levels of the minor leagues; they are not required to affiliate all of their clubs to the same major league franchise. Bob Rich, Jr., for example, owns the Triple-A Buffalo Bisons and the short-season West Virginia Black Bears, the latter of which had been the Jamestown Jammers before the 2015 season. Even though the teams were located slightly more than 70 miles (110 km) apart before the Jammers' relocation, Rich has never affiliated the two teams with the same parent club.

text: The current minor league classification system divides leagues into one of five classes, those being Triple-A (AAA), Double-A (AA), Class A (Single-A or A), Class A Short Season, and Rookie. Furthermore, Class A is further subdivided into Class A and Class A-Advanced (often called Low-A and High-A, respectively), and Rookie is further subdivided into Rookie Advanced, Complex-based Rookie and international summer baseball. Under the rules governing the affiliated minor leagues (specifically Major League Baseball Rule 51), Class A Short Season is a separate classification from the other leagues bearing the "Class A" name, despite the similarity in name.

text: Triple-A[edit]

text: This classification currently includes two affiliated leagues: the International League and the Pacific Coast League, which feature teams from Eastern and Western United States respectively.[4] For most of the 20th century, it also contained the American Association, based in the Midwest, but that league disbanded, its clubs absorbed by the other two leagues, as part of a reorganization of the Triple-A level in 1997. The Mexican League is also classified as a Triple-A league, though its clubs do not have PDCs with Major League clubs.

text: Both young players and veterans play for Triple-A teams. Teams usually hold many of the remaining 15 players of the 40-man major league roster whom the major league club has chosen not to play at the major league level. Players at Triple-A on the 40-man roster can be invited to come up to the major league club once the major league roster expands on September 1, although teams usually wait until their affiliates' playoff runs are over, should they qualify. For teams in contention for a pennant, it gives them fresh players. For those not in contention, it gives them an opportunity to evaluate their second-tier players against major-league competition.[5] Some Triple-A players are "career minor leaguers", former prospects whose skill growth has halted and are not likely to be ready for MLB action unless as a temporary replacement.[6]

text: Unlike at other levels of competition, the two affiliated Triple-A leagues meet each summer in the Triple-A All-Star Game, first played in 1988. Each league fields a team composed of the top players in their respective leagues as voted on by fans, the media, and each club's field manager and general manager.[7] In another instance of interleague play, the annual Triple-A Baseball National Championship Game has been held since 2006 to serve as a single championship game between the champions of the International League and Pacific Coast League to determine an overall champion of Triple-A baseball.[8]

text: Double-A[edit]

text: There are currently three leagues in this classification: Eastern League, Southern League, and the Texas League.[4] Some players jump to the majors from this level, as many of the top prospects are put here to play against each other rather than against minor and major league veterans in Triple-A.[6] A small handful of players might be placed here to start, usually veterans from foreign leagues with more experience in professional baseball. The expectation is usually that these players will be in the majors by the end of the season, as their salaries tend to be higher than those of most prospects.

text: Unlike the major league and the Triple-A level, two of the three Double-A leagues play a split season, the Eastern League being the exception. One team may clinch a spot in the playoffs by winning the division in first half of the season. The teams' records are then cleared and another team will also clinch a playoff slot during the second half. Wild cards are used to fill out the remaining teams. Usually, four teams qualify for the league playoffs. This system is used at the Class A level as well.

text: Class A-Advanced[edit]

text: One level below Double-A, the California League, Carolina League, and the Florida State League play at the Class A-Advanced level, also known as "Class A+" or "High A".[4] This is often a second or third promotion for a minor league player, although a few high first-round draftees, particularly those with college experience, begin at this level. These leagues play a complete season like Triple-A and Double-A, from April through early September. Many of the teams in the Florida State League are owned by major league parent clubs and use their spring training complexes. The class consists of 30 teams from around the United States, from San Jose to Tampa.

text: Class A[edit]

text: Slightly below Class A-Advanced are the full season Class A leagues, the South Atlantic League and Midwest League.[4] These leagues are a mix of players moving up from the Short Season and Rookie leagues, as well as the occasional experienced first-year player. These leagues play a full, 140 game schedule, which runs from the first week of April through the first week of September.

text: Short season leagues[edit]

text: Short season leagues, as the name implies, play a shortened season of 76 games, starting in mid-June and ending in early September, with only a few off-days during the season. The late start of the season is designed to allow college players to complete their college seasons in the spring, then be drafted, signed, and immediately placed in a competitive league (The MLB First Year Player Draft begins on the first Monday in June).

text: Players in short season leagues are a mixture of newly signed draftees who are considered more advanced than other draftees, and second-year pros who were not ready or for whom there was not space at a higher level to move up. Second-year pros are assigned to "extended spring training" in Florida or Arizona during April and May before reporting to their short season leagues.

text: Of the 30 major league clubs, 13 field teams in Class A Short Season only, 8 clubs field their top short season teams in the Rookie Advanced leagues, and 9 clubs have affiliates at both levels.

text: Class A Short Season[edit]

text: Class A Short Season, despite the name, is a separate classification from Class A. Class A Short Season teams are slightly more limited than Class A teams with respect to player age and years of experience in professional baseball. There are two short season leagues, the New York–Penn League and Northwest League.

text: Rookie Advanced[edit]

text: The Appalachian League and Pioneer League are known as "Rookie Advanced" leagues. The players in these leagues are thought to be further along in their development than players in the pure Rookie leagues, and hence games are more competitive. Teams in these leagues sell concessions and charge admission.

text: Rookie[edit]

text: Leagues in the Rookie classification play a shortened season, similar to, but slightly shorter than, the short season leagues, starting in mid-June and ending in late August or early September. This lowest level of minor league baseball consists of two domestic leagues, the Arizona League and Gulf Coast League, and one foreign-based league, the Dominican Summer League.[4]

text: The domestic Rookie leagues play a 60-game schedule, and are usually called "complex leagues" because games are played at their parent clubs' spring training complexes. Rosters comprise newly drafted players who are not ready for a higher level of play. These leagues are intended almost exclusively to allow players to hone their skills; no admission is charged and no concessions are sold.

text: Rehabilitation assignments[edit]

text: Players on the disabled list (DL) can be sent to the minor leagues to aid in rehabilitation following an injury, typically for one or two weeks. Players are often sent to minor league clubs based on geography and facilities, not necessarily by class for these reassignments.

text: Curt Schilling's recovery from an ankle injury in 2005 saw him rehab in Pawtucket, Rhode Island at the Triple-A Pawtucket Red Sox, very close to the home club in Boston. The Cincinnati Reds often send players to their Class A affiliate, the Dayton Dragons, for rehab assignments. Despite Dayton's status as Low Class A, Dayton is a short, 50-mile drive away from the Reds' Great American Ball Park.

text: Minnesota Twins superstar Joe Mauer, who missed most of the first two months of the 2011 season due to a difficult recovery from arthroscopic knee surgery after the 2010 season, reported to Minnesota's Class A-Advanced Florida State League team, the Fort Myers Miracle, which is based in their well-equipped Spring Training facility in Fort Myers. In addition, the Miracle manager at the time was Mauer's older brother Jake. The Twins would later send Joe Mauer and pitcher Ricky Nolasco to rehab with the club's Low-A affiliate located across the Minnesota-Iowa border in Cedar Rapids.[9]

text: Mike Trout's first rehab assignment of his career, in July 2017, was with the Inland Empire 66ers of San Bernardino, California, the Class A-Advanced affiliate of the Los Angeles Angels. This allowed Trout to stay closer to the Angels compared to the team's Triple-A affiliate, the Salt Lake Bees.[10]

text: Reorganization of 1963[edit]

text: The current minor league structure is largely based on a significant reorganization that occurred before the 1963 season, which was caused by the club and league contraction of the 1950s and early 1960s. In 1949, the peak of the post-World War II minor league baseball boom, 438 teams in 59 leagues were members of the National Association of Professional Baseball Leagues. By the end of 1963, only 15 leagues survived in the United States and Canada.[11]

text: Previous structure (1946–1962)[edit]

text: Before 1946, the minors' highest level was labeled Double-A. In 1946, the Triple-A classification was created and the three Double-A circuits (the Pacific Coast and International leagues, and the American Association) were automatically reclassified Triple-A. The Class A1 level, two rungs below the Majors and comprising the Texas League and the Southern Association, was then renamed Double-A.

text: Prior to 1963, the Class A level was a higher-rung classification. In 1946, Class A consisted of the Eastern League and the original South Atlantic or "Sally" League, and it would soon include the Western League (1947–1958), the Central League (1948–1951), and the Western International League (1952–1954). The WIL became the Class B Northwest League in 1955, and the Western and Central loops folded. But postwar Class A cities included communities such as Denver, in Major League Baseball since 1993, as well as Vancouver, Omaha, Colorado Springs, Scranton and Allentown, which would establish themselves as Triple-A venues.

text: The lower levels of the minors were ranked Classes B through D in descending order. With the exception of the 1952–1957 Open Classification experiment for the Pacific Coast League, this structure would remain intact through 1962. (see Defunct levels, below)

text: The 1963 classification realignment[edit]

text: After the 1962 season, the Triple-A American Association disbanded and the surviving International and Pacific Coast leagues absorbed the four remaining American Association franchises. Meanwhile, at the Double-A level and below there were even more significant changes:

text:
The two existing Class A leagues—the Eastern and South Atlantic—were upgraded to Double-A, joining the Texas League and the Mexican League, then Double-A, as members of this classification. This move was caused by the disbanding of the Southern Association after 1961, leaving the six-team Texas League as the only U.S.-based Double-A circuit in 1962. (The Mexican League, although a formal member of minor league baseball, was not affiliated with any Major League teams.) In addition, many Major League parent teams had frequently treated the pre-1963 Eastern and South Atlantic leagues as de facto Double-A circuits, one step (rather than two) below Triple-A.
The Class B Carolina League and Northwest League, the Class C California League, Pioneer League and Northern League, and the Class D Florida State League, Georgia–Florida League, Midwest League, New York–Penn League, and Western Carolinas League were all designated Class A (or Single-A) leagues. (The unaffiliated Mexican Central League of 1960–1978, ranked Class C in 1962, also was upgraded to Class A.)
The Class D Appalachian League, then the only "short-season" circuit, was given a new designation as a "Rookie" league.

tag: ul

text: As part of the 1963 reorganization, Major League clubs increased their commitments to affiliate with minor league teams through Player Development Contracts, outright ownerships, or shared affiliations and co-op arrangements.[11]

text: Further changes after 1963[edit]

text:
Triple-A: The American Association was revived as a Triple-A league in 1969 and flourished with the minor league baseball boom of the 1980s and 1990s. However, all of its teams were again absorbed into the International and Pacific Coast leagues in 1998 as part of a sweeping reorganization of the minors' top classification. The American Association and the International League also played an interlocking schedule during the late 1980s as part of the Triple-A Alliance. The Mexican League was upgraded from Double-A to Triple-A in 1967.
Double-A: In 1964, the South Atlantic League changed its name to its current identity, the Southern League. Because of continued contraction (and Major League expansion) that left each circuit with only seven teams, the Texas and Southern leagues merged into an umbrella circuit, the Dixie Association, in 1971. The arrangement lasted only for that season and the records and history of the Texas and Southern loops were kept distinct. In 1972, each league added an eighth team, rebalancing their schedules. They resumed their former, separate identities, and returned to prosperity with the revival of minor league baseball that began in the 1980s.
Class A: In 1965, the Class A–Short Season designation was created, and the Northern and Northwest loops moved from "full season" Class A into the new classification (with the New York–Penn League following in 1967). The Georgia–Florida League disbanded after the 1963 season, while the Northern League played its last year in official minor league baseball in 1971. In 1980, the Western Carolinas League changed its identity to become the modern incarnation of the South Atlantic League.
Rookie: In 1964, the Pioneer League stepped down from Class A to Rookie league status, and the first "complex-based" leagues, the Sarasota Rookie League and the Cocoa Rookie League, made their debuts. The Sarasota Rookie League underwent a name change to the Florida Rookie League in 1965 before becoming the modern Gulf Coast League the next season. The Cocoa Rookie League lasted only one season, and the Florida East Coast League of 1972, based in the same region of the state, also existed for only one year. In 1989, an Arizona-based counterpart to the Gulf Coast League, the Arizona League, made its debut in minor league baseball, and it continues to operate as a Rookie-level league for MLB teams with spring training facilities based in that state.
Failed start-up leagues: During the 1970s, three "official" minor leagues attempted unsuccessfully to revive unaffiliated baseball within the organized baseball structure. These were the Class A Gulf States League (1976) and Lone Star League (1977), and the Triple-A Inter–American League (1979). None lasted more than a full season.

text: Defunct levels[edit]

text: Open[edit]

text: The Pacific Coast League, from 1952–1957, was the only minor league to obtain open classification. At this time, the major leagues only extended as far west as St. Louis and as far south as Washington, D.C. This classification severely restricted the rights of the major leagues to draft players out of the PCL, and at the time it seemed like the PCL would eventually become a third major league. The PCL would revert to Triple-A classification in 1958 due to increasing television coverage of major league games and in light of the Dodgers and Giants moving to Los Angeles and San Francisco, respectively. The open classification no longer exists in the major league rules.

text: Class A1[edit]

text: The forerunner to the modern Double-A classification, the A1 level existed from 1936 through 1945. In 1936, two Class A circuits, the Texas League and the Southern Association, were upgraded to Class A1 to signify their continued status as one step below the highest classification, then Double-A, yet a notch above their former Class A peers, the New York–Pennsylvania League and Western League. Ten years later, after World War II, with the minor leagues poised for unprecedented growth, classification terminology was changed. Beginning in 1946, the three Double-A leagues (the American Association and International and Pacific Coast leagues) joined a new classification, Triple-A, and the Class A1 level became known as Double-A.

text: Class B, C and D[edit]

text: Until 1963, there were also Class B, C, and D leagues (and, for half a season, one E league). The Class D of that period would be equivalent to the Rookie level today. The other class designations disappeared because leagues of that level could not sustain operation during a large downturn in the financial fortunes of minor league baseball in the 1950s and 1960s caused by the rise of television broadcasts of major league sports across broad regions of the country. The impact of the Korean War in 1950 caused a player shortage in most cities in class D and C. The Class E level existed briefly in 1943 in the form of the Twin Ports League. It folded July 13 after six weeks of operation.

text: Players[edit]

text: Only 25 of the players on a Major League Baseball team's 40-man major league reserve list may be active for the major league club, with two exceptions. One minor exception is that when a team is scheduled to play a day-night doubleheader, it is allowed to carry 26 players on the active roster for that day only. The more significant exception is that from September 1 to the end of the regular season, teams are allowed to expand their game-day rosters to 40 players. The remaining 15 players are generally either on the disabled list or play at some level of the minor leagues (usually at the Triple-A or Double-A level). Players on the 40-man reserve list are eligible for membership in the Major League Baseball Players Association. The minor league players work at the lower end of major league pay scales and are covered by all rules and player agreements of the players association. Minor league players not on the 40-man reserve list are under contract to their respective parent Major League Baseball clubs but have no union. They generally work for far less pay as they develop their skills and work their way up the ladder toward the major leagues.[12] Many players have signing bonuses and other additional compensation that can run into the millions of dollars, although that is generally reserved for early round draft picks.

text: A major league team's Director of Player Development determines where a given player will be placed in the farm system, in coordination with the coaches and managers who evaluate their talent. At the end of spring training, players both from the spring major camp and minor league winter camp are placed by the major league club on the roster of a minor league team. The Director of Player Development and the general manager usually determine the initial assignments for new draftees, who typically begin playing professionally in June after they have been signed to contracts. The farm system is ever-changing, and evaluation of players is a constantly ongoing process. The Director of Player Development and his managers meet or teleconference regularly to discuss how players are performing at each level. Personal development, injuries, and high levels of achievement by players in the classes below all steer a player's movement up and down in the class system.

text: Players will play for the team to which they are assigned for the duration of that season unless they are "called up" (promoted to a higher level), "sent down" (demoted to a lower-class team in the major league club's farm system), or "released" from the farm system entirely. A release from minor-league level used to spell the end of a minor league player's career. In more modern times, released players often sign with independent baseball clubs, which are scouted heavily by major league organizations. Many players get a second or third look from the major league scouts if they turn their career around in the independent leagues.

text: Even though minor league players are paid considerably less than their major league counterparts, they are nevertheless paid for their services and are thus considered professional athletes. Minor league salaries vary based on class level and length of season; however, the majority of players make less than $10,000 per season.[13] Baseball cards refer to "pro record" and "pro seasons" as including both major and minor leagues. For this reason, minor league players generally consider it an insult when someone asks when they're going to "get to the pros". More accurately, a player's aim is to reach "The Show" or the "big leagues."

text: Umpires[edit]

text: Umpires at the minor league level are overseen by Minor League Baseball Umpire Development, which is responsible for the training, evaluation, and recommendation for promotion and retention or release of the umpires.[14]

text: The umpires are evaluated eight times a season by the staff of the MiLB Umpire Development, and receive a ranking at mid-season and the end of each year. Based on performance during the year, an umpire may advance in classification when a position opens in-season or during the off-season. Umpire Development holds an annual evaluation course every year in March to evaluate rookie umpires. Participants are normally the best students from the two professional umpire schools (one owned and operated by the same entity). The top students who pass the evaluation course are recommended for the first openings in the Rookie and short season leagues.[15]

text: Any student who wants to work as an umpire must attend a professional umpire training school. The MiLB recognizes two schools for training prospective professional umpires, the Harry Wendelstedt Umpire School and Minor League Baseball Umpire Training Academy, both located in Florida. The Minor League Baseball Umpire Training Academy is owned and operated by Minor League Baseball Umpire Development (MiLBUD), while Wendelstedt is independently owned by MLB Umpire Hunter Wendelstedt. The classes for each school are held for five weeks in January and February. The instructors at these schools are former or present major or minor league umpires. Simply attending one of these schools, however, does not guarantee that the candidate will also be recommended either to the evaluation course or to the openings in the Rookie or short season leagues. Generally, less than 20% of umpire school students move on to the Rookie Evaluation Course.[16]

text: Before the umpire development program was created, the Minor League presidents would recruit umpires directly from the schools. Umpires were then "sold" from league to league by word of mouth through the various league presidents.[17]

text: The umpire development program first started in 1964, when it was decided that a method of recruitment, training and development for umpires of both major and minor leagues was needed. The Umpire Development Program was founded at Baseball's 1964 Winter Meetings in Houston, and it began operating the next year. The program aimed to recruit more athletic, energetic and dedicated individuals who would also have high morals and integrity standards. In 1968, it was decided that the program needed its own umpire training course which would be held each year. The first "Umpire Specialization Course" was held in St. Petersburg, Florida the following year.[18]

text: Presently, the candidates for a job in professional umpiring must meet several requirements in order to be considered. An applicant must have a high school diploma or a G.E.D., must be athletic, and also must have 20/20 vision, though they are permitted to wear glasses or contact lenses.[19] They must also have good communication skills, good reflexes and coordination, and must have trained at one of the two professional umpire schools.

text: On June 21, 2016, the Gulf Coast League hired Jen Pawol, the first female umpire in Minor League Baseball since 2007.[20]

text: Presidents of Minor League Baseball[edit]

text:
Patrick T. Powers, 1901–1909
Michael H. Sexton, 1909–1931
William G. Bramham, 1932–1946
George Trautman, 1947–1963
Phil Piton, 1964–1971
Hank Peters, 1972–1975
Bobby Bragan, 1976–1978
John H. Johnson, 1979–1988
Sal Artiaga, 1988–1991
Mike Moore, 1991–2007
Pat O'Conner, 2008–present

text: Television and radio[edit]

text: Minor League Baseball has a national television contract with CBS Sports Network, which airs 10–15 games on Thursday nights. The arrangement began in 2014 and will continue through the 2015 season.[21] For the 2015 season, select MiLB games will be featured on the American Sports Network.[22] Also, many individual teams have contracts with local over-the-air channels. Games are also occasionally simulcast on MLB Network.

text: MiLB.TV[edit]

text: MiLB.TV is the minor leagues' official online video streaming service, in the vein of Major League Baseball's MLB.tv. The service currently offers every Triple-A game and select games from the other classifications.

text: Radio[edit]

text: Nearly every minor-league team has its own local radio contract, though unlike their major-league counterparts, these generally consist of only one or two individual stations. Minor League Baseball currently has an arrangement with TuneIn to provide free audio streams of virtually every game.[23]

text: Independent baseball[edit]

text: Independent leagues are those professional leagues in the United States and Canada not under the purview of organized Minor League Baseball and the Commissioner of Baseball. Independent baseball existed in the early 20th century and has become prominent again since 1993.[24]

text: Leagues operated mostly autonomously before 1902, when the majority joined the NAPBL. From then until 1915, a total of eight new and existing leagues remained independent. Most joined the National Association after one season of independence. Notable exceptions were the California League, which was independent in 1902 and from 1907–1909, the United States Baseball League, which folded during its independent 1912 season, and the Colonial League, a National Association Member that went independent in 1915 and then folded.[25] Another independent league, the Federal League, played at a level considered major league from 1914–1915.

text: Few independent leagues existed between 1915 and 1993. Major exceptions included the Carolina League and the Quebec-based Provincial League. The Carolina League, based in the North Carolina Piedmont region, gained a reputation as a notorious "outlaw league" during its existence from 1936–1938.[26] The Provincial League had six teams across Quebec and was independent from 1948–1949. Similarly to early 20th-century independent leagues, it joined the National Association in 1950, playing for six more years.[25][27]

text: Independent leagues saw new growth after 1992, after the new Professional Baseball Agreement in organized baseball instituted more stringent revenue and stadium requirements on members.[28] Over the next eight years, at least 16 independent leagues formed, of which six existed in 2002.[25] As of 2016, seven independent leagues are in operation in the U.S. and Canada, compared to 19 in organized Minor League Baseball.

text: List of leagues[edit]

text:
International League
Pacific Coast League
Mexican League[29]

text:
Eastern League
Southern League
Texas League

text:
California League
Carolina League
Florida State League

text:
Midwest League
South Atlantic League

text:
New York–Penn League
Northwest League

text:
Pioneer League
Appalachian League

text:
Arizona League
Gulf Coast League
Dominican Summer League

text:
Arizona Fall League
Australian Baseball League
Colombian Professional Baseball League
Dominican Professional Baseball League
Mexican Pacific League
Puerto Rico Baseball League
Venezuelan Professional Baseball League

text:
American Association
Atlantic League
Can-Am League
Empire Professional Baseball League
Frontier League
Pacific Association
Pecos League
United Shore League

text: Major league affiliations[edit]

text:
Table key

Triple-A
Double-A
Class A-Advanced
Class A
Class A Short Season
Rookie Advanced

International League
Eastern League
Carolina League
South Atlantic League
New York-Penn League
Appalachian League

Pacific Coast League
Texas League
California League
Midwest League
Northwest League
Pioneer League

—

Southern League
Florida State League

—

—

—

text:
Division
Team
Triple-A
Double-A
Class A-Advanced
Class A
Class A Short Season
Rookie Advanced

American League

East
Baltimore Orioles
Norfolk Tides
Bowie Baysox
Frederick Keys
Delmarva Shorebirds
Aberdeen IronBirds

—

Boston Red Sox
Pawtucket Red Sox
Portland Sea Dogs
Salem Red Sox
Greenville Drive
Lowell Spinners

—

New York Yankees
Scranton/Wilkes-Barre RailRiders
Trenton Thunder
Tampa Yankees
Charleston RiverDogs
Staten Island Yankees
Pulaski Yankees

Tampa Bay Rays
Durham Bulls
Montgomery Biscuits
Charlotte Stone Crabs
Bowling Green Hot Rods
Hudson Valley Renegades
Princeton Rays

Toronto Blue Jays
Buffalo Bisons
New Hampshire Fisher Cats
Dunedin Blue Jays
Lansing Lugnuts
Vancouver Canadians
Bluefield Blue Jays

Central
Chicago White Sox
Charlotte Knights
Birmingham Barons
Winston-Salem Dash
Kannapolis Intimidators

—

Great Falls Voyagers

Cleveland Indians
Columbus Clippers
Akron RubberDucks
Lynchburg Hillcats
Lake County Captains
Mahoning Valley Scrappers

—

Detroit Tigers
Toledo Mud Hens
Erie SeaWolves
Lakeland Flying Tigers
West Michigan Whitecaps
Connecticut Tigers

—

Kansas City Royals
Omaha Storm Chasers
Northwest Arkansas Naturals
Wilmington Blue Rocks
Lexington Legends

—

Burlington Royals
Idaho Falls Chukars

Minnesota Twins
Rochester Red Wings
Chattanooga Lookouts
Fort Myers Miracle
Cedar Rapids Kernels

—

Elizabethton Twins

West
Houston Astros
Fresno Grizzlies
Corpus Christi Hooks
Buies Creek Astros
Quad Cities River Bandits
Tri-City ValleyCats

—

Los Angeles Angels
Salt Lake Bees
Mobile BayBears
Inland Empire 66ers
Burlington Bees

—

Orem Owlz

Oakland Athletics
Nashville Sounds
Midland RockHounds
Stockton Ports
Beloit Snappers
Vermont Lake Monsters

—

Seattle Mariners
Tacoma Rainers
Arkansas Travelers
Modesto Nuts
Clinton LumberKings
Everett AquaSox

—

Texas Rangers
Round Rock Express
Frisco RoughRiders
Down East Wood Ducks
Hickory Crawdads
Spokane Indians

—

National League

East
Atlanta Braves
Gwinnett Braves
Mississippi Braves
Florida Fire Frogs
Rome Braves

—

Danville Braves

Miami Marlins
New Orleans Baby Cakes
Jacksonville Jumbo Shrimp
Jupiter Hammerheads
Greensboro Grasshoppers
Batavia Muckdogs

—

New York Mets
Las Vegas 51s
Binghamton Rumble Ponies
St. Lucie Mets
Columbia Fireflies
Brooklyn Cyclones
Kingsport Mets

Philadelphia Phillies
Lehigh Valley IronPigs
Reading Fightin' Phils
Clearwater Threshers
Lakewood BlueClaws
Williamsport Crosscutters

—

Washington Nationals
Syracuse Chiefs
Harrisburg Senators
Potomac Nationals
Hagerstown Suns
Auburn Doubledays

—

Central
Chicago Cubs
Iowa Cubs
Tennessee Smokies
Myrtle Beach Pelicans
South Bend Cubs
Eugene Emeralds

—

Cincinnati Reds
Louisville Bats
Pensacola Blue Wahoos
Daytona Tortugas
Dayton Dragons

—

Billings Mustangs

Milwaukee Brewers
Colorado Springs Sky Sox
Biloxi Shuckers
Carolina Mudcats
Wisconsin Timber Rattlers

—

Helena Brewers

Pittsburgh Pirates
Indianapolis Indians
Altoona Curve
Bradenton Marauders
West Virginia Power
West Virginia Black Bears
Bristol Pirates

St. Louis Cardinals
Memphis Redbirds
Springfield Cardinals
Palm Beach Cardinals
Peoria Chiefs
State College Spikes
Johnson City Cardinals

West
Arizona Diamondbacks
Reno Aces
Jackson Generals
Visalia Rawhide
Kane County Cougars
Hillsboro Hops
Missoula Osprey

Colorado Rockies
Albuquerque Isotopes
Hartford Yard Goats
Lancaster JetHawks
Asheville Tourists
Boise Hawks
Grand Junction Rockies

Los Angeles Dodgers
Oklahoma City Dodgers
Tulsa Drillers
Rancho Cucamonga Quakes
Great Lakes Loons

—

Ogden Raptors

San Diego Padres
El Paso Chihuahuas
San Antonio Missions
Lake Elsinore Storm
Fort Wayne TinCaps
Tri-City Dust Devils

—

San Francisco Giants
Sacramento River Cats
Richmond Flying Squirrels
San Jose Giants
Augusta GreenJackets
Salem-Keizer Volcanoes

—

text: Team rosters[edit]

text: Awards[edit]

text: MiLBY Awards[edit]

text: The Minor League Baseball Yearly (MiLBY) Awards (formerly "This Year in Minor League Baseball Awards") are given in nine categories. In five categories (Best Starter, Best Hitter, Best Reliever, Best Game, and Best Team), winners are selected in each of the five levels of minor-league baseball (Triple-A, Double-A, Class A-Advanced, Class A, and Class A Short Season). In three categories (Play of the Year, Moment of the Year, and Homer of the Year), one overall winner is chosen for all of minor-league baseball. In the remaining category (Promo of the Year), there are overall winners in each of five subcategories: Best Promotion (of all types), Best Theme Night, Best Giveaway, Best Celebrity Appearance, and Best Miscellaneous Promotion.

text: Other player awards[edit]

text:
MiLB J.G. Taylor Spink Award (Topps/Minor League Player of the Year)[30][31]
MiLB George M. Trautman Awards (Topps Player of the Year) (in each of 16 domestic minor leagues)[32]
MiLB Joe Bauman Home Run Award[33]

text: Major awards[edit]

text:
John H. Johnson President's Award (1974) – given each year, MiLB's top award recognizes "the complete baseball franchise—based on franchise stability, contributions to league stability, contributions to baseball in the community, and promotion of the baseball industry."[34][35]
Rawlings Woman Executive of the Year (1976) – given each year to a woman in MiLB for exceptional contributions to her club, her league, or baseball.[34][36]
Warren Giles Award (1984) – given each year to a league president for outstanding service.[34][36][37]
King of Baseball (1951) – given annually in recognition of longtime dedication and service to professional baseball.[34]
Larry MacPhail Award (1966) – given annually in recognition of team promotions.[34][38]
Sheldon "Chief" Bender Award (2008) – given to a person with distinguished service who has been instrumental in player development.[34]
Mike Coolbaugh Award (2008) – given to someone who has shown an outstanding baseball work ethic, knowledge of the game, and skill in mentoring young players on the field.[34]

text: Top 100 teams[edit]

text: During its centennial celebration in 2001, Minor League Baseball compiled a list of the 100 best minor-league baseball teams of the century.[39]