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With increasing power output, three-phase motors have preferable characteristics to single-phase motors; the latter not being available in sizes over 15 hp (11 kW) and, though available, rarely seen larger than 5 hp (3.7 kW). (Three-phase motors have higher efficiency, reduced complexity, with regards to starting, and three-phase power is ...
A motor capacitor [1] [2] is an electrical capacitor that alters the current to one or more windings of a single-phase alternating-current induction motor to create a rotating magnetic field. [ citation needed ] There are two common types of motor capacitors, start capacitor and run capacitor (including a dual run capacitor ).
The number of magnetic poles, , is the number of north and south poles per phase. For example; a single-phase motor with 3 north and 3 south poles, having 6 poles per phase, is a 6-pole motor. A three-phase motor with 18 north and 18 south poles, having 6 poles per phase, is also a 6-pole motor.
There is no defined minimum output, however, it is generally accepted that a motor with a frame size of less than 35mm square can be referred to as a 'micro-motor'. Fractional-horsepower electric motors are exempt from the US Energy Policy Act of 2005 and the new EN 60034-30:2009 [ 1 ] ruling of European directive 2005/32/EC [ 2 ] concerning ...
The coils may span several slots in the stator core, making it tedious to count them. For a 3-phase motor, if you count a total of 12 coil groups, it has 4 magnetic poles. For a 12-pole 3-phase machine, there will be 36 coils. The number of magnetic poles in the rotor is equal to the number of magnetic poles in the stator.
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 ...
The speed and torque characteristics of a wound-rotor motor can be adjusted by changing the external resistance, unlike a squirrel cage motor which has a fixed characteristic. This is useful for speed control of the motor. [1] A wound-rotor motor can be used in several forms of adjustable-speed drive. Common applications include hoists and ...
700 horsepower Brown-Boveri-Déri repulsion motor with 10 poles to be used with 12 kV, 16 2/3 Hz single phase current. Two of these motors were used in the French electric locomotive Midi E3301. A repulsion motor is a type of electric motor which runs on alternating current (AC).