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A growler is an electrical device primarily used for testing a motor for shorted coils. A growler consists of a coil of wire wrapped around an iron core and connected to a source of alternating current. When placed on the armature or stator core of a motor the growler acts as the primary of a transformer and the armature coils act as the ...
A DC armature of a miniature motor (or generator) An example of a triple-T armature A partially-constructed DC armature, showing the (incomplete) windings. In electrical engineering, the armature is the winding (or set of windings) of an electric machine which carries alternating current. [1]
A DC motor is an electrical motor that uses direct current (DC) to produce mechanical force. The most common types rely on magnetic forces produced by currents in the coils. Nearly all types of DC motors have some internal mechanism, either electromechanical or electronic, to periodically change the direction of current in part of the motor.
The DC motor's input voltage must overcome the counter emf as well as the voltage drop created by the armature current across the motor resistance, that is, the combined resistance across the brushes, armature winding and series field winding, if any: V m = E b + R m I a [8] [9]
In a motor, the armature current causes the fixed magnetic field to exert a rotational force, or a torque, on the winding to make it turn. In a generator, the mechanical torque applied to the shaft maintains the motion of the armature winding through the stationary magnetic field, inducing a current in the winding.
A DC motor consists of two parts: a rotor and a stator. [3] The stator consists of field windings while the rotor (also called the armature) consists of an armature winding. [4] When both the armature and the field windings are excited by a DC supply, current flows through the windings and a magnetic flux proportional to the current is produced ...
Most [note 1] DC field coils generate a constant, static field. Most three-phase AC field coils are used to generate a rotating field as part of an electric motor. Single-phase AC motors may follow either of these patterns: Small motors are usually universal motors, like the brushed DC motor with a commutator, but run from AC.
A compensation winding in a DC shunt motor is a winding in the field pole face plate that carries armature current to reduce stator field distortion.Its purpose is to reduce brush arcing and erosion in DC motors that are operated with weak fields, variable heavy loads or reversing operation such as steel-mill motors.