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The poles can be varied at a ratio of 1:2 and thus the speed can be varied at 2:1. [7] [8] [9] Normally, the electrical configuration of windings is varied from a delta connection (Δ) to a double star connection (YY) configuration in order to change the speed of the motor for constant torque applications, such as the hoists in cranes.
The motor constant is winding independent (as long as the same conductive material is used for wires); e.g., winding a motor with 6 turns with 2 parallel wires instead of 12 turns single wire will double the velocity constant, , but remains unchanged.
The switched reluctance motor (SRM) is a type of reluctance motor. Unlike brushed DC motors , power is delivered to windings in the stator (case) rather than the rotor . This simplifies mechanical design because power does not have to be delivered to the moving rotor, which eliminates the need for a commutator .
The switched reluctance motor (SRM) is a type of reluctance motor. Unlike brushed DC motors , power is delivered to windings in the stator (case) rather than the rotor . This simplifies mechanical design because power does not have to be delivered to the moving rotor, which eliminates the need for a commutator .
The motor speed varies as a non-linear function of load torque and armature current; current is common to both the stator and rotor yielding current squared (I^2) behavior [citation needed]. A series motor has very high starting torque and is commonly used for starting high inertia loads, such as trains, elevators or hoists. [ 2 ]
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 ...
Michael Faraday made a Homopolar motor in 1831. Superconducting DC homopolar machines use superconductors in their stationary field windings and normal conductors in their rotating pickup winding. In 2005 the General Atomics company received a contract for the creation of a large low speed superconducting homopolar motor for ship propulsion. [1]
The stationary (stator) windings of an outrunner motor are excited by conventional DC brushless motor controllers. A direct current (switched on and off at high frequency for voltage modulation) is typically passed through three or more non-adjacent windings together, and the group so energized is alternated electronically based upon rotor position feedback.