Search results
Results from the WOW.Com Content Network
Cogging torque of electrical motors is the torque due to the interaction between the permanent magnets of the rotor and the stator slots of a permanent magnet machine. It is also known as detent or no-current torque. This torque is position dependent and its periodicity per revolution depends on the number of magnetic poles and the number of ...
Within the squirrel-cage rotor is a freely rotating permanent magnet rotor, which is locked in with rotating field from the stator. The effect of the inner rotor is to reenforce the field from the stator. [ 1 ]
A common example is "cogging torque" due to slight asymmetries in the magnetic field generated by the motor windings, which causes variations in the reluctance depending on the rotor position. This effect can be reduced by careful selection of the winding layout of the motor, or through the use of realtime controls to the power delivery.
Most motors exhibit positional torque ripple known as cogging torque. In high-speed motors, this effect is usually negligible, as the frequency at which it occurs is too high to significantly affect system performance; direct-drive units will suffer more from this phenomenon unless additional inertia is added (i.e. by a flywheel ) or the system ...
The rotor is made of permanent magnet. Small synchronous motor with integral stepdown gear from a microwave oven A synchronous electric motor is an AC electric motor in which, at steady state , [ 1 ] the rotation of the shaft is synchronized with the frequency of the supply current ; the rotation period is exactly equal to an integer number of ...
Schematic of a permanent magnet motor using brushes and magnets in the stator. A permanent magnet motor is a type of electric motor that uses permanent magnets for the field excitation and a wound armature. The permanent magnets can either be stationary or rotating; interior or exterior to the armature for a radial flux machine or layered with ...
The rotor however has no magnets or coils attached. It is a solid salient-pole rotor (having projecting magnetic poles) made of soft magnetic material, typically laminated steel. When power is applied to a stator winding, the rotor's magnetic reluctance creates a force that attempts to align a rotor pole with the nearest stator pole.
A reluctance motor is a type of electric motor that induces non-permanent magnetic poles on the ferromagnetic rotor. The rotor does not have any windings. It generates torque through magnetic reluctance. Reluctance motor subtypes include synchronous, variable, switched and variable stepping.