Which type of motor uses run windings only?

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Multiple Choice

Which type of motor uses run windings only?

In motors, starting torque often comes from creating a phase difference in windings. Three-phase motors get that rotating magnetic field directly from the three-phase supply, without needing a separate starting winding or capacitor. The three windings are energized with currents that are 120 degrees apart, which naturally sums to a rotating magnetic field that the rotor can lock onto and follow right away. Because this spinning field is produced by the run windings of a three-phase stator for operation, there isn’t a separate start winding required. In contrast, other options rely on additional starting components: single-phase PSC motors use a start winding with a capacitor to create the necessary phase shift, shaded pole motors use a shading coil to generate a secondary flux for starting, and DC motors use distinct armature and field windings (with a commutator) to develop torque. So the type that uses run windings only is the three-phase motor.

In motors, starting torque often comes from creating a phase difference in windings. Three-phase motors get that rotating magnetic field directly from the three-phase supply, without needing a separate starting winding or capacitor. The three windings are energized with currents that are 120 degrees apart, which naturally sums to a rotating magnetic field that the rotor can lock onto and follow right away. Because this spinning field is produced by the run windings of a three-phase stator for operation, there isn’t a separate start winding required.

In contrast, other options rely on additional starting components: single-phase PSC motors use a start winding with a capacitor to create the necessary phase shift, shaded pole motors use a shading coil to generate a secondary flux for starting, and DC motors use distinct armature and field windings (with a commutator) to develop torque. So the type that uses run windings only is the three-phase motor.

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