Single Phase Motors

Many split-phase motors are designed for operation on ____

120V or 240V

A brush-lifting motor uses a radial commutator, and weights are mounted at the front of the armature. When the motor reaches about ____% of full speed, these weights swing outward due to centrifugal force and cause two push rods to act against a spring barrel and short-circuiting necklace.

75

Motors that are not hermetically sealed use a ____ switch to disconnect the start windings from the circuit.

Centrifugal

Stepping motors are devices that convert ____ into mechanical movement.

Electrical impulses

A Warren motor is constructed with a laminated stator core and two coils, which are generally wound for 120 V AC operation.

False

A consequent pole motor is used where high running torque must be maintained at one constant speed

False

Although a capacitor-start induction-run motor has a high starting torque, the motor should not be started more than two times per hour.

False

There are three basic repulsion motors: repulsion motor, repulsion-start ____ motor, and repulsion-induction motor.

Induction-run

The direction of rotation for a split-phase motor is determined by the direction of rotation of the magnetic field created by the run and start windings when the motor ____.

Is first started

The stator of a split-phase motor contains two separate windings, the start winding and the ____ winding.

Run

Single-phase ____ motors operate on the principle of a rotating magnetic field developed by a shaded-pole stator. Although they will operate at synchronous speed, they do not require DC excitation current.

Synchronous

A repulsion-start induction-run motor starts as a repulsion motor but runs as a squirrel-cage motor.

True

Although a repulsion motor does not operate on the principle of a rotating magnetic field, it is an induction motor. When AC power is connected to the stator winding, a magnetic field with alternating polarities is produced in the poles.

True

In a split-phase motor, synchronous speed is determined by the same two factors that determined the synchronous speed for a three-phase motor: number of stator poles per phase and frequency of the applied voltage.

True

Multispeed fan motors have been used for many years and are generally wound for ____ steps of speed and operate fans and squirrel-cage blowers.

Two to five

The speed of a shaded-pole induction motor is determined by the same factors that determine the synchronous speed of other induction motors—____ and number of stator poles.

Frequency

When stepping motors are used as two-phase synchronous motors, they can start, stop, or reverse direction of rotation virtually instantly. The motor will start within about 1-1/2 cycles of the applied voltage and will stop within 5-25 ms.

True