Unit 34 Single Phase Motors

Number of poles Frequency of applied voltage

Two factors determine the synchronous speed of a split phase motor.

The Holtz motor operates at ____ RPM.

1200

The Warren motor operates at _____ RPM.

3600

A two-phase power system has two voltages that are _____ out of phase.

90°

In a universal motor, inductive compensation can be used when the motor is connected to _____.

AC only

90 degrees out of phase with each other

Maximum torque is produced when current between the start winding and run winding are _______

120 or 24 volts

Single phase motors are generally designed to run on _____

Home appliances such as air conditioners, well pumps, refridgerators and fans

Single phase motors are used almost exclusivly to run _____

Resistance start induction run Capacitor start induction run Capacitor start capacitor run

Split phase motors fall into three general classifications

A rotating magnetic field

Split phase motors operate on the principal of _____.

A two phase power system

Split phase motors split the current flow through two separate windings to simulate _______

Run winding

The ______ winding is made of relatively large wire and is placed in the bottom of the stator core.

Start winding

The ______ winding is made of small wire and is placed near the top of the stator core

In single-phase motors such as the resistance start induction-run motor, the start winding is disconnected by the _____.

centrifugal switch

The universal motor has a wound armature and brushes like an AC motor, as well as an added component, the _____.

compensating winding

The consequent-pole motor is used where _____ running torque must be maintained at different speeds.

high

A single-phase synchronous motor is sometimes referred to as a(n) _____ motor.

hysteresis

Multispeed fan motors achieve multiple speeds by inserting additional _____ in series with the run winding.

inductance

In the shaded-pole induction motor, the direction of rotation of the magnetic field is determined by the _____.

magnetic field strength

In a universal motor, setting the brushes to the neutral plane can be done by connecting voltage to the armature, a voltmeter to the series field, and adjusting the brush position for a _____ reading on the voltmeter.

minimum

The output shaft of a stepping motor _____.

moves through a specific angle for each input pulse

A(n) _____ motor operates on the principle that like magnetic poles repel.

repulsion

Split-phase motors operate on the principle of a _____ magnetic field.

rotating

The _____ winding is made of a few turns of large wire and is located at the bottom of the stator core of a split-phase motor.

run

Conductive compensation is accomplished by connecting the compensating winding in _____ with the armature.

series

In the shaded-pole induction motor, the shading coil acts like a transformer with a(n) _____ secondary winding.

shorted

The _____ winding is made of many turns of small wire and is located at the top of the stator core of a split-phase motor.

start

What is a special type of motor designed to operate with the rotor stalled without damage to the motor?

torque motor

The _____ motor can operate on either AC or DC voltage.

universal

The start winding and the run winding

The stator of a split phase motor contains two separate windings

The strength of the magnetic field of the stator Strength of the magnetic field of the rotor Phase angle difference between current in the start and run winding

The amount of torque produced by a split phase motor is determined by three factors

Lags the applied voltage due to inductive reactance

The current flow in the run winding of a split phase motor _______ the applied voltage due to ______

More inductive reactance and less resistance

The run winding is made of larger wire placed near the bottom of the core, this gives it more _______ and less ______

More resistance and less inductive reactance

The start winding is made of smaller wire, so it has more ________ and less ________.

Synchronous speed

The speed of the rotating magnetic field is called _____

In a motor that has a rotating magnetic field, the speed of that magnetic field is referred to as the _____.

synchronous speed