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
