Single Phase Motors Objective 1 Flashcards
Single phase motors are more efficient than 3 phase motors of comparable horsepower true or false.
False
Just more practical in residential or commercial applications.
Most single phase motors fall into the
_______ to_______HP range.
1/6 to 3/4
Single phase split phase induction motors are classified by.
The way the stater windings are used for starting and running.
List the main components of the resistance split phase motor
Frame, Centralfugal switch, stator and rotor.
What does the centrifugal switch do?
Disconnects the start winding at approximately 75% of the rated speed.
In order for the motors start, the current in the start winding must be.
Out of phase with the current in the main winding.
Typical phase placement between start and main winding current and the resistance split phase motor is.
25 to 30°.
While a resistance split phase motors running after the centrifugal switch has opened. The cross-field effect results in the motor stimulating A.
2 phase rotating magnetic field of 90° displacement.
There resistance split phase induction motor has low starting torque and high. Starting current, true or false.
True
A resistance split phase motor is reversible if the connections to the start winding are brought out to the connection box true or false.
True
Reversible Change his direction at stand still.
What are the 4 types of single phase motors mentioned in the module?
Resistance split phase motor capacitor start motor permanent split capacitor motor and 2 value capacitor motor.
What other methods of start winding cutout can be used in place of a centrifugal switch.
Current sensitive relays and electronic switching devices.
What is the typical slip percentage of a resistance start induction motor?
4 to 6%.
What is the synchronous speed formula?
Ns=(f×120)÷p
P= poles
f= frequency
Ns= synchronous speed
What is the starting torque of a resistance split phase motor?
125 to 150% of running torque.
