HVACR ELECTRICAL-CMS, 11 of 14,
Motor/Compressors Correct Questions
And Answers 2025.
The induction motor derives its name from the fact that ac voltages are induced in the ___________ by
the rotating magnetic field of the ___________ - Answer - Rotor, stator
The speed of an ac motor depends on the _____________ and the __________________ - Answer - The
frequency of the current supplied to it and the number of poles of the motor.
Is the speed of the rotor greater than or less than the speed of the rotating field? What is the difference
called? - Answer - The speed is less, it is called slip
Calculate the percent of slip for a motor with a synchronous speed of 3,600 rpm and a rotor speed of
3,400 rpm. - Answer - S = ((Ss - Sr)/Ss) X 100 (3600 - 3400/3600) X 100 = 200/3600 X 100 = 5.55%
What are the two types of motor windings in a simple ac motor? - Answer - Run and Start windings
Do shaded-pole motors have a high or low starting torque? - Answer - Low
A split-phase motor uses either a(n) ___________or a(n) ________to switch the start winding in and out
of the circuit. - Answer - Centrifugal switch or a current relay
What kind of motors are commonly used in residential refrigerator compressor units? - Answer - Split
phase motors
The type of motor in which the capacitor is never taken out of the circuit is called a(n)
___________motor. - Answer - Permanent split capacitor motor
, In a capacitor-start, induction-run motor, the capacitor is wired in _____________ with the start
winding. - Answer - Series
Which has a higher starting torque, the capacitor-start, induction-run motor or the capacitor-start,
capacitor-run motor? - Answer - capacitor-start, capacitor-run motor
What type of motors are generally used in large commercial air conditioning applications? - Answer - 3
phase
What is a simple way to reverse the direction of rotation of a three-phase motor? - Answer - Interchange
any two leads
The windings of a three-phase motor may be connected in a(n) _________ configuration or a(n)
__________ configuration. - Answer - Delta, wye
When is it desirable to use "across-the-line" starting? - Answer - The inrush or locked rotor amperage is
low enough to make the use of only one starting device economical.
What type of starting method is required for large compressors and large current demands? - Answer -
Part winding start
A dc motor whose motion consists of discrete increments, instead of continuous rotation, is called a(n)
__________motor. - Answer - step
Most motors are designed to operate in an ambient temperature of not more than ____________ -
Answer - 40 C or 104 F
The voltage at which a magnetically operated device starts to operate is called the _______________ -
Answer - Pickup voltage
20. The service factor of a motor measures its designed ______________ - Answer - Overload capacity
Motor/Compressors Correct Questions
And Answers 2025.
The induction motor derives its name from the fact that ac voltages are induced in the ___________ by
the rotating magnetic field of the ___________ - Answer - Rotor, stator
The speed of an ac motor depends on the _____________ and the __________________ - Answer - The
frequency of the current supplied to it and the number of poles of the motor.
Is the speed of the rotor greater than or less than the speed of the rotating field? What is the difference
called? - Answer - The speed is less, it is called slip
Calculate the percent of slip for a motor with a synchronous speed of 3,600 rpm and a rotor speed of
3,400 rpm. - Answer - S = ((Ss - Sr)/Ss) X 100 (3600 - 3400/3600) X 100 = 200/3600 X 100 = 5.55%
What are the two types of motor windings in a simple ac motor? - Answer - Run and Start windings
Do shaded-pole motors have a high or low starting torque? - Answer - Low
A split-phase motor uses either a(n) ___________or a(n) ________to switch the start winding in and out
of the circuit. - Answer - Centrifugal switch or a current relay
What kind of motors are commonly used in residential refrigerator compressor units? - Answer - Split
phase motors
The type of motor in which the capacitor is never taken out of the circuit is called a(n)
___________motor. - Answer - Permanent split capacitor motor
, In a capacitor-start, induction-run motor, the capacitor is wired in _____________ with the start
winding. - Answer - Series
Which has a higher starting torque, the capacitor-start, induction-run motor or the capacitor-start,
capacitor-run motor? - Answer - capacitor-start, capacitor-run motor
What type of motors are generally used in large commercial air conditioning applications? - Answer - 3
phase
What is a simple way to reverse the direction of rotation of a three-phase motor? - Answer - Interchange
any two leads
The windings of a three-phase motor may be connected in a(n) _________ configuration or a(n)
__________ configuration. - Answer - Delta, wye
When is it desirable to use "across-the-line" starting? - Answer - The inrush or locked rotor amperage is
low enough to make the use of only one starting device economical.
What type of starting method is required for large compressors and large current demands? - Answer -
Part winding start
A dc motor whose motion consists of discrete increments, instead of continuous rotation, is called a(n)
__________motor. - Answer - step
Most motors are designed to operate in an ambient temperature of not more than ____________ -
Answer - 40 C or 104 F
The voltage at which a magnetically operated device starts to operate is called the _______________ -
Answer - Pickup voltage
20. The service factor of a motor measures its designed ______________ - Answer - Overload capacity
