Universal Motor MCQ :: Single Phase Induction Motor

11. Calculate the heat absorbed by a 3 Ω resistor when 6 V is applied across it.

A. 12 W
B. 10 W
C. 8 W
D. 11 W

Answer: A

The resistor always absorbs active power and dissipates it in the form of heat.

Power absorbed by a 3 Ω resistor is 6×6÷3=12 W.   

 

12. What is the unit of power?

A. Joule/sec
B. Joule/sec2
C. Joule/sec3
D. Joule/sec4

Answer: A

Power is defined as the rate at which work is done. The ratio of energy and time is power. It is expressed in Watt or Joule/sec.   

 

13. Convert 20 ℃ into Fahrenheit.

A. 68 ℉
B. 58 ℉
C. 78 ℉
D. 48 ℉

Answer: A

Temperature can be expressed in Celsius and Fahrenheit. The Standard unit of the temperature is the Kelvin(K).

(20℃ × 9/5) + 32 = 68℉.   

 

14. Convert 50℉ into Celsius.

A. 20 ℃
B. 10 ℃
C. 30 ℃
D. 40 ℃

Answer: A

Temperature can be expressed in Celsius and Fahrenheit. The basic unit of temperature in SI is the Kelvin. The formula used is

(50℉ − 32) × 5/9 = 10℃.   

 

15. Which duty cycle has on load and off-loads period?

A. Intermittent duty
B. Short-time duty
C. Continuous duty with constant load
D. Continuous duty with variable load

Answer: A

The intermittent duty cycle has frequent on-load and off-loads periods. The on-load period and off-loads periods are too short to achieve steady-state thermal condition.   

 

16. Which motor is preferred for Jaw crushers?

A. WRIM
B. SCIM
C. Belt slip ring IM
D. DC shunt motor

Answer: C

Belt slip ring IM is preferred for the operation of Jaw crushers. A high starting is provided by the Belt ring IM. Slip rings are used to add external resistance.   

 

17. A high starting torque is offered by the Belt Conveyors.

A. True
B. False

Answer: A

The Belt Conveyors can provide continuous-flow transportation. The amount of material transported on a conveyor system depends upon belt speed, and belt width.   

 

18. Which starting method is the worst method in Induction motor?

A. Direct online starting
B. Autotransformer starting
C. Reactance starting
D. Star-Delta starting

Answer: C

The Reactance starting method is the worst method in an Induction motor. It uses the concept of the potential divider. The losses are very high in the case of the Reactance starting method.   

 

19. Induction motor is also known as __________

A. Frequency changer
B. Frequency remover
C. Time period remover
D. DC machine

Answer: A

The Induction motor is also known as a frequency changer. The stator frequency can be changed using the slip concept. The rotor frequency of IM is slip×(stator frequency).   

 

20. The capacity of the Crane is expressed in terms of tonnes.

A. True
B. False

Answer: A

Cranes are used to carry or lift heavy loads. The capacity of a Crane is expressed in terms of tonnes. 1 tonne is equal to 1000 Kg.   

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