Selection of motors - Electrical Engineering (MCQ) questions and answers

1)   What designation is used for non sparking type of motor?

a. Ex(d)
b. Ex(p)
c. Ex(N)
d. Ex(e)
Answer  Explanation 

ANSWER: Ex(N)

Explanation:
No explanation is available for this question!
2)   Which of the standards are applicable for designing induction motors?

a. Indian standards
b. British standards
c. International electro technical commissions standards
d. All of these
e. None of these
Answer  Explanation 

ANSWER: All of these

Explanation:
No explanation is available for this question!
3)   Which among these is not a type of single phase AC motor?

a. Split phase
b. Synchronous motor
c. Capacitor start
d. Capacitor run
Answer  Explanation 

ANSWER: Synchronous motor

Explanation:
No explanation is available for this question!
4)   What is / are the criteria used for choosing different types of frame for rotary electrical machines?

a. The bearing type
b. The form of stator
c. The position of shaft
d. All of these
Answer  Explanation 

ANSWER: All of these

Explanation:
No explanation is available for this question!
5)   Which motor is preferred for cement industry?

a. Squirrel cage motor
b. Synchronous motor
c. Universal motor
d. DC series motor
Answer  Explanation 

ANSWER: Synchronous motor

Explanation:
No explanation is available for this question!
6)   Which among the following factors affect the cost of motor?

i. Reliability  and Availability
ii. Installation & Commissioning charges
iii. Running cost, KVAr
iv. Depression formula used


a. i & ii
b. ii, iii, iv
c. i, ii, iv
d. i, ii, iii & iv
Answer  Explanation 

ANSWER: i, ii, iii & iv

Explanation:
No explanation is available for this question!
7)   What is the value of R and C in RC surge suppressor?

a. R = 1000 Ω C = 0.01 μ F
b. R = 100 Ω C = 0.1 μ F
c. R = 1000 Ω C = 0.1 μ F
d. R = 100 Ω C = 0.01 μ F
Answer  Explanation 

ANSWER: R = 100 Ω C = 0.1 μ F

Explanation:
No explanation is available for this question!
8)   Which relation governs the fault level of the supply in LV motors?
If K – factor for number of motors started simultaneously started on the same bus
Sa – 3 phase fault level
M – Rated MW of any one motor


a. Sa = K * 50 * M
b. Sa = K * 20 * M
c. Sa = K * 60 * M
d. Sa = K * 80 * M
Answer  Explanation 

ANSWER: Sa = K * 50 * M

Explanation:
No explanation is available for this question!
9)   On what factors is the rated voltage selected for an induction motor?

a. Motor rating
b. Starting current
c. Fault levels of supply
d. All of these
e. None of these
Answer  Explanation 

ANSWER: All of these

Explanation:
No explanation is available for this question!
10)   What is the maximum permissible voltage drop that can be sustained while starting an electrical rotating machine?

a. 15 – 20 % of the rated voltage
b. 20 – 25 % of the rated voltage
c. 5 – 10 % of the rated voltage
d. 0 – 5 % of the rated voltage
Answer  Explanation 

ANSWER: 15 – 20 % of the rated voltage

Explanation:
No explanation is available for this question!

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