Design of Electrical Machine 3

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Electrical Engineering MCQ Question Papers: Campus Placement

Subject: Design of Electrical Machine 3

Part 3: List for questions and answers of Design of Electrical Machine

 

Q1. Gaseous insulating material

a) Teflon

b) Sulphur hexafluoride

c) Stealite

d) Phologopite mica

 

Q2. Silver finds application generally as

a) Contact material

b) Fusing material

c) Low temperature insulating material

d) None of the above

 

Q3. When I is the current in amperes, the temperature rise at which fuse wire will melt is proportional to

a) I

b) I 2

c) 1/ I

d) 1/ I2

 

Q4. The fusing current depends on

a) Diameter of fuse wire

b) Number of strands of wire

c) Length of the fuse wire

d) All of the above

 

Q5. Class H insulation is normally used in

a) Traction motors

b) Submersible pump motors

c) Single phase motors

d) Dc motors

 

Q6. An ideal liquid insulating material should have low

a) Heat conductivity

b) Dielectric strength

c) Mechanical strength

d) Volatility 

 

Q7. The electric breakdown strength of an instating material depends on

a) Composition of the material

b) Thickness of the material

c) Time of application of voltage

d) All of the above

 

Q8. When V is the voltage applied across the insulation, the dielectric loss for an insulating material will be proportional to

a) V

b) V2

c) 1/ V

d) 1/ V2

 

Q9. When ? the dielectric loss angle, the value of tan? increases with

a) Decrease in temperature

b) Presence of moisture

c) Voltage

d) All of the above

 

Q10. Which has lowest dielectric strength

a) Cotton

b) Empire cloth

c) Porcelain

d) Mica

 

Q11. Silicon steel E330 indicates that

a) It has 33% silicon

b) It has normal specific loss at 50 Hz

c) It is cold rolled grain oriented

d) All of the above

 

Q12. Which of the following silicon steel will have least specific lose ?

a) E11

b) E42

c) E31

d) E41 

 

Q13. In silicon steel designation like E320 the first figure 3 indicates

a) The percentage of silicon

b) The specific loss at 50 Hz

c) The specific lose at 100 Hz

d) The grain oriented cold rolled variety

 

Q14. In silicon steel designation like E320 , the second figure 2 represent

a) Specific loss

b) Direction of grain orientation

c) Magnetic variety

d) Non-magnetic variety

 

Q15. In high nickel alloys the percentage of nickel is

a) 5 to 10 percent

b) 10 to 20 percent

c) 30 to 50 percent

d) 70 to 80 percent

 

Q16. Pumps, blowers and fans are usually called for

a) Continuous duty

b) Short time duty

c) Intermittent periodic duty

d) Intermittent periodic duty with starting and braking

 

Q17. Which of the following is normally called for continuous duty with starting and braking ?

a) Machine tools

b) Compressors

c) Sirens

d) Escalators

 

Q18. In lap windings, the equalizer rings arc used to save

a) Armature winding from carrying circulating currents

b) Commutator from carrying circulating currents

c) Brushes from carrying circulating currents

d) Armature core from eddy currents 

 

Q19. Which of the following calls for intermittent duty with starting and braking ?

a) Pumps

b) Conveyors

c) Wind lasses

d) Cranes

 

Q20. For a 5 kW DC motor the number of slots per pole should be

a) 4

b) 8

c) 12

d) 16 

 

Part 3: List for questions and answers of Design of Electrical Machine

 

Q1. Answer: b

 

Q2. Answer: a

 

Q3. Answer: b

 

Q4. Answer: d

 

Q5. Answer: a

 

Q6. Answer: d

 

Q7. Answer: d

 

Q8. Answer: b

 

Q9. Answer: b

 

Q10. Answer: a

 

Q11. Answer: c

 

Q12. Answer: a

 

Q13. Answer: a

 

Q14. Answer: a

 

Q15. Answer: d

 

Q16. Answer: a

 

Q17. Answer: a

 

Q18. Answer: c

 

Q19. Answer: d

 

Q20. Answer: b