Transformers

1. Delta/star transformer works satisfactorily when

load is balanced only
load is unbalanced only
on balanced as well as unbalanced loads
none of the above

Detailed SolutionDelta/star transformer works satisfactorily when

2. In case of a double cage induction motor, the inner cage has

high inductance arid low resistance
low inductance and high resistance
low inductance and low resistance
high inductance and high resistance

Detailed SolutionIn case of a double cage induction motor, the inner cage has

3. Which of the following does not change in a transformer?

Current
Voltage
Frequency
All of the above

Detailed SolutionWhich of the following does not change in a transformer?

4. Which of the following does not change in an ordinary transformer?

Frequency
Voltage
Current
Any of the above

Detailed SolutionWhich of the following does not change in an ordinary transformer?

5. A no-load test is performed on a transformer to determine

core loss
copper loss
efficiency
magnetising current E. magnetising current and loss

Detailed SolutionA no-load test is performed on a transformer to determine

6. The secondary winding of which of the following transformers is always kept closed?

Step-up transformer
Step-down transformer
Potential transformer
Current transformer

Detailed SolutionThe secondary winding of which of the following transformers is always kept closed?

7. A transformer transforms

voltage
current
power
frequency

Detailed SolutionA transformer transforms

8. The transformer ratings are usually expressed in terms of

volts
amperes
kW
kVA

Detailed SolutionThe transformer ratings are usually expressed in terms of

9. The starting torque of a squirrel-cage induction motor is

low
negligible
same as full-load torque
slightly more than full-load torque

Detailed SolutionThe starting torque of a squirrel-cage induction motor is

10. The path of the magnetic flux in transformer should have

high reluctance
low reactance
high resistance
low resistance

Detailed SolutionThe path of the magnetic flux in transformer should have

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