TS ECET EEE 2016-9

1.A 600 V DC motor a 60 k W load at 900 rpm. If the motor efficiency is 85% determine the current drawn from the supply

A. 117 A
B. 130A
C. 90A
D. 150A

Answer : 117 A
Explain:-

2. A DC machine has maximum efficiency when

A. Variable losses = mechanical losses
B. Variable losses = constant losses
C. Mechanical losses = copper losses
D. Windage and friction losses = copper losses

Answer : Variable losses = constant losses
Explain:-

3. In a DC generator the magnetic neutral axis coincides with the geometrical neutral axis when

A. There is no load on the generator
B. the generator runs on full load
C. The generator runs on overload
D. The generator runs on designed speed

Answer : There is no load on the generator
Explain:-

4. The most efficient form of damping used in electrical measuring instruments is

A. Air friction damping
B. Fluid friction damping
C. Eddy current damping
D. Hysteresis damping

Answer : Eddy current damping
Explain:-

5. Permanent magnet moving coil instruments can measure

A. All AC quantities
B. DC quantities only
C. Both AC and DC quantities
D. Sinusoidal AC quantity only

Answer : DC quantities only
Explain:-

6. Energy meter may be classified as

A. Indicating Instrument
B. Recording Instrument
C. Integrating Instrument
D. deflecting instrument

Answer : Integrating Instrument
Explain:-

7. The secondary of current transformer is

A. Never left short circuited
B. Never left open circuited
C. Always kept open circuited
D. Always be used as voltage transformer

Answer : Never left open circuited
Explain:-

8. If an Ammeter is connected like a Voltmeter, across the load circuit

A. The meter reading will be too low
B. Almost no current will flow through the meter
C. An admissibly high current will flow through the meter and meter may burn out
D. the loading effect will be low

Answer : An admissibly high current will flow through the meter and meter may burn out
Explain:-

9. The insulation resistance of a cable can be measured by

A. Ammeter-Voltmeter method
B. Megger
C. Kelvin's double bridge
D. Wheatstone bridge

Answer : Megger
Explain:-

10. The meter constant of an energy meter is 1500rev/k Wh. The disc makes 3000 revolutions in a given time, the energy consumed is

A. 4 kWh
B. 1 kWh
C. 3 kWh
D. 2 kWh

Answer : 2 kWh
Explain:-