1. The braking torque of induction type single-phase energy meter is:
2. If an energy meter disc makes 10 revolutions in 100 sec when a load of 450 W is connected to it, the meter constant (in rev / kW-h) will be:
3. One single-phase energy meter operating on 230 V and 5 A for 5 hours makes 1940 revolutions. The Meter constant in revolution is 400. The power factor of the load will be:
4. Watt-hour meter can be produced using:
5. The meter constant of an energy meter will be given in:
6. The full-scale deflection in an induction instrument is about:
7. In a watt-hour meter, the creeping error is reduced by:
8. An energy meter is designed to have 100 revolutions of the disc per unit of energy consumed. The energy consumed by the load-carrying 50 A at 230 V and 0.8 power factor. Find the percentage error if the meter actually makes 950 revolutions.
- 3.26% , Slow
- 3.15%, Slow
- 3.26%, Fast
- 3.15%, Fast
9. The meter constant of a single-phase energy meter is 500 rev/kWh. The meter takes 86 seconds to make 50 revolutions while measuring a full load of 4.4 kW. The percentage error in the meter is
- – 2.43%
- – 4.86%
10. What does the reading of the first dial on the right of a 4-dial watt-hour meter indicate?
- Number of single units
- Total watts each hour
- Maximum value the meter can register
- Multiplier value of the preceding dial
11. Creep error may occur induction type energy meter due to
- Incorrect position of brake magnet
- Incorrect adjustment of position of shading band
- Overvoltage across voltage coil
- Increase in temperature
12. An energy meter with a constant of 600 revolutions per unit used for energy measurement. It makes 500 revolutions in 30 seconds. Find the energy consumed by the load for an hour.
13. Which energy meter system contains a rotating aluminum disc that is placed between the air gaps of series and shunt magnets and mounted on a shaft?
14. Which of the following is the cause of meter phase error in induction type energy meter?
- Incorrect position of brake magnets.
- Incorrect adjustment of the position of shading bands.
- Slow but continuous rotation of aluminium disc.
- Temperature variations.
15. The disadvantage of time measurement testing in energy meters is
- Accuracy variation due to test load
- Need continuous Monitoring
- Meter constant can’t be determined
- All of the above
16. A 230 V single-phase energy meter has a constant load current of 20 A at unity power factor. If the meter disc makes 2300 revolutions for 2 hours, the meter constant will be:
17. The kWh meter can be classified as a / an instrument:
18. A 230-V, 50-A energy meter on full load test makes 61 revolutions in 37 seconds. If the meter constant is 520 rev/kwh, what is the percentage error?
19. If an energy meter makes 5 revolutions in 100 seconds when a load of 225 W is connected, the meter constant is
- 800 rev/kWh
- 222 rev/kWh
- 147 rev/kWh
- 13 rev/kWh
20. If an energy meter disc makes 10 revolutions in 10 minutes when a load of 600 W is connected to it, the meter constant in rev / kWh is:
21. In short time test of energy meter the other meter used is
- Substandard type
- Standard type
- Either 1 and 2