Errors Associated with Energy Meter

Q. The meter constant of a 230 V, 10 A watt-hour meter is 1800 revolutions per kWh. The meter is tested at half load and rated voltage and unity power factor. The meter is found to make 80 revolutions in 138 seconds. The meter error at half load is ______ % fast.

1. 0.817

Q. An energy meter rated as 5A, 230 V makes 600 revolutions per kWh. If in a test at full load upf, it makes 6 revolutions in 30 seconds. Which of these given statement(s) is/are not correct?

1. Meter runs faster than its nominal speed.
2. The error associated with particular meter is 4.16%
3. Meter akes 720 revolutions in one hour during test.
4. Meter can be corrected by placing a braking magnet closer to the center of the disc to slow down its speed.

Q. The brake magnet of an error free electromechanical, induction type energy meter is shifted from its position and moved a small distance towards the edge of the disc. Then the meter will

1. continue to work correctly without any change in its characteristics
2. continue to work, but registers a lower kWhr
3. continue to work, but registers a higher kWhr
4. stop working