RVUNL EE Electrical & Electronic Measurements Quiz 2

Consider a wattmeter that is rated at 20 A, 50 V is having the following characteristics:

If the potential coil is connected across the load and is purely resistive. Then at rated condition, error in reading is

When measuring power in a circuit with low current, the wattmeter current coil should be connected

In 2-wattmeter method for measurement of power in a star-connected 3 phase load, magnitude of the two wattmeter readings will be equal

A 400V, 60Hz energy meter has a meter constant of 50rev/kWhr. When it is supplying a load of 10A at 400V and 0.8 power factor it makes 55 revolutions in 21 minutes. The percentage error in the instrument is

An energy meter having a meter constant of 1000 revolution per KWh is found to make 10 revolution in 90 sec. The load power is