A 220 V single-phase meter has a constant load current of 5.0 A passing through it for 2 hours, at unity power factor.
A 220 V single-phase meter has a constant load current of 5.0 A passing through it for 2 hours, at unity power factor. If the meter disc makes 1056 revolutions during this period. What is the meter constant in revolutions/kWh?
Right Answer is:
480
SOLUTION
Energy consumed in two hours = V.I.cosφ.t
Where
Voltage V = 220 V
Current I = 5 A
Power factor cosφ = 1
Time (t) = 2 hours
Number of revolution = 1056
Energy consumed = 220 × 5 × 1 × 2 = 2.2 kWh
Meter constant K = Number of revolution/Kwh (rev/kWh)
K = 1056/2.2 = 480 rev/kWh