A 230 V, single-phase domestic energy meter is connected to a con
| A 230 V, single-phase domestic energy meter is connected to a constant resistive lamp load 4 A. It makes 2300 revolution in 5 hours. What is meter constant in rev/unit?
A. 500
B. 250
C. 450
D. 300
Please scroll down to see the correct answer and solution guide.
Right Answer is: A
SOLUTION
Concept:
In a energy meter,
Meter constant = (Number of revolutions) / (Energy consumed (E) in kWh)
E (in kWh) = voltage x current x cos ϕ × time x 10-3
Calculation:
Given that,
Voltage = 230 V
Current = 4 A
2300 revolutions in 5 hours
Number of revolutions in one hour = \(\frac{2300}{5}=460\)
Now energy (E) consumed by the resistive load in one hour is
E = 230 x 4 x 1 x 10-3 = 0.920 kWh
Hence meter constant of domestic energy meter is
Meter constant = (460) / (0.92)