Page 865 - Basic Electrical Engineering

Therefore, T α θ.
c
For steady deflection, T = T .
c
d
2
Thus, T α I and T α θ
d
c
Equating, θ α I 2
Now θ α
1
and θ α
2

So

or,

Substituting values

Example 11.9 The meter constant of a single-phase energy meter is 1200.

When a load of 6 kW is switched on, the disc of the meter made 136
revolutions in 1 minute. Calculate the percentage error.

Solution:

Actual energy consumed = 6 kW × 1 minute = kWh = 0.1 kWh. Meter

constant is 1200. This means for 1 kWh of energy consumed, the disc of the
meter makes 1200 revolutions.