Question

3. A dc A-h meter is rated for 15 A, 250 V. The meter constant is
14.4 A-s/rev. The meter constant at rated voltage may be expressed

(a) 3750 rev/kWh.
(c) 1000 rev/kWh.
(b) 3600 rev/kWh.
(d) 960 rev/kWh. ​

Answer 1

Given:

I = 15A

V = 250V

Meter constant = 14.4(A-sec/rev)

To find:

The meter constant at rated voltage may be expressed as

Solution:

Meter constant (A-sec/rev) is given by

14.4 = I / speed

14.4 = I / (K × Power)

Where 'K' is the meter constant in rev/kWh

14.4 = I / (K × V × I)

14.4 = 1 / (K × 250)

K = 1 / (14.4 × 250)

$K = \frac{1}{(\frac{250 * 14.4}{1000 * 3600} )}$

K = (1000 × 3600) / 3600

K = 1000 rev/kWh

Therefore, the meter constant at rated voltage may be expressed 1000 rev/kWh.