MULTIPLYING FACTOR

WHAT IS MULTIPLYING FACTOR AND ITS FORMULA? 

MULTIPLYING FACTOR: Multiplying factor of meter is that parameters by virtue of which we use small scaled meter to get the reading up to multiplication factor times.

Now we will see the multiplying factor formula of different electrical meter:

1.FOR ENERGY METER: The given below formula used for finding the multiplying factor of energy meter.

M.F. = Connected CTR*Connected PTR  *1000

            Meter CTR*Meter PTR

The given term in formula is explained below.

a) Connected CTR: The ratio of Current transformer (CT) that is connected to panel (circuit breaker).

Panel CT ratio

b) Connected PTR: The ratio of connected potential transformer or voltage transformer (PTR) that is connected to the panel (circuit breaker).

Panel PT ratio

c) Meter CTR: The CT ratio of connected meter.

Meter CT ratio

d) Meter PTR: The PT ratio of connected meter.

Meter PT ratio

By using above formula and data we can find the value of multiplying factor of energy meter.

For example in give images:

Connected CTR= 200/5

Connected PTR= 11 kV/110 V

Meter CTR= 200/5

Meter PTR= 11 kV/110 V

So multiplying factor of this energy meter is:

M.F. = 200/5*11 kV/110 V *1000

            200/5*11 kV/110 V

        = 1000

Multiplying factor of the above energy meter is 1000.

Now we can use above formula for any value of  panel CTR & PTR and meter CTR & PTR to get the multiplying factor of energy meter.

2.AMMETER MULTIPLYING FACTOR: The ratio of circuit current (current to be measured) to the current taken by meter is known as "multiplying factor" of ammeter.

I = the current to be measured (I>Im)

Im = the current through meter.

M.F. = I/Im

3.VOLTMETER MULTIPLYING FACTOR: The ratio of voltage to be measured (circuit voltage) and the voltage across the meter is known as "multiplying factor" of voltmeter.

V = the voltage measured (V>v)

v = the voltage drop across the meter.

M.F. = V/v

4.WATTMETER MULTIPLYING FACTOR: The same formula of energy meter multiplying factor is used for find the multiplying factor of wattmeter.