# Re: Multiple Factor

#12185
Spir Georges GHALI
Participant

Hello Engineer,s

please tell me that how to get a multiple factor in power transformer, in energy meter,s , and in current transformer.

thank,s and regard,s.

Dear Mr. Ikram ;

Energy Meter : the maximum used Energy meters in low voltage networks have the following specifications :

– 3 Phases + Neutral / 400/231V ( accordingly to the phases votage in the country )

– 5 Amp ( 6 points composed 3 inptuts )

that means that the maximum value of circulated current in the energy meter is ” 5 A “, so, when we have a current bigger than 5A we should use a current transformer, that can be installed to the input of current.  For exp. if we installed 3 CT that aew ” 1000/5 “, we should multiply the measured value by the ration of CT's that means : 1000/5 = 200 ” so, each real comsuption is ” the measured value x 200 “.

Rem. : is we use the Energy Meter for Medieum Voltage, that means the voltage for it, in most of case, is ” 100V “, so, we should use ” Voltage Transformer ” where the ration is ” MV value / 100 ” and then we should multiply the measured value this ration and by the ration of CT

Current Transformers : we do the choice of the CT accordingly the the load's current and the value of the measuring apparatus. For exp. if the loads' current is 725A  and the input value of Ampmeter is 5A, we should use as CT ” 800/5   or  1000/5 ” and as Ampmeter ” 800/5  or  1000/5 “.

Regards.