# Re: How to Calculate the PF Factor of a mcahine

Home Electrical Engineering Forum General Discussion How to Calculate the PF Factor of a mcahine Re: How to Calculate the PF Factor of a mcahine

#12142

David Knight said:

Hi all

Please can someone help me, i am trying to calc the PF factor of my heavyduty machines.

I know the voltage and the amps but how do i calc the PF factor??

David Knight said:

Hi all

Please can someone help me, i am trying to calc the PF factor of my heavyduty machines.

I know the voltage and the amps but how do i calc the PF factor??

Dear Davis ;

First, if you know the Voltage, the current of the machine, the kind of machine ” Sigle phase  or  3 phases “, and the power of the machine, you can do a simple calculation to have the value of Cos φ, where :

– For Single phase machine : P = V x I x Cos φ

– For 3 phases machine : P = 1.73 x U x I x Cosφ

Noting that :

– V : value of voltage betwwen phase & neutral

– U : value of voltage between 2 phases.

– I : the current of the machine

but, if you don't know the power of the machine, so you should either measure directly the value of Cos φ.

regards.