=A0 =A0I'm interested in measuring amperage in three phase equipment
> with three Jaycar current sensing clamps that can output 10mV/Amp.
>
> =A0 =A0I have to feed a DC input data logger so I built an opamp based
> peak detector which outputs a smooth DC voltage that matches the
> peak AC output of the current clamp.
>
> =A0 =A0My query is this: how do I find the total three phase KVA if
> I have the peak current in each phase?.
>
> Assuming a balanced load would it be: KVA =3D sqrt3 x 415V x Amps?.
>
> Thanks
> Mark
Yo,
If you have a value for peak current (as opposed to RMS) divide it by sqrt2 to give you the RMS current for each phase. You need the RMS value to get a kVA figure. The above formula you mentioned only applies for balanced three phase systems, which depending on the application may or may not be the case. Seeing as you are measuring all three phases:
kVA =3D (red phase amps * 240) + (white phase amps * 240) + (blue phase amps * 240).
This obviously assumes the voltage is 240, multiply by the measured value if you have that.
Out of curiosity why do you need to do this ? There are a crap load of commerically available pieces equipment which do this and much much more..... Amazing how cheap some of it is too considering what is does
Cheers