Re: HOW TO MEASURE XFRMR POWER?
Subject: Re: HOW TO MEASURE XFRMR POWER?
From: "Malcolm Watts" <MALCOLM-at-directorate.wnp.ac.nz>
Date: Tue, 27 Feb 1996 08:31:28 +1200
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A suggestion on this....
> I have 2 12KV transformers. They are about 2.5' cubed and filled with oil.
> have been able to tell the output voltage by placing 10VAC on the input and
> measured 1200VAC on the output. The tricky part is how to tell what the powe
> rating is. There is no indication of who made them or any stickers or plates
> them of any kind.
> Does anyone have any ideas on a semi-easy way to tell what the maximum safe
> power output of the transformers are?
Connect a capacitor across the secondary of one of them, connect a LOW
impedance signal generator across the primary, then use a scope
connected across the capacitor and secondary to find the resonant
frequency. If you don't have an oscilloscope, you find resonance
easily enough by connecting a neon bulb across the
Knowing the value of C and f, calculate Xc by
Xc = 1/(2xPIxfxC)
This value will be = to Xl of your transformer. Since you know
that V = 12kV, you can calculate I = V/Xc which you can then
calculate a ballpark W = VxI from. You can also calculate W = V^2/Xc.
I think this should get you pretty close.