[ARC5] Transformer Hum

[Tim]

Hi - was it a 400 Hz transformer?  Maybe not enough iron for 60 Hz....?

On Tue, Mar 10, 2015 at 7:06 PM, Robert Eleazer <releazer at earthlink.net>
wrote:

> I had a transformer for some lights fail at home so I started going though
> a pile of unknown transformers to see if one would do the job.  A nice big
> hefty one had two black wires and three red wires; two of the red wires had
> stripes. I decided that the back wires, with a DC resistance of about 45
> ohms, were the primary and the red ones a center tapped secondary.
>
> I hooked up my Variac and found that the secondary voltage came right on
> up, topping out at 194V with 120V on the primary - but just before it maxed
> out, the transformer started humming.
>
> Would y'all take the humming as an indication the transformer voltage is
> too high?  In any case I was looking for one with a 12VAC output, so it
> won't do anyway.
>
> Thanks,
>
> Wayne
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