[ARC5] Need Help with Variac Diagnosis

[Kenneth G. Gordon]

On 19 Feb 2015 at 20:17, Bruce Long via ARC5 wrote:

> The breaker tripping at no load might be in-rush current but if that is the case
> it should only trip the breaker - say- 1 out of three times.

Yes. Exactly. And that is what happened with mine: about 1/3 to 1/2 the time.

>  If you close the
> power switch at the peak of the 60 Hz sine wave peak, the in-rush current will
> be very small.  Large in-rush currents happen when you close the power switch
> near the sine wave zero crossing point when voltage is at a minimum --- no I did
> not get that wrong, power on at V=zero is the worst case.  

Yup. :-)

Ken W7EKB