[ARC5] BIG Variacs and popping breakers.

[Brian]

Far easier to add a series capacitor. I use oil-filled paper caps, not 
electrolytic, because they're polarised. I select for low leakage current to 
avoid heating problems.
I have built up a switched-capacitor box for finding the correct capacitor 
for each application. Works best when the load is relatively constant, eg, 
incandescent lamps, cooling fans, valve heater transformers. Also provides a 
form of soft-start, and there’s no magnetising VA loss.
73 de Brian, VK2GCE.

On Sunday, December 11, 2016 11:08 AM , Scott said:

I seem to have more trouble with the cheap Chinese variacs popping breakers.
Anecdotally, I have a very "stiff" AC system in my shop/shock (100 A
subpanel fed from my 400A main panel)  I use 10AWG wire on  my 20A 115V
circuits, and have spec, grade outlets.  I trip variacs more often at home
than my neighbor who has a very long run to his shack that is barely
adequate for his load.  I would suspect that the droop ion his line quells
many of those  nuisance trips.  (Not necessarily a good thing).

Scott V. Johnson W7SVJ