Testing an old 1940s/50s Zenith Variac 2000VA 8A model 100-R (?)
I get to test and learn about variacs with a chance encounter of a Zenith Variac from an attic find. These seem to have been made in/around 1940s-50s.
With a healthy respect for the power of mains voltage, I do basic cleaning and visual inspection, DC ohmic testing of the auto transformer, then start testing with 5VAC, then 120VAC and finally 250VAC, with modest loading through my dim bulb tester and finally with 1600W/6.6A@240V hairdryer.
Variacs are useful the needing to “bring up” the voltage of mains equipment that needs repair or testing.