I'll take a stab at this: I see three round things and rotating things below that It's some variation on this variable autotransformer: https://en.wikipedia.o

I'll take a stab at this: I see three round things and rotating things below that It's some variation on this variable autotransformer: https://en.wikipedia.org/wiki/Autotransformer#Variable_autotransformers https://en.wikipedia.org/wiki/Autotransformer#Variable_autot... that's a way to gradually increase voltage. isn't it dangerous I was also more than vaguely disturbed by how casually he was operating. That bulb perched on a stool didn't seem all that stable. But as you say, "he probably knows what he's doing". how do you get that amount of power in a house? "two hundred amp service" is very common in the USA. I just checked the breakers in my garage. My main breaker is labelled 200 Amps. It has two "poles". Which means there are two separate 120 Volt inputs (referenced to Neutral). The inputs are 180 degrees out of phase, so across them is 240 Volts. 240 * 200 = 48,000 watts.