Ignoramus11549 fired this volley in
:

Lloyd, what is the subsystem in the EDM that generates those pulses?
Can it be sold to some hobbyists or for an alternative purpose?

I've never seen the schematic for a modern one. Back in the 70s, the
simple ones used variable-frequency (variable speed) AC mechanical motor-
generators, and half-wave rectified it to get the pulses. I _seriously_
doubt if that clunky method is used now, with inverter technology at hand.

Maybe Gunner could answer.

LLoyd