Re: VFD for EDM

>
> VFDs do not produce a sine wave. They produce variable pulse width
> 400 V pulses at something like 15 - 25 KHz rate.

one problem is getting the DC bus down to under 100 volts for a
smaller spark gap. the spark gap increases about 0.001" for every 70
volts or so. that means you would be cutting a larger mass than
needed.

> I would strongly advise against trying it. The chance that the VFD

will

> be destroyed is close to 100%. The EDM may also be damaged.

I like the idea that a 3 channel pulse could spark each channel
independently, but then protecting the other 2 will be difficult.

I see the dropping of the DC bus, the additon of protection circuitry
and the brain trasnplant to be more work than building a simple unit.

> I hate rotary converters,
> but in this case,
> I think that is your only choice.

I see an R/C as simple, espically if one is only after 1 amp. what
would the benefit of a rotary offer above that ?

Dave