Re: [CAD_CAM_EDM_DRO] Re: VFD for series 1 bridgeport

Bill Vance wrote:

> On Sun Dec 23 21:14:00 2001, Raymond Heckert, <jnr@...> wrote:
>
> >Does anybody have any plans to make a high-power 3-phase inverter? I'm
> >thinking about charging a couple of BIG juicy capacitors through a
> >full-wave bridge, and use a sinewave synthesizer (3 of them timed 16666
> >microseconda apart) to feed a husky set of TRIAC's. I want about 15KVA at
> >230 VAC 3-phase. Any help would be appreciated.

Triacs? How do you turn them off if the supply is DC? You would want
to use IGBTs. You should buy a used or surplus 20 Hp VFD on eBay.
Playing with 400 V DC buses with 20,000 uF of capacitors is not for the
beginner! I have built several inverters, and they were a bear. I had
pieces of glowing power transistors shoot past my head, once in 'stereo'!
I ended up 'firing' up that project from UNDER the bench, with ear protectors
on!

Umm, why do you nead 15 KVA for a series-I Bridgeport? The largest
motors were 3 Hp.

Jon