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Re: [Fwd: California Instruments AC Power Supplies in Stock]

Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx>

At 05:49 AM 10/13/2005, Tesla list wrote: 
Original poster: Steve Conner <steve@xxxxxxxxxxxx>

Hi Stork,

I believe these AC power supplies use a rectifier to
convert the line voltage to DC, then an inverter to
turn it back to AC at the frequency and voltage of
your choice. They should replace a variac no problem.
I think the variable frequency would be fun too, since
you can use 400Hz transformers, and change the
breakrate of a sync rotary gapped system. If you can
get one that generates three phase current off a
single phase input, even more fun :-)


And, I'll bet they're a bunch more expensive than a variable transformer. (any thing that has the word "calibrate" in the spec sheet....)


Just as a note, a lot of older 3phase inverter motor drives (using old bipolars and FETs) show up on the surplus market, and these are often independently programmable for frequency and voltage. Feeding them from single phase you'll get a sort of ripple, but you can also bump up the bus capacitor size to reduce it. A 5HP sized one of these is a box about 12"x18"x8" and a pretty hefty chunk of metal (One brand is Parametrics Parajust)

For comparison the newer IGBT ones are more like a 6" cube.

As with any clunky old hardware, though, you might have a challenge finding documentation, and if something in the box cooks, you'll have a tough time fixing it.