"Koz" wrote in message
...
|
| Just curoius...one of these days I have to switch an inductive load on a
| forging machine somehow. Output is about 6000 amps at 3 volts. Makes
| the theoretical (no loss) input about 75 amps at 240 V. The problem is
| that things are so highly inductive, any digital switching would have to
| be far greater than the 75 amp rating. That gets spendy. If you could
| gang the darned things, the cost would be MUCH better.
|
| Any ideas on a cheap but digitally controlled solution? In the old
| days, one might use mercury relays. Regular relays will fry and lock.
| Of course there are ways to suck up the initial inductive load but I'd
| rather keep things simple.
|
|
| Koz

I've seen "hockey puck" IGBT's and SCR's in the several thousand amp
range. Haven't seen much on ebay but there are on the surplus market.
Several hundred bucks a pop, compared to several thousand bucks a pop new.
IIRC, the voltage range was in the thousands, though, and wouldn't know what
the forward drop would be.
There are lighter duty devices ranging from minimal amperage to several
hundred. Look for IGBT and SCR's on ebay. To switch AC fully with SCR's
you need two back to back, which is essentially what a TRIAC is.