Guys,
Need to power an induction heater. Unit requires 40 amps of 480 volt, 3 phase.
I have 200 amps of 240 volt 3 phase available.
I guess I need to know the KVA rating of the step up transformer.
Thanks in advance.
Chuck
Burbank, CA
Heating is easy compared to starting motors as loads, so what that ex-jarhead just said. The basic math JF works. For a change..
Then availability and shipping costs weigh-in.
Too small overheats. Too large is an initialization PITA and wasteful if/as/when idling. You will want disconnects on the INPUT side, IOW.
Your search-for-a-bargain range should be about 20 KVA 'dry type"...fortunately a common rating, indoors., outdoors, NEMA dual use housing.
Copper-wound is better, but any MAJOR maker knows how to do shiney-wood properly, too. They have scant choice, given the costs.
Transformers actually DO have "moving parts" consequently CAN "wear out".
Not only do the laminations move, the wire in the windings is actually squeezed to a tiny, tiny amount of smaller diameter and ever-so-slightly longer length, then reversed, with every cycle over scads and scads of cycles.
Designers expect that, goal for 20-plus years of fatigue-endurance of continuous cycling with rounded-corner or "semi-square" coils, twice that with R.E. Uptegraff's "elliptical" wound bobbins. There are white-papers on all that s**t.
But the bottom line is that most "dry type" used transformers that look OK probably ARE OK as far as low-risk purchases. Few ever ACTUALLY get "worn out" OR "burnt up" and survive into for-sale inventory of any "regular dealer". Smoke trails, polymer stencch, burnt places at terminals, etc? Off they go to recover the metal. Recyclers don't want hassle any more than new OEM want it.
Most used goods are in the market because of business needs changes, alterations, and upgrades. SOME were of low-efficiency designs, but not by MUCH.
Others were surplused off the back of commercial business operating / economic failure, not electrical failure.
If in doubt, check new prices first, THEN scout to see if you can gain for the modestly greater risk.
2CW