Size And Type Of 3 Phase Transformer?

Could you elaborate on that John? I don't see a neutral on the drawing he posted. Also couldn't he use a delta or wye type transformer, depending on what's available? Wye types do have neutrals.
MS
 
markba633csi said:
Could you elaborate on that John? I don't see a neutral on the drawing he posted. Also couldn't he use a delta or wye type transformer, depending on what's available? Wye types do have neutrals.
MS
Click to expand...
I should have written "grounded conductor", not "neutral". One of the wires coming out of the RPC is the grounded white wire of the single-phase supply. This doen't matter with an isolation transformer: the secondary is a seperately derived system and the grounded conductor will be whatever you make it. With an autotransformer, however, that grounded conductor connects to a tap so that all three of the autotransformer output terminals will be hot with respect to ground (but not symmetrically as they would be in a three-phase system with a grounded neutral). It'll work fine for motors, though.
 
Got it- I don't know how common 3-phase step-up auto formers are, I suspect the OP will end up with an isolation tranny so the neutral/hot tap stuff won't matter. Ropata: post a pic and/or specs of the transformer you are considering and we will advise you. Happy shopping...
Mark S.
 
markba633csi said:
Got it- I don't know how common 3-phase step-up auto formers are, I suspect the OP will end up with an isolation tranny so the neutral/hot tap stuff won't matter. Ropata: post a pic and/or specs of the transformer you are considering and we will advise you. Happy shopping...
Mark S.
Click to expand...
You *can* use three single phase transformers.
 
I would love to post a picture of one I'm looking to buy but damned If I can find anything even remotely close to what I need.
 
It will be heavy that is for sure. 50 or 60 Hz would work OK. Also like John said you could use three single phase and wire 'em up in a triplet. Look at Temco TT 1772 it is only 55 pounds but expensive at 2,000 $. You might check ebay for something like that...
MS
 
Might be a little small for your purpose. 0.4 KVA vs the 7.5 KVA that you need for 10 HP
 
You must log in or register to reply here.
Back
Top