converting 440 to 220

A friend of mine just bought a older turett lathe that has a 5 hp 220 only two speed motor in it. His shop only has 440 three phase and 220 single phase wiring. What are his options, bearing in mind he is retired and and doesn't want to spend any more than needed to get this running?

Used 8 or 10 KVA three phase dry type general purpose transformer that says 460/230 or 480/240 on the tag

John

EMSCO 763-571-9005
good used transformers and everything else
http://www.emscomn.com/
they are just on the other side of the river from you
at that size might be just as cheap to look for a used motor
you could also put a vfd on it at that hp would be 500 bucks or so for 440 in and 220 out

You may want to be carefull trying a vfd. I have a lathe which has a 2 speed motor and runs on 220 volt
3 phase. It is 5 h.p. and 7 1.2 h.p. at the different speeds. I bought it used as the owner in the shop could not keep it running electrically. After drawing three different schematics, I finally figured out they were running it in a WYE or a DELTA configuration according to which speed was selected. I have been doing electrical work since I was a kid on 3 phase stuff but had never seen that before.

You could also look into having the motor re-wound for 480v, I just had that done to a mill I bought to go from 480v to 208v. The total re-wind was only about 300.00.

You could also look into having the motor re-wound for 480v, I just had that done to a mill I bought to go from 480v to 208v. The total re-wind was only about 300.00.

Click to expand...

If you find the right motor guy and you have the right motor, you might be lucky enough and have a quick fix (ie- only a couple hours of labor ~$100) since you're going up in voltage. By going up voltage, the motor guy will halve the number of grouped windings to keep the current constant in each. In other words, he'll take two individually windings or set of windings that are connected to the power leads and he'll tie them in series to form one set. This might be done by simply removing the bellcap and reconnecting the leadwires from the windings. If you're were going down in voltage, it might difficult to impossible to do this without a major rewire. Might want to suggest this to the guy doing the rewire if you go that route.

He'd definitely come out best by just getting a transformer to drop the voltage. Chances are there's more than one motor on the machine unless the coolant pump, etc is driven off a PTO from the headstock like some of the old W&S turret lathes. Some machines that were built for 220V only, use 250V rated electrical components. To convert a machine like this, he'd need to go to 600V components which would cost more than a transformer and entail lots more work too. At the minimum, he'd need to find heaters for both halves of a likely obsolete 2speed starter. Finding heaters like this can be difficult, and people who have them don't sell them cheap. The machine may currently use a 110V control circuit, and if so, he's have to add a txfmr to get that back to 110V even if he did go to 440V on the motor. A rewind on a 2 speed motor isn't a cheap proposition either, and most any lathe that came with a 2 speed motor needs both speeds to have an adequate range of spindle speeds. My WAG is that he'd spend more on a rewind alone than he paid for the lathe.

In comparison, with a transformer, you hook up the 3 incoming leads, make the ties for the proper output voltage, and hook the output to the lathe. He won't find anything else that's cheaper, simpler, or less work intensive.

wye?
delta?

sounds like a fork in the road in new orleans

trans is the least work
hands down