I've got a true 3ph 100A service and a 240v Cold Saw (for cutting steel). Can I rewire this saw for use in my 208v service? Obviously if I just grab 2 hots and the N I'll only get 208 across the poles and 120 at each leg, so I would assume that I would lose efficiency at the very least. But can it be done correctly without installing a transformer?

Jwd.

208 is a bit low to run a true 240 volt motor. It may run to your satisfaction sine a cold saw is not a large load on the motor. Motors run best when the voltage is within 10%.

I am assuming the motor is single phase, which would need the two hots of the 3 phase system, but the neutral will not be needed.

Let me know the horsepower of the motor, I can recommend the size of a Buck Boost transformer. One small B-B transformer will be less costly than sending the motor out to be re-wound for 208 volts.

Actually TK I was incorrect. The saw belongs to a buddy of mine who bought it off a carpentry/metal shop and told me it was 240, upon inspection. The motor is actually a 230v 3ph. So I should be good to plug it on in, no?

Jwd

A 230 volt motor will meet the 10% tolerance by one volt. 230V motors work fine on 208. If the voltage goes much lower than 208 ,there may be performance issues, but again, as a cut saw there is very small load, and it should work fine.