breaker sizing, 220V 1 Ph
breaker sizing, 220V 1 Ph
(OP)
I just got a lathe and a mill. The lathe uses 220 V 3 Ph, and the mill uses 480 3 Ph. All I have is 220 1 Ph coming into the building so I know I must buy inverters to make each machine run. However, the lathe motor has 7.6 FLA and the mill motor has 1.65 FLA. When the 220 1 Ph breaker panel goes in, how do you calculate the breaker size since it will be at 220V 1 Ph? I guess the minimum breaker size is 15A, but does the amperage change between 1 Ph and 3 Ph?





RE: breaker sizing, 220V 1 Ph
Have you investigated the mill to see if you can re-connect it at 230V instead of 460V? Almost all would provide for this. You are not likely going to find any 240V 1ph to 480V 3ph inverters so you want to look closely at reconnectability.
There are many ways to approach your solutions. Are both of these tools only motor driven or do they have other electrical aspects like controllers and such?
Keith Cress
kcress - http://www.flaminsystems.com
RE: breaker sizing, 220V 1 Ph
RE: breaker sizing, 220V 1 Ph
I think you have inverter and converter meanings confused. You state, that the mill has a inverter. To me that means a VSD (variable speed drive) and a converter changes single phase to three phase. The VSD most likely only works at 480 volts 3 phase. Check to see if the lathe motor can be changed to 480 volts. If it is a 2 speed motor, as most lathes are. you are suck with 230v. You might need 2 converters, one for 480v 3ph and 240v 3ph.
good luck,
Dave
RE: breaker sizing, 220V 1 Ph
I have a converter for the mill, it has a round motor-like device with it. Not a VSD (VFD).
The lathe has a 2 speed wired for 220 (230? 210? 240?) at 1800 rpm. It does not use a VSD (VFD), it changes speed by gearbox sequencing, not belt drives. I would not want to change it to 480 if I could help it, since I don't know how.
RE: breaker sizing, 220V 1 Ph
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: breaker sizing, 220V 1 Ph
good luck,
Dave