Do not swap the motor for a single phase, use an RPC, VFD or similar. Is your motor 5HP ? Some machines take quite a bit more on startup, but I don't think a mill is typically one of them, a lathe yes, but typically not a mill.Homemade wrote:Would a 5 hp phase converter be cheaper then a single phase spindle motor and solve the 3phase coolant pump issue.
Normally you would want a 7-1/2HP RPC to power a 5HP machine, that is the general rule of thumb. But on a mill you might be able to start 5HP with a 5HP RPC, that I don't know.
Also, wire for the circuit, not the machine. IOW, wire for the max possible draw on the circuit rather than the max amps of the machine which can often be less. Using a 30 amp plug with 20 amp wire is not a good idea, as an example.
You can save some money by buying a complete RPC box, and hook your own idler motor up to it.
I use an Anderson 7-1/2HP RPC in my shop and have several 5HP machines as well as smaller machines I run off it. All are wired for the circuit.
HTH,
Alan