Denford Software & Machines

Can anybody tell me the RPM of the 3 phase motor on the Viceroy 250 TDS/3/C/M/L.

I want to convert to a single phase motor but cannot do so until I find out the RPM required.

I've looked all over the lathe and motor - no sign of any plate giving the info.

I changed the 3-phase motor to a single phase motor on my 280 and it was the worst thing I ever did. The 3-phase motor is far smoother and the single phase makes the splash guard and cabinet doors buzz. I would give very serious consideration to fitting a VFD and keeping the original motor, because by the time you've bought a motor and new contactors you will have spent the cost of a VFD anyway and the VFD will give you variable speed, braking and instant-reverse.

Anyway, to answer your question:

The 3-phase motor on my lathe was 1425rpm. If you are going for the most common type of single-phase induction motor you'll either get a 2-pole or a 4-pole one. 4-pole is what you want as it will give you 1425rpm at it's rated load and has double the torque (along with half the RPM) of a 2-pole.

https://www.engineeringtoolbox.com/speed ... d_738.html

Many thanks for the information, I'll certainly look into a VFD.
I almost bought a motor today but the shaft diameter was too big so you saved me from a possible (costly) error.