Options for replacement lathe spindle motor

[Muzzer]

I'd have gone for a 2 pole 3-phase induction motor with a decent quality VFD. That will run at close to 3000rpm at base speed. Go for an oversized machine like 2-3kW or so, so you don't need to change pulleys etc.

I don't agree with this current trend for using servos on spindles. Servos are designed for position control and VFDs for speed control. You can use a VFD for closed loop position control but servos are not so suited to speed control. As for the size of the motors, you can get induction motors in the same package as servo motors. While they are slightly larger, it's not a massive difference but a larger "conventional" TEFC industrial motor is considerably cheaper.

[Doddy]

...though replacing the BLDC motor on the mill with a servo was precisely because it fitted the same highly restricted space envelope, for the same power, for less than the price of the replacement BLDC control board which I'd blown twice (okay, factor in the new pulley and belt and it was probably a bit more total cost), but it removed all the analogue uncertainty of spindle speed control or any third-party interfaces (that spindle, also step/dir control). Plus (and some might cringe at this) - the option of a spindle lock