Have you looked at other motor options like getting away from that DC brushed motor and into a suitable AC option?
Asynchronous Servo Spindle Motors that are specifically suited for VMC's and milling machines will offer you the best performance for your dollar and they are available in small packages.
Motor Specs: (real) Asynchronous Servo Spindle Motor
- 1.12KW (1.5HP) Constant Velocity / 1.5KW (2HP) Constant Torque.
- RPM: 12,000.
- Duty: S1@8,000RPM, S6@12,000RPM.
- Cooling: External 220VAC Electric Fan.
- Shaft DIA: 22mm with 6mm keyway (standard).
- Encoder: Optical 2500PPR
- Weight: 18lbs
- Supports Rigid Taping.
- Supports Orientation
I've been running mine with a VFD sample I was trying to produce that didn't fund on KS, it has 4 programmable orient positions and I've had no issues doing anything with this motor, RPMs from 100 to 12,000 are stable due to closed-loop tracking, in servo mode positioning is accurate within 3ppr and in orient it's also less than 3ppr (3ppr is the default position error margin, can be changed) of the target position.
At $1K for the combo it's the best bang for the buck, all things considered.
Forget Yaskawa VFD's if your on a budget, even a new Delta VFD-VE (3PH input, single phase never produced) with PG card that will run on single phase 220V (derated) with sufficient power (5.5KW needed for 1.5KW-2.2KW motor) will run you over $800.00 plus shipping, used is less and sometimes old-stock can be found in small quantities but sourcing the motor is where you run into difficulties as it's not likely you have a local source for a special application motor and it's not something you see advertised in your local hardware store.
Before you get any ideas of messaging me here to inquire about the motor and VFD combo, if you do message me here, don't expect a reply, I don't frequent here often and it may be 3-4 months before I return again and the message will have evaporated before this time.