Wow/flutter issues P3-24 — measure motor accuracy?

I've had this issue with the table as long as I've owned it. I've replaced belts, re-lubed the bearing and have had no success. I'm wondering if it's the motor.

Is there a way to check that the motor is spinning at a consistent speed? Like, I'm just going out on a limb, take off the belt and use a multimeter to measure ______ to see if it's consistent?

Thanks