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Today I was able to bench test my first 3-phase AC gearmotor running on VFD. It's a foot-mounted Sew-Eurodrive 1-horsepower with 4.5:1 gear ratio. Gearmotor A four-pole AC motor typically has a speed around 1500 rpm when fed 60Hz power from the wall. With the 4.5:1 gear reduction, that puts us around 330rpm with wall power (60Hz). So long as the AC motor is 3-phase, we can add a VFD in the mix to control the frequency of the power going to the motor. And voilà, we have a motor that can go anywhere from 0rpm up to 330rpm. At least that's the theory I've been reading for the past few weeks...I hadn't seen any of this in action until today. This ragamuffin came to me by way of ebay. Here is the original listing. I'll include a screenshot of the listing because these listings go away eventually. This motor is bigger than I needed. 400 watts (1/2 horsepower) or maybe even 100 Watts (1/8 horsepower) would suffice. But this one I found for a song, only $65 after shipping. I did verify that it was actually 3-Phase before buying. (See the "3PH" in the upper right corner of the motor nameplate) The box arrived a few days later. It was packed cozily in cardboard and foam. The outside of the motor is gritty. Perhaps it's been running in a moist environment. The ad says it was taken from a running system. I'd like to clean it up and paint it, but I want to see it run first.. The wiring was set up for 380V, so I reconfigured according to the diagram for the 220V that my VFD will output. (My VFD takes 110V single phase as input, and outputs 3-phase in the range of 220V.) Here is before and after, note the copper strips have been repositioned under the nuts to effect the wiring change. VFD The VFD (variable frequency drive) I've actually had for a couple weeks while I've been looking for motors. But I've never owned any 3-phase equipment so had no way to really test the VFD, hence the excitement when the gritty box finally arrived. 🤪 Here is a link to the VFD I'm using: https://www.amazon.com/dp/B0D53Z7RZ5 And a screenshot: Here's what the back of the VFD looks like. The two red "AC" labels are for neutral and 110V single phase input. FG is ground, connecting both to ground in the wall outlet and to the ground on the motor. The blue U, V, W are the 3-phase outputs which the VFD can control to be any frequency from 0Hz up to I think 100Hz, which is how the VFD accomplishes speed control on an AC motor which would otherwise be fixed speed. The green strip on the right is for low voltage input/output. One of them can be used with an external potentiometer to set the frequency. I've ordered a TIG pedal for this but it has not arrived yet---So today we'll use the built-in potentiometer/knob on the front of the VFD to control our speed. Bench Test Here we are on the bench: And a video gearmotor-voice-01.mp4 Many thanks to @GerryR who has fielded a LOT of questions from me as I've been pursuing this journey.