Can a garage door motor be connected directly to AC?

I have a garage door motor than I would like to use to make a ball mill but I'm unsure if it will even work. Will it run if I connect the red and blue wires to an AC current or do motors ONLY work DC? The white wire is ground right?

Also, if the motor originally used a "motor starting capacitor" will it still work without one since it doesn't need to lift a heavy load anymore?

Picture of Can a garage door motor be connected directly to AC?
Like the other guys said this is guessing game w/o all the info from the motor nameplate. We think this motor looks like an AC inducton motor, with a hint of a capacitor and the 3 wires - likely a "PSC" capacitor motor design. PSC motors require a "run capacitor" between two of the leads at all times. The grounding for this motor is likely done through the framework of the GD-opener. Green wire color (or green-yellow) is the universal ground wire color (globally).

If you want to get real technical, you might check the resistance between the leads. If the motor has two windings joined at one end (common) then one resistance reading should be the sum of the other two. Try a few microfarads (250VAC rated) connected across those two leads (i.e., the sum). If the motor is 3 wire reversible (AC) then the two windings should be equal in resistance. Connect one side of the line to common, the other side to either end of the capacitor. If my guess is right the motor will change direction as the line is changed from one side of the cap to the other. Increasing or decreasing the capacitance will result in more or less starting torque along with more or less motor heating. The capacitance for the run capacitor should be listed on the motor's nameplates.

Good luck! Ed (we don't make garage door motors; we make industrial type motors and gearmotors and drives)...
lemonie6 years ago
Run it as it was originally powered in the garage, or use something else (ball-mills don't necessarily need a big motor)

If it used a starter cap, its an AC motor, Not knowing how it WAS wired, I can't say, much else. It NEEDS the starting capacitor.
rickharris6 years ago
Hard to answer you question without hands on the motor BUT I would expect the motor to be DC as it will have been reversed to open/shut the door and run from a relatively low voltage DC supply perhaps 30 volts or so.

Looking up the maufacturer may help.