MotionRebuild shelfUnplug and unscrew
AC synchronous gearmotor
Also called turntable motor, microwave motor, clock motor.
A mains-frequency motor with a gearbox already attached. Microwave turntables are the classic: a few RPM, surprising torque, runs all day.
If you are new to this category
These parts spin, push, or pump. A motor is a machine that turns electricity into turning. Some start turning as soon as you connect a battery. Others look identical and will not move until a small circuit tells them which coil to power next. The label, or the number of wires, is how you tell them apart.
Count the thick wires before you apply power. Two wires usually mean a brushed motor that can run from a battery. Three thick wires usually mean a brushless motor. Keep the board that came with a brushless motor.
Two wires mean you can try a low, current-limited voltage and it should spin. The case often hides a label. If the only label you can find is on the machine, that voltage is the one to believe, not a hobby guess.
Mains voltage. Line voltage, and the DC bus just after the rectifier, both kill. A disconnected cord is not a discharged supply.
| What to look for | Usual figure |
|---|---|
| Supply | 120 V or 230 V AC, as printed. Not DC. |
| Speed | Often 2.5–6 RPM at the output shaft of a microwave motor |
| Direction | Many reverse if you stall them briefly; some have a direction lever |
Volts are electrical pressure, amps are how much current is flowing, and ohms are how hard the part resists that flow. A higher voltage than the part was built for is how salvage parts die on the bench. If a cell in the table says “read the stamp”, that stamp is the whole specification.
What people actually use it for
- Displays
- Slow rotisseries
- Time bases tied to line frequency
- Stirring
Leave this one when
You needed variable speed. This motor is locked to the mains frequency.
Buying a new one is the better idea when
A DC gearmotor, if you need speed control rather than a fixed crawl.
How to tell if this one still works
Read the plate. Brief mains run with the shaft free. Do not hold the shaft stalled for long; the coil is small.
Tools you will want: Meter.
Words on this page
Short meanings, so the rest of the entry is readable if you are not already doing this every weekend.
- mains
- Ordinary household wall power. It can kill. Unplug before you open anything that used it, and do not experiment on live wiring.
- torque
- Twisting strength, as opposed to speed. A gearbox trades speed for torque. That is why a drill can turn a screw slowly with force.
- RPM
- Revolutions per minute. How fast the shaft turns. A microwave turntable motor is a few RPM. A blender motor is many thousands.
- stall
- The shaft is powered but not turning, because the load is too heavy. Current jumps. Plastic gears strip. Fuses exist for this moment.
Where people actually find it
1 notes, most useful first. “Leave it” means the part is in that machine and you should not take it: it is dangerous, worn out, or only useful if you already know that exact repair.
| From | Call | How many | How often | Where it sits |
|---|---|---|---|---|
| Microwave oven | Prize | 1 | always | Under the turntable. |
- In this particular machine
- Mains synchronous gearmotor, a few RPM, marked 120 or 230 V.
- Where to look
- Under the turntable.
- How to get it out
- Two screws, a connector. This is the one to take.
- The condition to expect
- Usually perfect.