# What do the numbers on motors mean (How do I read them?)

I salvaged from an old microwave, the motor that spins the food tray. I'm trying to figure out how much voltage I need to apply to it in order to get it to spin, but I cant make any sense out of the numbers on it. It's a Synchronous Motor.

This is what's on it:

100/120v~ 50/60Hz 4W 4/4.8r/min CW/CCW

I can guess that it rotates from 4 to 4.8 rotations per minute? but other than that, I'm clueless. What do these other things mean? Thanks so much!

Taking a few guesses here, but:

100-120V~: operating voltage, "~" (tilde) indicates AC voltage

50-60Hz: operating AC frequency

4W: power consumption (maximum stall perhaps?)

CW/CCW: works in both ways (clockwise and counterclockwise.) This usually means it is a synchronous motor, and its direction depends on either the sign of the incoming AC waveform, or whichever direction has the least torque - in other words, it's more or less random.

• It's synchronous to the power frequency. So 4 revs per minute at 50 Hz power and 4.8 at 60 Hz. – markrages Nov 20 '10 at 0:46
• 100-120 is what you will get out of a wall outlet in the USA. 60Hz is what you will get in the USA also. – Kortuk Nov 20 '10 at 1:22
• Does this mean that I will need 100-120 volts in order to get it to spin? – Walt Nov 20 '10 at 2:41
• @Walt - Yes. Also, it HAS to be AC. – Connor Wolf Nov 20 '10 at 6:13
• @Walt - High voltage does not mean lots of juice, it just means high voltage. Power (or juice, if you will), is voltage * current. – Connor Wolf Nov 21 '10 at 4:09

CW/CCW - Clockwise & Counterclockwise. a lot of turntable motors for microwaves will alternate the spin direction to help even out cooking, each time it is powered up the spin will reverse from the previous time...

1st time, let say clockwise 2nd time, then counterclockwise 3rd time, clockwise again...