Hello!

I have a motor that has a sticker behind it says

DC12V
MMA-6P2RAP
Japan
28May91NB

It has 4 pads on it on a small pcb. Two of them are - and +.
Others has no identifier.
When I give voltage to + and - leads, the motor turns, and I can control it by pwm.
I measure the voltage on the other terminals and they give 2 V with 5% pwm and 0.707 V with 100% pwm(5V). But the voltage is not stable, and has big hops.
And unfortunately I don't have an oscilloscope.
Any idea?

 

The DC12V gives the operating voltage. Those leads with the erratic (to a meter) output might be for a tachometer function. You would need an oscilloscope to see the output properly.

 

my voltmeter's frequency reading give nothing

 

A search on the numbers MMA-6P2RAP turns up only this thread. You can always use it as a 12 volt motor and ignore the mystery terminals.

 

bump

Well, can it be the field or something like that? If it is, how can I make use of them?

 

It could be a stepper motor. Try the manufacturers of stepper motors.

 

picture dude...........what else is a better way.

 

OK, here are some pictures.. The wires were not originally there, I soldered them.
http://i42.tinypic.com/rhtv6q.jpg
http://i41.tinypic.com/1ywbqw.jpg
http://i41.tinypic.com/200633k.jpg
http://i40.tinypic.com/14e1g95.jpg

 

Hey. I have seen that in old tape decks. if so this ain't a stepper
where did salvaged it.

 

Could've been in a reel-to-reel tape deck or a phonograph (record player).

The logo on it looks like Mitsubishi's.

 

My friend bought it to me and yes, he says that he saw motors like this in an old tape something(player or recorder, i dont know, he doesnt remember).

So how can I make use of these other two terminals? Any ideas? Trial-Error steps?

 

That motor is simple to operate.
You give 12V to ± inputs.
The other two are High and Low, they are used for high speed recording modes.
With 12 V applied you have to give another voltage to either H or L.
U can use a 470 Ω 0.5W resistor from 12V to H or L.
Low will give a low rpm and H a high rpm.
I hope you did not damage the motor by jumping voltages between the pins.

 

I became really mad and I did jumped the voltages among everything

Anyways, thanks

 

THat could be a bipolar stepper motor , which normally comes with 4 wires!
Check the continuity b/w 4 wires.