Hi, I have a few small motors I got from an old DVD player. I have no idea what voltage they are rated for so I tried one of them but failed. At first I tried 2 AAs. The motor did some clicking but no movement. So I decided to use 9V/500mA regulated down by LM317. Using a pot I slowly increased the output voltage from min to max but no movement from the motor - only the regulator became hot and smelled badly (they say thermal overload protected, blow-out proof in the datasheet). I lost patience and connected the motor directly to the power source (or at least I think so - solderless breadboard, you know). But still no movement of the motor.
Possible conclusions I have made:
9V is too low voltage
The motor is damaged
It was not connected properly in the last experiment
I know motors eat most current when they are stalled. Is it possible to damage motor by undervoltage? (Because it has not enough power to start spinning -> it drains too much current -> it becomes damaged?) Is it possible to damage motor without it being hot? If I apply too high voltage can the motor blow instantly without even trying to move a bit?
With just 2 wires it certainly seems to be a DC motor.
Have you tried measuring the resistance between the two wires - that's not so easy with a motor, but try rotating it a little (and very slowly) by hand to see if the resistance changes.
TomGeorge:
Hi,
If you google rf-300c-11440
You get this.
OMG thank you for the link. I have a few a bit larger motors from an old printer and I didn't manage to find datasheets for them - I tried quite hard with all combinations of numbers and letters found on them. I not even tried this time.
Anyway. Is slowly increasing voltage and measuring temperature of the motor (touching it by hand?) the right way if datasheet cannot be found or is there a better way?
When trying to move the motor's shaft by hand it is difficult. I guess electrical damage cannot do it - maybe the cat damaged it mechanically when playing with it?
EDIT: I measured resistance of the motor with my DMM. It showed 12 Ohm. But even when I try to help it with my hand it doesn't start rotating.
jremington:
You probably destroyed the motor with this experiment.
No. I intentionally used the small regulator as a crude current limiter. I may have damaged the motor by connecting it directly to 9V but hardly until it was connected by the single LM317. Today I used 3 LM317s in series to get more current and when I helped the motor it started rotating. But it was rotating slowly and soon stopped and became warm. Also it was able to rotate in one direction only - even with voltage switched ;-). Since it is quite hard to rotate it by hand I believe it was damaged mechanically: I had it on a wardrobe to be hidden from our cat but he got to it and found funny to knock all small items down.
EDIT: I apologize to the cat. It looks like I damaged the motor - there were screws to hold the motor in place. I screwed them back not to loose them and they were to deep - slowing down and possibly damaging something inside the motor.
