12 volt CD motor test

[Davidfarm]

Hi

My names is David.

I'm hoping you can help with my treadmil motor before the thing drives me potty. (I might have just posted this else where so if I have apols...did just seemed to disappear.)

Briefly, due to being new to the treadmill I think I under lubbed the belt and put too much strain on the motor....I was getting some slightly strange smells.

I have been advised that I have PROBABLY burnt out the motor but before I spend money on a replacement I just wanted to comfirm if poss with some checks.

I rigged up with a 12 v battery pack (and drill battery reading about 11.5v) which didn't fully energy the motor.....just seemed to make it twitch is the best description I can think of.

I also used a multi meter to check resistance. I have read it should give 30/50 ohms in the stationary position. It read 5. When I rotated the spindle it alternated between zero and over load. The brushes seem fine.

I am not discounting issues with the speed ontroller/MCB (whats the difference?)but I think the mootor is the place to start.

Any advise would be gratefuly recieved!



David

 

[telectrix]

as you rotate the armature, the resistance readings will fluctuate slightly, but you should read continuity at any position. an o/c would indicate bunt out windings. if it smells it's probably knackered.

 

[Davidfarm]

Thanks for the reply.

How much is slightly? How much fluctuation would you expect?

Sorry whats an o/c?

 

[telectrix]

as you turn it the meter will fluctuate, due to a bit of resistance on the brushes. o/c is open circuit . (O/L on meter).

 

[Davidfarm]

Yes, if you twist it slowly it reads beween 5 and 200 ohms.

If you twist it quickly it indicates over load.

Does this mean the motor is ok?

 

[telectrix]

turn slowly. at any position it should read low ohms, 5 is about right. higher readings mean bad brush contact or burnt out windings.

 

[Davidfarm]

ah!

I was gettiing 5 ohms...but also far higher, often 200/300 ohms (turning slowly).

The brushes are ok so seems to comfirm burnt out windings?

 

[telectrix]

looks that way.

 

[Davidfarm]

That's the answer I wanted.

Ta.