ok electro-geniuses...heres a tough one...

S

SkaerE

Joined
Sep 9, 2001
Messages
428
man is this wierd (at least for me)

heres the deal.

i've wired up my dc motor controller. had some issues with it, not sure what to do. BUT, here is the really odd part:

my motor spins freely (by hand) on its bearings. its spins several times, depending of course on how hard i spin it. now, when the controller is all hooked up to it, it will spin in one direction fine and barely spin at all in the opposite direction. this may be normal, BUT, it does this even when the controller is NOT plugged into the wall - it has no power to it. as soon as i unconnect the motor from the controller it spins freely again and as soon as i reconnect it, there is resistance.

what causes that? is there something wrong?

poltergeists?:eek:
 
Skaere,

A DC motor (maybe AC too?) will generate electricity when you spin it.

If there is nothing hooked up, then there is no load generated by spining it. However, if it is hooked up to the controller, then there could be a load, depends on the controller I suppose. I wouldn't worry about it.

BTW one way to test the motor is a car battery. You should be able to spin it slow in each direction at 12VDC. That would rule out controller vs. motor problems.

Steve
 
oh good,

thats much better than an evil spirit.

i already have a problem with the evil spirits. ;)
 
The motor is generating a current when you spin it. If you have it connected to the controller and spin it by hand that current is introduced into the controller output circuitry. This circuity, I am not familiar with your controller, may be feeding back that current to the motor in the form of a 'short'. I would not continue doing that. It may not hurt the motor but I wouldn't test the controller output by doing that.

Roger
 
That's common, not a problem, I've seen industrial equipment shipped with small DC motors that had a shorting bar across the terminals to help hold the machine from turning in transit. Lots of fun if you don't remove the bar before turning it on.

Most likely won't hurt anything but if you must turn things by hand, go slow.
 
Don't trust them! It's nothing scientific! It's them evil spirits! They run in copper wires, unseen, up to their evil, devious plots, they collect behind computer monitors, into CPUs, and do awful things to humans! They make you swear so that your soul will go to hell when you die, and make you die sooner out of electronic pollution and stress! I'M NOT MAD! I KNOW 'EM, I'M A COMPUTER EXPERT SO I KNOW WHAT I'M TALKING ABOUT! I'M NOT MAAAAAAD!!!! MAKE 'EM GO AWAY!!!!!!!!!
AIEEEEEEEEEEEEEE!
:D
 
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