how to check charging rotor

[volcom8877]

how do you check the ohms on a rotor? where on the rotor do you touch the testers to?

 

[xjwmx]

You take the brushes out and put the probes in the holes the brushes were in so that they contact the two copper rings. The holes will be too deep for the probes. I wrapped a wire around the probe and put the wire in the hole. You have to make good contact because the resistance is so small ~5 ohms.

 

[littlebill31]

I think there is also a video on youtube for testing the rotor.

 

[volcom8877]

awesome.. thanks guys

 

[XSLeo]

When you do the test, touch the probes together. Remember this reading, this is the resistance of the test leads. Now touch the slip rings. Subtract the first reading from the second to get the actual ohms.
One of my meters reads .8 ohms touching the leads. If the slip rings read 5.9, then I subtract the .8 from the 5.9 and get 5.1. Yours can read different. My other meter reads .1 ohms touching the leads.
If you can't get the probe in the brush holes you can remove the brush holder, gives you more room. Adding extra wires can make it harder to get a good reading.

 

[gggGary]

being lazy I remove the inner brush, stick a drywall screw in the hole and put my probe on it's head. the outer ring is easily accessed with a probe. This probably violates seven of the major electrical laws but gives me the same readings as when I remove the stator later.

 

[xjwmx]

I would do that too, but I don't do drywall, plus by the time I'm frustrated enough to check the rotor I don't have enough wits left to be able to tell which ring goes with which hole

 

[xjwmx]

But since we're going into excruciating detail, I did try a nail but it had some clear insulating coating on it to keep it shiny. Probably came from a little blister pack targeted for women to buy from the grocery store.

 

[littlebill31]

Gary, that's also illegal in 42 states.