# Warp 11 dead A2 post



## DavidDymaxion (Dec 1, 2008)

Some local EVers and I were helping a fellow converter wire up today. It looks like he is close to getting his electric Porsche 911 on the road.

We figured something was wrong when we couldn't get the motor to turn with a battery and jumper cables. I could spin it by hand, so it is not binding mechanically. It would draw 0 Amps and the battery voltage would not change. It appears the A2 post on his motor is dead. With an ohmmeter to A1 and the brush wiring I would get low resistance. It showed infinite resistance from A2 to any of the brushes wiring. It seems like A1 should hook up to brushes 180 degrees apart, and have low resistance to those, and high resistance to the other 2 sets of brushes, which would hook up to A2. Is that right?

What could cause this failure? I was thinking maybe the A2 post twisted, and that twisted off a wire?

I'm thinking one could drop the motor, pull off the brush end cover, and hopefully it would be obvious what to fix. What are the hazards in doing that?

Thanks in advance for advice!


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## EVfun (Mar 14, 2010)

You almost certainly have diagnosed the problem. I don't know what motor you have but have some general advice (sure is a lot easier to do this on my beach buggy!) 

You need to lift the brushes up before you pull the end bell off. Usually, they can be supported by having the brush springs rest on the side of the brush instead of the bottom. That is a lot easier than pulling them to get them off the commutator. 

On many motors there is a spring behind the bearing on the end of the motor shaft. The bearing at the power end is locked in place and the other one is able to move back and forth in the end bell a little bit as the motor expands and contracts from heat. The spring holds a little preload on the bearing and often looks like a wave lock washer in a large size. Watch for it on the way apart and you can hold it in place with some dots of grease when putting things back together.


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## DavidDymaxion (Dec 1, 2008)

Many thanks, those are valuable tips. I'll post up when we figure out what it is.


EVfun said:


> You almost certainly have diagnosed the problem. I don't know what motor you have but have some general advice (sure is a lot easier to do this on my beach buggy!)
> 
> You need to lift the brushes up before you pull the end bell off. Usually, they can be supported by having the brush springs rest on the side of the brush instead of the bottom. That is a lot easier than pulling them to get them off the commutator.
> 
> On many motors there is a spring behind the bearing on the end of the motor shaft. The bearing at the power end is locked in place and the other one is able to move back and forth in the end bell a little bit as the motor expands and contracts from heat. The spring holds a little preload on the bearing and often looks like a wave lock washer in a large size. Watch for it on the way apart and you can hold it in place with some dots of grease when putting things back together.


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## DavidDymaxion (Dec 1, 2008)

(cross posted to the NEDRA list)

I posted about a week ago that I helped a friend with a dead post on his Warp 11 motor. Short story: The post is broken in the middle. I would assume it should be replaced, but is there a chance enough current would weld it together again?

Longer story: The post is actually a female threaded hole, like many modern car batteries. There was no continuity between the top and bottom of the post. I looked down the threaded hole with a flashlight, and it was clear it was broken 1/2 way down. The post had pulled up a bit, and the two halves had about 1 mm of separation. We gently tapped it down with a hammer, and then the motor spun great.

To elaborate on my earlier comment, do the experts here think that passing high current through this break would weld it back together? Or is that a spectacularly bad idea? Or would you just run it and hope for the best until something broke, or put in a new post? (I'd personally lean towards doing a new post.)


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## JRP3 (Mar 7, 2008)

Interesting, a self healing post. I suppose it could happen but I think it's a long shot.


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## Guest (May 17, 2010)

A spectacularly bad idea? Replace the post.


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## DavidDymaxion (Dec 1, 2008)

Many thanks to Jim ( http://www.hitorqueelectric.com/ ) for offering a post, this is part of what makes this a great sport and a good cause! Another good deed is Warp is sending Mark a new post for free, even though he bought the motor used and was out of warranty. I'd say that's a thumbs up for buying a Warp motor and using Jim's services http://www.hitorqueelectric.com/ .

Don't crank down too hard on your motor posts!


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