# AMD Motor, FB0-4001G, 28.5HP (with speed sensor) Question



## amano001 (Sep 16, 2014)

I was planning on running it with an Alltrax 72v 450A controller. model 7245


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## major (Apr 4, 2008)

I seriously doubt those are the correct brushes for that motor. 

The process of replacing the brushes themselves takes about an hour and is easy. But in a decent application, brushes should last tens of thousands of miles. So if the brushes need replacing on a used motor, it may well need attention in other areas. Commutator reconditioning comes to mind. And then you need to break in the motor to seat the new brushes.


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## amano001 (Sep 16, 2014)

After looking at the model numbers more closely I think you may be right. That was the link the technician sent me from the EV company for the brush replacements. I sent an email asking why the brushes need to be replaced so soon also. When you break in the new brushes do you put a dummy load on the shaft to run it at the desired voltage (72v in our case) ? I read that you never want to run the motor with no load iirc. Would it be a mission to ask for pictures from them of the brushes or commutator before I decide to make the purchase. I have access to a lathe I would assume if the commutator is worn we could take a sliver off it to make it nice and shiny again? 

Thanks,
Adam


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## major (Apr 4, 2008)

amano001 said:


> After looking at the model numbers more closely I think you may be right. That was the link the technician sent me from the EV company for the brush replacements. I sent an email asking why the brushes need to be replaced so soon also. When you break in the new brushes do you put a dummy load on the shaft to run it at the desired voltage (72v in our case) ? I read that you never want to run the motor with no load iirc. Would it be a mission to ask for pictures from them of the brushes or commutator before I decide to make the purchase. I have access to a lathe I would assume if the commutator is worn we could take a sliver off it to make it nice and shiny again?
> 
> Thanks,
> Adam


Here's a good thread on the motor maintenance and break-in. http://www.diyelectriccar.com/forums/showthread.php/dc-motor-maintenance-81382.html?highlight=patina 

Might want to read up a bit on commutator turning and undercutting. Don't do it unless it's needed. The good comm film or patina is golden. Don't cut it off just to make it shiny. 

If you can't actually eyeball the motor before you buy, I'd insist on detailed photos.


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## amano001 (Sep 16, 2014)

Thank you ill take a look at it and I have requested some pictures from them. Ill let you know what they say/send!


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## piotrsko (Dec 9, 2007)

major said:


> The good comm film or patina is golden. .


Sorry to hijack, but are you talking the color of say, honey?


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## amano001 (Sep 16, 2014)

Heres some pictures he sent, I would think that golden piece is the commutator but I am used to seeing the whole circular piece so not entirely sure haha. Still waiting for response about why brushes are needing to be replaced so soon.


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## major (Apr 4, 2008)

piotrsko said:


> Sorry to hijack, but are you talking the color of say, honey?


Don't call me honey 

I used the term golden referring to patina meaning "of value", not color. The film or patina is typically a gray shade but can vary. Do a google image search on the subject.


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## major (Apr 4, 2008)

Hey aman,

Something looks fishy about that photo. Compare:


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## amano001 (Sep 16, 2014)

Everything in your picture looks a hell of a lot nicer haha. I am not sure though if my motor picture there is anything wrong or is it just dirty. 

The response for brush wear was









The customer was running a Zilla 2K at 1400 amps. High current significantly wears down the brushes. 

Thanks Major.

Do you think it would just be wise to not get this motor?


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## major (Apr 4, 2008)

amano001 said:


> Everything in your picture looks a hell of a lot nicer haha. I am not sure though if my motor picture there is anything wrong or is it just dirty.
> 
> The response for brush wear was
> 
> ...


Don't know. Looks like there were modifications to that motor. 1400A and worn out brushes don't make it a bad deal, but do indicate to be really careful. The lack of multiple and detailed photos lead me to believe the guy's hiding something.

See if you can find the guy selling these. They look like a good deal. http://www.diyelectriccar.com/forums/showthread.php?p=500818#post500818


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## amano001 (Sep 16, 2014)

Hey Major,

The company is Ev West out of california. The technician responded that there have been no mods on the motor and it only needed the brush replacements. He also is willing to drop the price by $100 due to it being for a highschool shop class.

I think its worth the risk, seems to be from a reputable company and for the price if it works perfectly will be a great project for the students.

Let me know what you think

Thanks


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## Frank (Dec 6, 2008)

I think I saw the GE motors on evilbay. On the other hand, I would probably trust EV West - they have a reputation to uphold and have some experience with these things. Ask them if they would guarantee it's in working condition upon arrival maybe?


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## major (Apr 4, 2008)

I agree EVWest has a good rep. I met those guys a couple years ago and they seem pretty good. I'm surprised they don't offer to replace the brushes (for cost) and/or supply better photos.


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## major (Apr 4, 2008)

piotrsko said:


> Sorry to hijack, but are you talking the color of say, honey?


Hey piot,

I thought of this post when I addressed a inquiry in another thread yesterday. That guy had some photos showing a motor with a well established commutator film or patina. So I thought I'd link it to your question and give the search engine another possible hit. 










Here is the reference post with a few more shots: http://www.diyelectriccar.com/forums/showpost.php?p=507722&postcount=2064


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## piotrsko (Dec 9, 2007)

Here's mine, but I thought the running at 3500 was abrading the comm too much. I'm yellow insensitive, thus the remark about the color. To me it just looks too good to be doing it correctly, but it has perhaps 100 hours on it.


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