# Need advice fixing a AC Motor



## 67BGTEV (Nov 1, 2013)

I've AC31 famously-aka AC45 that was running fine until I went for a 10+ miles drive (my first longer drive).
The Max speed I went on this is 45mph and it started making this noise while regen' I towed it home and dismantled the battery and motor.

PLEASE don't use this post to bang Al - it was not meant to be for that, but I need your help.
Here is the video





Sound is coming from the front of the motor (other end of the motor-shaft and coupler)

We couldn't figure out:

what caused it
where is it rubbing against
bearing is misaligned
how to fix it

I know there are few motor experts here. Would you be able to lisen to the noise and diagnose?

How can I fix this? Can I open the motor, how to open it?
If I need to take to a local Motor specialist, do you recommend a place in SF Bay?


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## steven4601 (Nov 11, 2010)

Those motors are pretty simple, taking it apart should show what is going on.
Theres very little that can go wrong by opening it as long you have a clean working desk and keep thick towels under the rotor to prevent dents / dings on the surface.


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## Ivansgarage (Sep 3, 2011)

Some thing does not look right on the rotor fins.

Remove encoder first.

Take it apart, care full removing the encoder, take off cover,
encoder pickup, tiny allen screws to remove wheel, now take motor apart.


Ivan


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## 67BGTEV (Nov 1, 2013)

Thanks Steven, Ivan. Will give it a try and let you know how it goes.


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## electro wrks (Mar 5, 2012)

I'm guessing the snap ring on the output shaft of the motor is missing, broken, or forced out of its groove. This would allow the armature to be pushed back into the motor, with the aluminum fins on the end of the armature contacting the motor back plate. It looks like there's broken and bent fins on the armature. The plate that holds the motor output bearing in place could be bent or broken with the same results


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## madderscience (Jun 28, 2008)

did something go wrong with the adapter plate and/or coupling, or are these parts of incorrect dimensions, and this put way too much end force on the motor shaft causing the damage described above?

Or, if there is a lot of backlash/end slop in the input shaft of the MG transmission, if you were to downshift or roll down hill in gear, would it shove the input shaft of the transmission forward and put excessive end force on the motor shaft?

(having had a couple british trannies apart, I know they can have a lot of slop in them; look for worn or failed thrust bearings)


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## 67BGTEV (Nov 1, 2013)

EW, MS,
Both of your assessments are correct. Coupler is rubbing the body of the motor. I guess down shiftinging may have forced the shaft out of its place. The allen screws keeping the coupler were loose.
Tranny in my MG is from 240z.
We are thinking of putting some padding between adapter plate and bell house, so that it gives little bit of room.

We didn't open the motor.


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## 67BGTEV (Nov 1, 2013)

We looked at the motor very carefully and it appear to be AC35.


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## onegreenev (May 18, 2012)

I see you figured out the issue. No, its an AC-31 motor. It was built by HPEVS and is no longer available nor supported by HPEVS. Might consider some blue locktite on those allen bolts. Don't use Red. Why did you go clutchless?


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## 67BGTEV (Nov 1, 2013)

onegreenev said:


> I see you figured out the issue. No, its an AC-31 motor. It was built by HPEVS and is no longer available nor supported by HPEVS. Might consider some blue locktite on those allen bolts. Don't use Red. Why did you go clutchless?


Thanks for the suggestion. I'll use the blue locktite. 
I wanted to reduce the weight and keep it simple. I'm not planning to shift too often. 
My friend has AC 35 and we are converting my car at his place. We did look at the both the motors very closely and the pictures of AC 31. The one I've is def AC 35, though I don't have a way to prove it.


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## Ivansgarage (Sep 3, 2011)

This is from HPEVS http://www.hpevs.com/catalog-ac-31-ebay.htm
BUYER BEWARE!!!!

It is our understanding that there are AC-31 motors being marketed as an AC-45 motor with the Curtis controllers (1238-6501) on eBay. The AC-45 identification is erroneous as HPEVS has not built a motor with this moniker. The frame of the the motor listed as an AC-45 motor is the AC-31 motor with the AC-31 labels removed.

In Addition, the eBay seller is now displaying our AC-35 motor graph with a title of AC-45 in bold black letters! "The HPEVS AC-35 Imperial Peak Graph" moniker was written over with the AC-45 moniker! AGAIN, this graph is of the AC-35 motor!! Open our graph below and compare it to the numbers that are on this sellers listing for which we have attached a copy! Please note the resemblance!! 

And now (4-28-14), the seller is trying to sell the SAME AC-31 motor as an AC-46 motor and as a Dual AC-46 motor! No matter how you package it, the motor is still an AC-31 motor!!

The listing states that the motor is capable of obtaining 70 horsepower and 130 ft .lbs. of torque. THIS INFORMATION IS INCORRECT. The AC-31 motor was originally designed to run at 72 volts and at 550 amps (Curtis controller 1238-6501) and produces 32 horsepower. This design was for vehicles under 3000 pounds at 25 miles per hour.

Some have had success with this set-up in light weight highway vehicles.

The power graph below shows the actual horsepower capability of the AC-31 motor when used with the Curtis 1238-6501 controller . The Curtis 1238-6501 controller has a nominal voltage limit of 84 volts.

The AC-31 motor is electrically different than the AC-35 and will NOT have the same performance!

We STRONGLY recommend that you do your research before making ANY motor/controller purchase!


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## onegreenev (May 18, 2012)

67BGTEV said:


> Thanks for the suggestion. I'll use the blue locktite.
> I wanted to reduce the weight and keep it simple. I'm not planning to shift too often.
> My friend has AC 35 and we are converting my car at his place. We did look at the both the motors very closely and the pictures of AC 31. The one I've is def AC 35, though I don't have a way to prove it.


If you got it from Al on an ebay AC-45 purchase you most assuredly have an AC-31. 

The AC-31 and 35 both share similar attributes in size and weight. The differences are how its wound internally. The AC-31 was designed for light weight vehicles of less than 2500 lbs and for speeds not to exceed 25mph. Thats not saying it can't do better with a larger controller but the motor is still wound for lower voltages and lower speeds. The AC-35 was designed for larger vehicles and for higher speeds like you'd see in a small to medium automobile. Still should not exceed 3000 lbs even with an AC-35 but they were designed for on road vehicles. The only way to check is open it up and count the windings and check the diameters of the winding wire. With a good controller the AC-35 is hard to beat. the AC-50 is good as well but heavier but not much extra for the extra buck. So the Dual AC-35 is a killer deal. Super high torque and excellent voltage range if you use the 144 volt controller and even if you stick with the 96 volt 650 amp controller you will rip the tires off your vehicle with a dual setup. I know of one such setup going into a caddy in my area. Super nice fabrication build. It will be a sleeper for sure. It will be coupled with a modified power glide transmission and I believe he has the 96 volt 650 amp controller setup. I might be wrong there so I guess I should ask. 

Anyway let us know the outcome of the build and performance of the motor. I don't trust Al but I would more trust someone else to give an opinion and real results good or bad or just so so. 

If you have ever been in a vehicle with an AC-50 you will soon realize if your motor is up to snuff. 

I have been in two with AC-50 motors and the 96 volt system. 

Pete


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## electro wrks (Mar 5, 2012)

Getting back to your motor issues: Glad to see in your latest vid that the motor appears to be minimally damaged. Even with locktited (a verb soon to be in the OED) set screws, the coupling (that's what the manufacturers and seller call them) still may move around. It looks like the motor shaft is 1 3/8"(1.375") in dia.? Standard 1 1/4" pipe has a ID 1.380 dia., so you could make a decent spacer out of pipe to go between the coupling and the snap ring to keep the coupling from grinding on the motor housing. Then again, the coupling could work its way the other way and start chewing on the release bearing support.

Verified proper alignment (no more than 0.003" misalignment, if the published ICE flywheel and crank run out limits can be used as a guide) and a tapered bushing based coupling design may be the best solution.


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## 67BGTEV (Nov 1, 2013)

Thanks everyone for the suggestions. We drilled couple of threaded holes and created a small notch on the coupler so that the screws hold the coupler in place. Loctited them, it's in place nice and tight. Alignment was not right and stared to make some grinding noise. We were able to fix that and put it back in. Everything's good so far. Drove about 25 miles with max speed of about 50mph. It's handled well, good to take it back on the road. 
Next step: 
tune the controller, so that it drives the way i like it
Connect the J1772 to AVC and make it ready for public charging


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## electro wrks (Mar 5, 2012)

In one of your latest videos, the coupling look very loose on the motor shaft. This could make it very difficult to achieve proper alignment. Is the shaft 1 3/8" dia. or 35mm ( they're very close)? What caused the grinding noise and how did you align the set up to eliminate it? Do you have any pics/vids of the latest set screw fix?

So many questions because I'm considering a Datsun PU with a similar motor/trans. setup


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