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electrique · 07-17-2009, 04:23 AM

Help! I just finished the brakes and was ready for the road test, when after a few 100' runs and a couple of 25' reverses, the motor began to shudder, barely moving the car, (in both forward and reverse)
I checked the high amp motor connections and found the rearmost post to be loose, and upon removing the nut, found half the bolt came with it. It appears someone had over-torqued the bolt and broken it off. It had been held into the casing nut by 2 threads, and lots of rubber cement!
Thinking I'd solved the problem, I removed the motor and took it for repairs to have a new post installed.
I got the bad news when I went to pick it up. It appears that the stator had been scraping the field coils; one of the coils had a major melt into the casing;
and two of the coil segments were slightly proud, and possibly also shorting behind the coil.
My concern is, how did this happen? The motor was very secure to the drive shaft. What I find very curious, is that there is no bearing supporting the splined end of the motor, on the housing.
It appears that all the support comes from the drive shaft. Is this correct? It's a very unconventional way to build a motor, as most motors are self supporting units via their casing bearings?
If I can find another motor, how do I prevent this from recurring, as it appears that the stator has flexed in order to touch the field coils?
Has anyone else experienced this problem?
Now, ...how do I find a replacement motor....the motor rebuilder here doesn't think General Electric will sell the field coils or any parts.
Motor tag info :
Mod 5BC 49 JB 327 C M 4000
6/ 48 123
15 Min
Wound SERIES 49 cej
AMB 40 CLASS F
Serial No CS 11

All and any help greatly appreciated. I am in Victoria British Columbia.

07-17-2009, 04:23 AM	#1 (permalink)
electrique EcoModding Lurker Join Date: Jun 2009 Location: Canada Posts: 16 Thanks: 4 Thanked 0 Times in 0 Posts	Motor probs - commutacar Help! I just finished the brakes and was ready for the road test, when after a few 100' runs and a couple of 25' reverses, the motor began to shudder, barely moving the car, (in both forward and reverse) I checked the high amp motor connections and found the rearmost post to be loose, and upon removing the nut, found half the bolt came with it. It appears someone had over-torqued the bolt and broken it off. It had been held into the casing nut by 2 threads, and lots of rubber cement! Thinking I'd solved the problem, I removed the motor and took it for repairs to have a new post installed. I got the bad news when I went to pick it up. It appears that the stator had been scraping the field coils; one of the coils had a major melt into the casing; and two of the coil segments were slightly proud, and possibly also shorting behind the coil. My concern is, how did this happen? The motor was very secure to the drive shaft. What I find very curious, is that there is no bearing supporting the splined end of the motor, on the housing. It appears that all the support comes from the drive shaft. Is this correct? It's a very unconventional way to build a motor, as most motors are self supporting units via their casing bearings? If I can find another motor, how do I prevent this from recurring, as it appears that the stator has flexed in order to touch the field coils? Has anyone else experienced this problem? Now, ...how do I find a replacement motor....the motor rebuilder here doesn't think General Electric will sell the field coils or any parts. Motor tag info : Mod 5BC 49 JB 327 C M 4000 6/ 48 123 15 Min Wound SERIES 49 cej AMB 40 CLASS F Serial No CS 11 All and any help greatly appreciated. I am in Victoria British Columbia.