Nice job pulling the motor out SD!!
Thanks for posting the pics.
Well cr@p, That doesnāt look NEAR as bad as the pictures I had in my head.
From what I see is that you lost one of your blobs of epoxy that balance the armature (remanat first pic post 21) and those look like what is left of it (the rock like bits in the second pic in post 19.)
I donāt really understand what happened in that pic (4 and 7 of 12), It kinda looks like it got hit on the edge with a hammer. Iām guessing the balance blob of epoxy rattled around and got wedged between the armature in that spot and maybe the case which crushed it into the smaller bits. Inspect your outer case half real close and look for damage to the field coils (specifically on the brush cap end).
I also see it in your pic (5 of 12) that it might have pushed up on the comm blade a bit and dismounted it (causing it to stick up a bit more than the others. This seems to have chipped and cracked the edges of your brushes.
The comm can be turned but whether the blade/finger is now loose and not reliable is the question.
The armature/rotating assy probably should be balanced again.
The hit/dent on the edge needs to be looked at to see if any of the coils are shorted to ground or itās neighbors.
The brushes can be replaced. They might even be ok to run?
And your magnet is cracked. That can be replaced. It probably created an extra pole (an extra pulse) and caused your slowdown on your trip home. (itās a theory Iām working on)
Rodney @Old_Houseboater is the expert. He will have a better assessment on this.
Loose commutator bars can be reattached. Running without reattaching is almost certain to lead to a failure.
Once a commutator bar is reattached, the commutator must be turned. After turning, undercutting might be necessary depending on the insulation height.
All in all, itās probably going to cost more to have a shop repair the motor than itās worth / cost to replace.
If the motor slows down and runs half speed or less it indicates possible open armature winding/s, There is no fix for this condition. Usually you can see the damage. I have one right now where it cant be seen but itās junk.
Just reviewed the pictures, This puppy got hot Look at the fried brush face. The commutator segment separated due to heat and centrifugal force. The armature is toast.
You were pushing 8500 plus RPM GEās cant handle that,
Are you using regen? Heavy regen on long downgrades creates tons of internal heat. More than holding the loud pedal on the mat when climbing.
@Old_Houseboater
Does the heat build up in the armature and the field? This motor has a temp probe inserted in the field windings. Maybe it threw up a warning that was not noticed, maybe there was not enough time for the heat to transfer out and trigger it.
When in Regen mode where does the energy go? Is it being dumped back into the batt bank or just some sort of flux generated heat that builds up in the motor?
I recall the original failure happened when he decided to set a new early morning speed record on a downhill. Iām guessing he had his foot in it the whole way so the car may have been leaning on the stock speed limiter (if it was still active).
Would my theory be correct on the magnet crack? (creating a 5 pole magnet)
Main buildup is in the armature. If he had any regen programmed in he can generate a lot of heat in a hurry. Regeneration turns the motor into a big high amp generator. Now that you mention it I have never seen high motor temperature indicated. 41 is controller temperature, In any event with the small tires he was pushing 8500 RPM and the motor had to have been warm to start with. Those 2 factors alone are a recipe for catastrophe. The crack in a magnet is so thin that there is no effect. on performance until it breaks. I gear my builds for 6000 on D&D and ADVANCE motors and 5000 on GE
bummer. well looks like Iāll need to look around for a new motor. what is the consensus for the best dc motor i could throw in here?
probably want to look for a 8.9 to 1 or 10.35 to 1 transmission as well.
I have some reconditioned Advance 7hp that Rodney just serviced. $450
10.35 trans and/or taller tires
Not answering the question, but do the math first.
New motor and gear swap vs a.c. motor and controller.
Iāve got a 7.5hp I havenāt seen the need for yet since I can go ~30mph and not really many hills in Pacific Beach part of San Diego. PMāed you.
@Surferdude do you still have the dead motor? If so would you be interested in selling me the end cap that has the brush housing with all the goodies in it? Iāve got too many problems with the parts inside there as well as a crack in the end cap housing.