2008 e2, INWO Chevy Volt pack, Rodney’s rebuilt D&D blue 7.5 hp motor. I’ve owned it 13 years and it is run several times a week year round.
About 7 miles into my ride running about 25 mph and motor quit. Coasted off the road and cycled ignition switch, parking brake, master power and tried all drive modes - no response from motor while cycling accelerator after each of these attempts. Tried slight throttle, full throttle and pumping pedal. Nothing from the motor so called for a ride home.
Error code 81 momentarily flashed 3 or 4 times while doing the above. No other codes have been displayed while troubleshooting. Read all the posts related to error 81 and made a ‘to do list’.
Cleaned and tightened battery, controller and motor connections. Disconnected, cleaned and reconnected connectors for speed sensor (didn’t reinstall INWO MM to eliminate it as a problem), 23 pin on the controller and PSDM. Removed speed sensor and magnet is in good shape and tight.
Speed sensor test. Red to Black 10.5v , Green to Black 4.8v to 0 to 4.8v while rolling cart.
Motor doesn’t smell burnt and seems to turn freely when I rolled the cart for sensor test but got strange readings when I ohmed it out. I rolled the cart a bit to change motor position and took the following readings again with very little change.
A1 to A2 - 12 Mohm; F1 to F2 - 1 ohm
Case to A1 - 44 Kohm; to A2 - 6 Mohm; to F1 - 172 Kohm; to F2 - 173 Kohm
F1 to A2 - 10 Mohm; F1 to A1 - 224 Kohm; F2 to A1 - 226 Kohm; F2 to A2 - 12 Mohm
The display is normal with no errors and shows speed when rolling cart. Main contactor makes and breaks when it should. It will not move when the speed sensor is disconnected.
What motor is this? It sounds like the brushes are stuck or flat worn out.
Clip meter leads across A1 and A2 then
KeyON
Brake Down (Verify Brake light on Dash goes out)
Press pedal (verfiy the MC claps closed).
a. Check to see if V climbs relative to your pedal press. (Y/N?)
If yes then-
b. when released, V should rapidly drop to near 0v. (Y/N)
If Y then N, Pull motor check brushes.
(Take pics of any carnage found)
Rodney’s rebuilt D & D blue 7.5hp motor. Probably has 5,000 or 6,000 miles on it since installed.
Brake light goes out when brake is released. MC closes when pedal depressed.
Reads 37v when pedal is not depressed. As soon as I start depressing pedal the MC closes and voltage momentarily goes to 0 then 73v. Voltage continues to rise from 73v to 79v when pedal is floored. When pedal is released voltage drops back to the 37v it initially started at. It never drops to near 0v when pedal is released.
The brushes are under the perforated cage on the end of the motor, correct? Should I use some type of cleaning fluid (contact cleaner) or just compressed air to clean it up?
Yep. This sure looks like brushes.
Depending on your abilities and what is in your toolbox, this may/may not be a simple job for you.
At least start with pull the motor, remove that cage/cover and see what is going on in there. You will see a coiled up spring with a foot pressing on the back of each brush. Lift the foot, then gently grab the brush with your fingers and see if it slides in/out of it’s holder easily. (Don’t use tools as the pressed carbon brush tends to chip easily).
If you have compressed air, give it a good clean out. Sometimes a stuck brush can be unstuck with concentrated blast around its edges.
Do this outside, hold your breath, and stand upwind.
It will be a while until I can pull motor and check brushes, bigger mountains to climb. I will report back with pics when I get to it. Also it’s too hot in Central TX to spend much time in the garage. The garage rarely drops below 90 degrees. I appreciate your help.
I couldn’t wait for cooler weather - had to see what is going on in there. The cable from 2 of the brushes is burnt/melted off the brush. One brush is broken, upper left of second picture. The commutator is discolored, third pic, but doesn’t seem to have any grooves worn in it. Rubber bumper on order but have to find a source for brushes. Probably start with Rodney since I got the motor from him, unless you know of a source.
The grease seal on the gear box is not leaking and the teeth on the shaft and coupling show no wear nor weird wear pattern.
Anything else I should check with the motor off?
Will definitely wait for a cooler garage for the repair because this looks like an all day job for this rookie.
Besides the failed brushes, that commutator does not look good. It’s fixable (I’ve seen way worse) though.
As stated, shipping a motor sucks. If you’ve never trued and resurfaced a commutator and there is not a electric motor rebuild shop in your area that can do the job for la price you are comfortable with, Rodney aka @Old_Houseboater is a good bet. He’s done a lot of them, a lifetime of electric motor repairs and rebuilds to his credit actually, and he can give you tips on shipping (think plywood, hole saw for the collet, heavy garbage bags and expanding spray wall foam)
These motors are not rocket science. Most decent motor shops can deal with them locally. That is of course if you have one near you. Most major cities have more than one. However… that comm is pretty worn and looks like it has had narrow grooves cut into it by something harder than the comm material. Depends on how deep the groove are and how worn the comm is relative to its overall thickness will determine if the comm is usable. It doesn’t look great from that picture. Good luck. Might be worth just replacing the whole thing..
I agree completely Craig, You, Byron and I have all done DC motor repairs though. Profiling in new brushes is easy, you can see that on youtube or something like Hubert’s book for old guys like the three of us lol . I guess my point was if you’ve never trued a commutator before, don’t go at it alone the first time. It’s not hard, but without some experience standing beside you, its easy to fvck it up.
Yeah, you and I are lucky to have some outstanding motor shops around. Seeing that baked blue enamel that H&M uses always brings me a smile…
I think from those pictures his comm needs some TLC for sure. Brushes, oh yeah.. More than what he should try at home.
Funny you should mention H&M… I started my first controls business in the upstairs attic (tiny room for rent) of the old motor shop back in 87. That one of course burned down and the shop rebuild is much better and last I was there Bill’s son was running it.
We are lucky to have a few good shops around our area.
