Refurbed my motor, worked ok initially

[Mizzoulax]

Hi all,

I had a high-pitched, intermittent noise coming from my DS Electric IQ (48-volt) club car. From my research it was either the ball bearing in the motor or the brushes in the motor. Either way, I was looking at a motor overhaul which I finally tackled a few weeks ago. I think the overhaul went well (even though I broke the speed magnet several times). After I reconnected everything, I took the golf cart out for a short ride, and everything went great! Ran smooth and silent for about 6-7 minutes around the block. I returned it to the garage and put it back on the charger rather proud of myself.

4-5 days later, I decided to take it back out again. Unfortunately, nothing happened at all when I hit the gas pedal, in forward or reverse. For a few days, I would put it back on the charger and give it another attempt. At most, I got about 0.5 sec of movement in reverse. I could not always hear the solenoid clicking so I replaced it as the most likely culprit but that did not change anything.

Today, I seem to have reverse working again although I did nothing. More importantly I noticed quickly there was a plastic-burning smell and found the pre-charge resistor putting off smoke (pic included). I found this other thread (https://www.buggiesgonewild.com/showthread.php?t=128116) that I think closely resembles my problem. I checked my continuity (which was good) on motor which leads me to believe my issue is now with the controller.

Can anyone tell me if I am on the correct troubleshooting path? If so, any leads on where I could perhaps get a good used or refurbed controller?

Thanks,
Matt

[Fairtax4me]

Did you have the commutator refinished by a shop? The early IQ motors have small brushes that tend to wear the comm out and will cut some nasty grooves in it. If it wasn't perfectly smooth then it has likely already eaten the new brushes to bits.
The controller smoking the pre-charge resistor is usually due to a short in the motor or any of the motor cable terminals touching each other.
The motor needs to be removed and tested and inspected for damage.

The cables need to be inspected to be sure they are not damaged or have frayed ends.
The controller will need to be replaced but you can not install a new controller until you know the motor and cables are in perfect shape. If the motor has internal damage it will smoke the new controller instantly.

[Mizzoulax]

I did not do anything to the commutator but it looks and feels smooth as silk. I have removed the motor again and have it still disassembled as I type this. Everything looks good, not frayed cables, nothing touching. Anything else I can test or check before I put it back together? I do think I have a short here somewhere, I just can’t find it.

[Fairtax4me]

With the motor disassembled you can check the field coils for continuity. But it will need to be reassembled at least partially to check the brushes for continuity or shorting to the case.

With the armature out, it is easier to check. Use a continuity tester to check for continuity between the comm bars and the main shaft of the armature. There should be no continuity. If there is the armature is damaged.
With the armature back in the motor and brushes properly installed, Check for continuity between the A studs. You should have continuity.
Check for continuity between the F studs. You should have continuity.
Check for continuity between any A stud and any F stud. There should be NO continuity.
Check for continuity from any F or A stud to the motor case. There should be NO continuity.
A damaged field coil or damaged stud can short the controller and ruin it, and cause the pre-charge resistor to burn.

Check the motor cables for any fraying or damage. When the cables are re-installed on the motor make sure the terminal ends are clean and can not touch each other.
Use a second wrench on the lower nut on the stud to prevent the stud from twisting when tightening. A twisted stud can damage the leads inside the motor and cause a short to the case.

[Mizzoulax]

The motor passed all continuity checks with flying colors. I guess maybe the motor is not the problem? It looks really good and clean and with all this continuity testing I’m thinking it’s no longer the problem.

Should I jump to replacing the controller or are there some other checks I can do before taking that expensive leap?

[Mizzoulax]

IMPORTANT CONFESSION: When I was initially removing the engine, I did accidentally touch the crescent wrench to both the A1 and F1 poles. I did see a nice arc of blue spark. Fortunately I was not hurt as I was wearing gloves. It was only then that I switched it from run to tow mode and then properly disconnected the batteries.

I’m sorry for not sharing this sooner. I had completely forgot about that incident until now.

[Volt_Ampere]

You may have fried the controller with that stunt. Tow mode isn't enough - you do have to disconnect the battery pack whenever working on a cart.

[Tom47]

Originally Posted by Volt_Ampere

Tow mode isn't enough - you do have to disconnect the battery pack whenever working on a cart.

Expensive lesson we all need to keep in mind. There should be no short cuts taken when working on the cart.

[Mizzoulax]

Yes, I'm lucky I didn't hurt myself or worse.

It looks like a controller is not something you can simply order based on a part number from anywhere (I saw a vendor in China selling one for $150.00). Anyone know a good source to buy one?

Thanks,
Matt

[Goober11]

Give David a call https://www.revolutiongolfcars.com/. He sells stock an after market controllers.