Unique Reverse Problem

[CCFV1982]

I have a bit of a Frankenstein project going here: I was given a 1982 Club Car 36V Fairway Villager that had been sitting for at least six years. After a thorough cleaning and deciding (from reading through this forum) that a new Alltrax system was the way to go, I ordered a conversion kit from Carts Unlimited (new solenoid, HD F&R switch 400 amp Alltrax controller, high amp cables and an FN1 switch) and installed it with brand new batteries. Nothing. After some motor troubleshooting it was decided to find a new donor cart for the rear end (better to have the newer spline motor). I was able to put my hands on a 1997 cart, discarded by a local golf club. I swapped out the rear end (differential/motor, suspension) and now have a cart that performs very well in forward, but to go in reverse I have to give it a shove. The controller is working properly in both directions, but in reverse I get some noise from the differential like it's trying, but it won't propel in reverse without a push. Once I get going in reverse it seems to do fine. Unloaded (rear wheels off the ground) it makes the same sound and "grunts" a few times but will then spin in reverse. But on the ground it just can't get going. I have read through other posts on reversing issues but most revolve around a new F&R switch. Any thoughts on this problem?

[Sergio]

Are you doing anything for reduced speed in reverse?

If You are using a micro-switch in the FNR to insert a resistor inline to reduce the throttle signal in reverse, that is likely your problem.

Of course this is assuming the Alltrax "Max Reverse Motor Speed" is not set too low.

[CCFV1982]

Sergio, no microswitch for reverse with this older setup; Alltrax is programmed for full throttle response in reverse (once it gets going it's fast in reverse).

[Sergio]

Verify your high current cables in the FNR and Controller are wired properly, it is possible that you are removing the Stator from the circuit while in reverse which would not allow the Motor to deliver torque.

Typically the Stator motor posts S1 and S2 go to the swivel posts on the FNR to make it difficult to create an issue when changing motoring directions.

[CCFV1982]

Will recheck. Thank you.

So, I reversed the F&R high amp S1 and S2 cables to check the switch itself: no change in behavior. I hooked up the laptop and double checked throttle settings on the Alltrax; all seems good. Went to monitor mode in the Alltrax toolkit to see if anything was strange when trying reverse. Gave it reverse throttle and saw 100% deflection indicated, and then the lights went out. The 250 amp in-line fuse blew. Something must be bad with the motor itself?

[Sergio]

Originally Posted by CCFV1982

Will recheck. Thank you.

So, I reversed the F&R high amp S1 and S2 cables to check the switch itself: no change in behavior. I hooked up the laptop and double checked throttle settings on the Alltrax; all seems good. Went to monitor mode in the Alltrax toolkit to see if anything was strange when trying reverse. Gave it reverse throttle and saw 100% deflection indicated, and then the lights went out. The 250 amp in-line fuse blew. Something must be bad with the motor itself?

Missed this update, it sounds more like a miss-cabled FNR.

Were the S1 and S2 cables you swapped connected to the swivel posts of the FNR, and if so did you verify they indeed go to the Motor S1 and S2 posts?

[CCFV1982]

Sergio, thanks for the reply; I missed this earlier. Yes, they are connected to the swivels and forward gear works perfectly (or, with the reversed cables, with the F&R in reverse, it goes forward just fine. I am beginning to think the differential has a problem. Again, if I give it a push to get the cart rolling in reverse, I can depress the "gas" pedal and drive in reverse all day long. But it won't go in reverse from a dead stop. It tries, but doesn't move.

[Sergio]

Wow, if it is anything inside the differential that can cause that I would be interested in understanding how it happens, I will be following...

If You have a chance next time You are working on the cart, with the FNR in neutral, You should have close to 0Ω resistance when measured between the swivel posts.

If after you get it rolling in reverse the motor still has full torque at low speed, I am out of suggestions at this time.

[Fairtax4me]

Brushes in the motor might be stuck, or worn out. If it was sitting for a long time, moisture could have got into the motor and made the brushes corrode.

Pushing the cart and it keeps going after that is the usual sign of a brush problem.

Differentials don't have anything that would act that way.

[CCFV1982]

Fairtax, thanks for the thoughts. My thinking was that it was a differential problem, and I wasn't looking forward to that repair. Brushes sound easy by comparison and this motor and rear end have been sitting for some time. Stand by. . .