RXV very slow

[djahern69]

Thank you.
Will check voltage again tomorrow. Water level is good. All plates covered.


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[usgicollector]

Check it under load also please.

[nickdalzell1]

snail's pace (1mph) if it also makes a sort of grinding noise I'm betting encoder bearing failure. Handheld won't throw a code at all.

We have those so often on the older RXVs i've been able to diagnose it just by the symptom.

[djahern69]

Thank you.
I presume the motor will have to be removed to check this bearing or can it be done in situ?
There is a kind of juddering when it moves at this slow pace. It moves freely when in “tow”.
Would it move freely in “tow” if this bearing was damaged?

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[Steve390Gold]

Originally Posted by djahern69

...I have an electrical background but with little to no experience with d/c....

The rxv uses a 3phase AC motor system deapite the DC power supply. :)

The grinding sound with movement is very suspicious especially that it leaves and the cart moves easily in tow mode.

If the brake was toast it would do the same thing in tow mode. Ditto for any bearing issues. Makes me suspect issues with controller or motor. Check that the appropriate wires are on the appropriate terminals of the controller U on U, V on V, and W on W.

Was the cart messed with by anyone since it was used last?

[djahern69]

Thanks for your input.
I just downloaded the service manual for it this morning and gathered it is a 3 phase motor. Testing on that should be straightforward.
I’m inclined to suspect the controller or motor too. As you said, brake or bearings would affect movement in tow also.
I guess I’ll just have to get it home to my workshop to investigate properly.

Is there any specific way of testing the controller?


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[BobBoyce]

The slow creep is indicative of a bad motor speed encoder bearing. The bearing itself may be fine, or not. But it sounds like the encoder part of it is not sending signals to the controller. Try unplugging and replugging the motor speed encoder lead from the main harness connector. It'll be a 4 conductor harness connector that is coming from the top of the motor.

Bob

[nickdalzell1]

Yeah the bearing isn't the part that fails it's the encoder part. I've done many and every time, the bearing moves freely but somehow refuses to send the controller and it does the grinding and extremely slow movement. The encoder acts like the speed sensor.

On the Curtis they moved to a much easier inductive speed sensor but when it fails (don't get those wet!) the cart just slams on the brake and almost throws you through the windshield.

The motor does have to be removed from car, and on a bench you remove the four bolts that hold the motor together, remove the brake, snap ring and wave washer, and tap with soft hammer the end until it pops off. Armature might stay on the bearing but most of the time it separates quite easily. Bearing/encoder is held in with four phillips #2 screws with another holding a cable clip. Tap bearing out and install new and put everything back together. Be mindful not to forget the wave washer, without it it will reach top speed and suddenly act like an out of balance washer (don't ask how i know lol!)

[djahern69]

Thanks nickdalzell1
I have the motor out and disassembled.
I must source the encoder bearing here in Ireland. Probably won’t be an easy task.
Would you have a rough idea on price?


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[nickdalzell1]

We get ours for around $162.95.