Cart won't go. Alltrax XCT controller Short Circuit/Output Fault

[mattadata]

Hi,

Need some help diagnosing an issue. Cart has been working fine for a couple of years. Wife drove the cart a couple of miles this morning, cart started to slow down and make some noise. She stopped and turned it off.

Now I hear the solenoid click, then motor engages for a split second, then stops.

My alltrax controller is flashing this code on the LED
1 Green and 1 Red LED Flash = Short Circuit/Output Fault

I hooked my laptop up to controller and captured the log. Looks like the following flags are set who I step on throttle: Global_Shutdown Hardware_Overcurrent
Full log is attached.

Pack has a full charge and each battery is at 8.5 Volts

What should I check next?

[JohnnieB]

I noticed the field amps went unusually high at 01:56:25 PM when in reverse.

Check the F1 & F2 cables for worn insulation where the go around the battery frame.

Also, speed column is all "0", doesn't a txt-48 have a speed sensor?

[mattadata]

It does have a speed sensor, but it won’t move more than an inch or two. I will double check F1 and F2 wires and report back.
Thanks

[mattadata]

I inspected F1 and F2 cables. No signs of wear. Anything else I should check?

[JohnnieB]

Disconnect them from the controller and measure the Ohms between the wires/cables going to the motor.

The field map loaded indicates you have an Admiral MOT-B2 or something similar and I don't have any specs on what the Ohmic reading should be for it, but the reading for a stock TXT-48 is as follows and the B2 ought to be in tnhe same ballpark.

Note, the instructions are for measuring at the motor studs and for convenience, we are measuring at the controller end of the cables, so the resistance of the cables will come into play, but if any reading is less than those given, there needs to be more investigation.

1. Set your VOM to RESISTANCE (Ω).
2. With your motor disconnected, measure A1 to A2. This must measure BETWEEN .3Ω and 1Ω.
3. With your motor disconnected, measure F1 to F2. This must measure BETWEEN 1Ω and 2Ω.
4. With your motor disconnected, measure A1 to F1. This must measure OPEN.
5. With your motor disconnected, measure F1 to motor case. This must measure greater than 5MΩ. (5,000,000 Ω)

FWIW: The Ohmic values given are what is typically read by the VOM's and DMMs we typically have available to us. The true Ohmic values of the armature and field windings are far lower, but the meters we have cannot measure values under about 10Ω accurately.

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A bad speed sensor won't keep the cart from running (at a reduced speed), but there ought to be a reading in the log if the cart moves. Maybe an inch or two isn't enough.

With cart read to drive and pedal not pushed. Push cart several feet in either direction while laptop is attached. The motor spins 12.44 times each time the rear tires spin once, so the cart won't have to be pushed very fast to see a speed reading.

[mattadata]

It all looks good from the motor. I disconnected all four cables (A1, A2, F1, F2) and measured from the controller end of the cables.

2. With your motor disconnected, measure A1 to A2. This must measure BETWEEN .3Ω and 1Ω. Value was .3
3. With your motor disconnected, measure F1 to F2. This must measure BETWEEN 1Ω and 2Ω. Value was 1.5
4. With your motor disconnected, measure A1 to F1. This must measure OPEN. Values was O.L but did fluctuate a bit.
5. With your motor disconnected, measure F1 to motor case. This must measure greater than 5MΩ. (5,000,000 Ω). Value was 8M

I also contacted Alltrax. They had me disconnect the A1 cable also. When I did that and pushed throttle, it didn't throw any errors. They said that means the controller is fine.

Anything else I can check?

[JohnnieB]

If you still have the stock TXT48 motor around, try it.

[mattadata]

No, unfortunately I don’t have the old motor around. Not sure I can talk my friends into letting me borrow their motor for a test.....

[JohnnieB]

I'm stumped.

Alltrax says the controller is good if the errors go away when the A1 (M-) cable is removed.

I don't have the true resistance values for the Armature and Field windings of an Admiral D2 motor and you don't have a Milli-ohmmeter even if I did. The A1 to A2 reading using an regular digital Ohmmeter is at the bottom of the range for a stock TXT-48 motor and it includes two lengths of cables, so it might be too low, but I don't know one way or the other.

Logically, the problem has to be:
1. In the controller
2. In the motor
3. In the A1 or A2 cables
4. In the F1 or F2 cables.

At this point, all I can suggest is substituting the items on the above list.

If you bought the Motor, Controller and other stuff from Carts Unlimited, email Scotty and he might be able to help find some way of testing motor.

[Sergio]

Just a suggestion, but You should also test A1 to Motor Case.