Curtis 1268, Erratic Regen Braking While Driving

[Bulk-Head]

Hi guys, need some help with a cart that has me pulling my hair out. It's a 2009 Ruff & Tuff with a 48V Curtis 1268-5403 controller, and ADC motor. The problem I'm having is its got an erratic throttle or regen issue, the cart will cut out at random times while under way. I've reduced the Max Regen CL to the minimum and that helps soften the jerkiness, but I've yet to find the real problem. The fault history has 'Main Contactor/Fuse Open" and a 1,2 "Throttle" fault. There is no main fuse, at least that I've been able to locate through fairly exhaustive searching, and the contactor isn't opening when it happens. It has a 5V throttle assembly, which I replaced, as well as the speed sensor, and the brake pedal micro switch. The throttle is operating with expected voltage values for a good throttle, both through the pedal range and when it shutters. Using the controller software I can see during operation that the cart's going into regen momentarily when it jerks/shutters, but have not been able to locate the source of the issue. Batteries are good. I'm down to it being an internal controller issue, or a short in the wiring harness.

Any ideas?

Thanks.

[mjroman20]

What is the actual voltage range of the throttle at pin 13 of the controller? Value at fully up and fully depressed? The 1268s have 4 voltage settings for the throttle: fault low, fault high, 0% and 100%. the 0 and 100% are the actual armature PWM start and end points for the throttle. The fault values are triggered if you exceed the high or drop below the low. These may need to be tuned in.

An perfectly functioning MCOR on a 1268 for example reads about 0.4volts at rest and 4.7volts at fully depressed. So the 0% value is set to 0.5 with the 100% at 4.5. and a fault low of 0.3 and fault high 4.8. These fault values provide a wire-off protection for pot-type throttles but if you have a voltage pot that actually goes from 0-5 you may need to set the fault values to 0 and 5.

[Bulk-Head]

Originally Posted by mjroman20

What is the actual voltage range of the throttle at pin 13 of the controller? Value at fully up and fully depressed? The 1268s have 4 voltage settings for the throttle: fault low, fault high, 0% and 100%. the 0 and 100% are the actual armature PWM start and end points for the throttle. The fault values are triggered if you exceed the high or drop below the low. These may need to be tuned in.

An perfectly functioning MCOR on a 1268 for example reads about 0.4volts at rest and 4.7volts at fully depressed. So the 0% value is set to 0.5 with the 100% at 4.5. and a fault low of 0.3 and fault high 4.8. These fault values provide a wire-off protection for pot-type throttles but if you have a voltage pot that actually goes from 0-5 you may need to set the fault values to 0 and 5.

Range is around .2V on the low end 4.3 or 4.4V on the top end. I have the alarms set at 0.00V on the low side and 5.0V on the high side, Max and Min basically, so they shouldn't be causing the alarm. I've been busy and haven't had a chance to look at anything else, but I'm leaning toward it being a short in the harness, maybe the controller is losing power momentarily, perhaps a faulty ignition switch, or short to ground or B-.

I've also wondered if there could be a problem with the throttle supply voltage coming from the controller, but I've only got digital multi meters and I don't think they're fast enough to catch anything out of the ordinary, that is, if there's even something wrong with the supply V. I've got an old school analog panel meter on order and should be able to see the needle sweep or fluctuate if there's a problem there.

I've turned the RegenCL down to 50A, and that's tolerable, but you can still feel the controller freaking out occasionally. Anyone have a opinion on whether or not this could damage the cart if we continue to operate the cart? Also, could this be a problem with the brushes?

Thanks

ETA: Yes, it is indeed the 5V, non pot throttle.

[mjroman20]

I suspect that the type of throttle you are using is probably the issue. It would need a direct 5V and GND connection, the throttle high and low pins on the 1268 have 453ohm resistors inline with them. This could bottleneck the current draw for the throttle and cause some intermittent results.