Possible MCOR/Speed sensor issue???

[sethchid]

Yesterday I took the wife out for an evening hunt. From the time we left the barn all the way to the parking spot everything worked as it should. After we got down, I got the cart to head back and it seemed low on power. I could floor it from a stop and it would accelerate as normal but only up to a slow speed. on the whole way back, about every 50 yards or so it almost felt like we were hitting something because the motor would torque so hard like it was trying to go. It would only be a momentary bump/knock and would keep at the slow pace. It's been extremely wet down here in Louisiana this winter, and we're dealing with tons of mud and water. Any suggestions as to where to start?

[Sergio]

I see from Your signature You are running the Alltrax XCT controller, so this is really a question for ScottyB.

How does the XCT controller (when configured to use the speed sensor) behaves when it looses the speed sensor signal?

[sethchid]

That was another of my concerns. I'm not real sure if that aftermarket controller would make a difference in the performance with a bad component

[TahoeDawgZ71]

The XCT uses the speed sensor. It monitors RPM through the speed sensor circuit so it is definitely a crucial part of the system. Seth, when you plug in your laptop to the XCT does it show any faults?

[Sergio]

The behavior You described is how the stock Curtis controller performs when it cannot detect the speed sensor pulses.

It basically cuts the output PWM to 50% until it can detect the pulses again.

It would be nice to know how Alltrax handles that scenario.

[sethchid]

I will try to pick up the cart tomorrow and plug it into my computer. I didn't have my trailer with me to bring it home

[scottyb]

Originally Posted by Sergio

I see from Your signature You are running the Alltrax XCT controller, so this is really a question for ScottyB.

How does the XCT controller (when configured to use the speed sensor) behaves when it looses the speed sensor signal?

I have not experienced this problem but this is my understanding of how this could effect the operation.
In a case where the throttle signal has been lost and then resumed, the control should resume normal operation without memory or program lost. So this doesn't seem to be the case here.
In the case where the throttle signal range changes, such as might occur if the potentiometer is watered. The control may incorrectly interpret the new signal until the throttle auto-calculation was cleared ( in program mode) and allowed to recalculate a new set of parameters. Or the potentiometer was dried and returned to the original range of signal.
It sounds like there is a chance the MCOR got water in it?
Program mode would also show if the throttle signal is full or reduced.

[Sergio]

It does not look like a throttle signal problem, it is more likely a speed sensor signal problem.

If You program the XCT to use the speed sensor, then unplugged the speed sensor, how does the controller handle that, limp mode?

[scottyb]

Originally Posted by Sergio

It does not look like a throttle signal problem, it is more likely a speed sensor signal problem.

If You program the XCT to use the speed sensor, then unplugged the speed sensor, how does the controller handle that, limp mode?

OK. I'm sorry I have a cold and I'm not reading 100% of what's posted.
What happens is a limp mode. If the controller sees no RPM but is seeing throttle it’s going to give the motors field the current it would need at 0 rpm and so long as the motor is telling the controller it’s at 0 rpm the controller will continue to give the field that many amps and no more. Sometimes the motor will limp along at 7mph & sometimes they’ll very slowly climb up to 12-15mph it just depends on what motor you have.

[sethchid]

Originally Posted by scottyb

OK. I'm sorry I have a cold and I'm not reading 100% of what's posted.
What happens is a limp mode. If the controller sees no RPM but is seeing throttle it’s going to give the motors field the current it would need at 0 rpm and so long as the motor is telling the controller it’s at 0 rpm the controller will continue to give the field that many amps and no more. Sometimes the motor will limp along at 7mph & sometimes they’ll very slowly climb up to 12-15mph it just depends on what motor you have.

Its definitely not getting 12-15, I figured 5-7 tops. Hopefully work permitting, I'll be able to pick the cart up from the camp tomorrow and plug it in to my laptop