Run Away Cart on Wide Open Throttle

[Sergio]

The Curtis 1219 is a Series Controller.

From Your description and voltage readings, it appears the Reverse Contactor is sticking Closed.

You must also be experiencing a throttle problem, but if the Reverse Contactor is stuck closed, the HPD may not do any good if all it does is prevent the Forward or Reverse Contactors coil from energizing.

[ThreeCW]

Originally Posted by kgsc

3CW, What you have is a sepex setup.

I double checked the Curtis specifications and confirmed that my Curtis 1219-8405 is a SERIES controller.

The Curtis 1268 as you mentioned, is SepEx controller, with the advancements that you noted.

[Sergio]

After reading the first post again, I missed a few details the first time...

The hard thing to explain is the Reverse with the FNR in Forward, if water was causing a Reverse input signal, switching the FNR to forward should have created an error condition (both F and R) and cause a Controller shutdown.

Even a sticky Contactor would not allow the Motor to get power if the Forward Contactor also closed.

Hopefully not water inside the Controller.

[ThreeCW]

Sergio,

Thank you for your feedback.

When I was trouble shooting my Run Away / WOT problem (on safety stands while the problem was still occurring), I unplugged the 24 pin Molex connector and function tested the Pot Box through the Molex pins. The Curtis PB-6 (2 wire) – 0 to 5000 ohm Pot Box function tested correctly with a smooth increase in resistance from 0.9 ohms with no pedal travel to 4960 ohms at full pedal depression and repeat tested with very similar results (I tested every 1/4" of pedal travel). From this I concluded the Pot Box was functioning correctly and not the cause of the WOT event. Do you agree with this analysis?

With respect to the Fwd Rev Contactor “sticking” (it is a Curtis Albright - Type SW202N-228, 48V), I completely disassembled it the day after the Run Away / WOT problem … while I was still having the same WOT symptoms with the Cushman on the safety stands. The contacts were functional with evidence of minor to moderate current arcing … there was no evidence of the contacts being completely welded together (see attached photos of REV Contactor – with descriptions in the photo name). I will post the FWD contactor on a separate post. I then cleaned up the contacts (cotton cloth only) to remove some the burn marks, reassembled them and reinstalled them in the Cushman. There was no improvement in the performance of the Cushman (on safety stands) with the WOT problem still present. I concluded from this that FR Contactor was functional and not the cause of WOT event. Seem reasonable?

Sergio – you said: “You must also be experiencing a throttle problem, but if the Reverse Contactor is stuck closed, the HPD may not do any good if all it does is prevent the Forward or Reverse Contactors coil from energizing.”

Yes, there is certainly a throttle problem … but perhaps from a difference source … could it be a shorted out controller or associated wiring due to water influx?

Sergio – you said: “The hard thing to explain is the Reverse with the FNR in Forward, if water was causing a Reverse input signal, switching the FNR to forward should have created an error condition (both F and R) and cause a Controller shutdown. Even a sticky Contactor would not allow the Motor to get power if the Forward Contactor also closed. Hopefully not water inside the Controller.”

The WOT event in Reverse occurred in all 3 direction positions – Forward, Neutral and Reverse … any time the key switch was turned on, it was motoring with wide open throttle in Reverse! Something certainly had to be shorting out somewhere! Not sure if my theory of “water entry into the controller or into the wiring ” is valid or not. Since the problem slowly went away over a period of 4 days, perhaps evaporation was my friend!

I will also attach a cart wiring diagram for reference … not sure if this Cushman is wired like other golf carts or not. I am still a newbie … but learning fast!

If anyone can suggest any replacement controller options to replace my Curtis PMC 1219-8405 (with 10 wire inputs / outputs) please let me know your thoughts.

I appreciate any input you or other readers may have … and hopefully this trouble shooting can be helpful to other readers too (perhaps on what NOT to do)!

Regards, 3CW

[ThreeCW]

Here are the photos of the disassembled FWD Contactor and the 1998 Cushman Hawk wiring diagram. Note that the FWD Contactor had significantly more evidence of arcing than the REV Contactor. Seems logical given that we drive more forward than reverse.

Regards, 3CW

[kgsc]

Originally Posted by Sergio

The Curtis 1219 is a Series Controller.

From Your description and voltage readings, it appears the Reverse Contactor is sticking Closed.

You must also be experiencing a throttle problem, but if the Reverse Contactor is stuck closed, the HPD may not do any good if all it does is prevent the Forward or Reverse Contactors coil from energizing.

You are absolutely correct. I apologize for making that mistake. Thank you Sergio for pointing that out.

[Seaquell]

I have had my cordless tool lithium batteries cut off in cold weather when I lived on the USA/Canadian border. Are the electric vehicle batteries prone to this , maybe its a safety cut out on the tool batteries to prevent damage?

Are lithium batteries a good choice in sub zero temperature areas?

[ThreeCW]

I removed the controller from my cart and found that some of the epoxy that I used to glue on the end cap and provide some addition sealing on the front plate (connection side) had cracked moderately. So it appears that the water influx theory into the controller is still a possibility. I scraped off all of the excess epoxy from the controller, sanded it down and then used a metal rated silicon caulking compound to reseal both ends of the controller ... hopefully this will keep the water at bay. I also used some silicon caulking to plug off the extra open wire slots of the Molex plug and also added some caulking around the wiring entering the Molex plug ... not pretty but hopefully it works to keep thing water tight. After assembly, everything worked ... but I did jack up the rear end and did a function test to confirm just in case I induced another problem ... safety first ! ... I didn't want to experience another WOT event!

I also had a discussion with another BGW member who indicated that I should be able to replace my controller with an Alltrax Series Controller by rewiring my existing FNR switch directly to the Fwd/Rev Contactor (instead of the using the controller to operate the Fwd/Rev Contactor).

I followed that suggestion up by reviewing the wiring diagrams on the Alltrax website and cut and pasted an Alltrax Series Controller into my existing wiring diagram. On paper it looks like it should work just fine ... I will be able to convert my 10 pin input / output Curtis controller to a 5 pin input / output on an Alltrax Series Controller.

I also made a call to the Alltrax technical support and had a great discussion. The conversion to an Alltrax controller is definitely possible ... not plug and play with my 10 pin system but not that difficult to do being comfortable with wiring. I am considering getting a SR-48500 Series Motor Controller for my 48v utility cart.

So it look like I have a way forward. Thank you to the BGW members for their assistance.

Regards, 3CW

[Alex Faught]

Alltrax make a 600 amp controller?

[Gregorio]

Originally Posted by Alex Faught

Alltrax make a 600 amp controller?

Almost. Their XCT500 can do 570 amps peak.