Run Away Cart on Wide Open Throttle

[kgsc]

Originally Posted by Alex Faught

Alltrax make a 600 amp controller?

Soon.

http://www.alltraxinc.com/Products_SR.html

[Sergio]

Remember guys, he has a Series Controller, Alltrax does make the SR48600 model.

ThreeCW, that is a good choice, but like You mentioned, there will be some wiring involved.

The main issue is that the Curtis controller used the negative side to activate the FNR contactors, so You will need to re-wire the FNR switch to activate the contactors directly.

Also notice that they used the "User Mode" on the Curtis to provide fast forward, You will need to change that wiring FNR pin #4 (BR) so it provides the +48v when in Reverse to use the "REV" input on the Altrax.

The Alltrax has a "turn OFF main contactor on zero throttle" option that will be ideal for your setup since You don't have a pedal micro-switch.

You just need to make sure that the main Solenoid negative is connected to the Alltrax "NEG Solenoid Control" terminal.

[kgsc]

Sergio, I think the sr48600 is in the works based on the coming soon banner

[ThreeCW]

When I spoke to Alltrax Technical Support on June 30th, we spoke about both the SR48500 and SR48600 controllers ... my understanding is that both of these Series Controllers (SR) are are presently available ... attached is the SR spec sheet for reference.

Given that I am satisfied with a maximum speed for this utility cart of 15 mph (most driving is 5 to 10 mph) on gravel roads and pasture in moderately hilly terrain and my motor is a 6.5 hp (48v, 4700 rpm), Alltrax suggested that the SR48500 would be more than sufficient for my requirements and that the SR48600 is "overkill for most carts". So I think that I am more than adequately sized for my cart requirements. We also discussed that future upgrading to Lithium batteries would be handled by either of these controller options.

I also asked about the built in cooling fan ... it does NOT run continuously rather it is set up to engage at 70% load or 50 C, which sounds like a good feature for me.

Alltrax also suggested that it was a good idea to hook up a foot switch for safety (see attached SR - Generic Series Wiring Diagram for reference). My cart currently has a Curtis PB-6 (2 wire) pot box ... I have notice that there is a micro switch contained in the pot box but I don't believe that it is wired up ... I will have to take a closer look to determine the logistics of connecting the micro switch into the SR48500 wiring recommendations.

Alltrax also indicated that the SR Controllers still require a diode and resister to be added to the Solenoid (Main Contactor). I understand that this requirement may be different for other "Styles" of controllers, but for the SR (Series) Controllers, the diode and resistor are still required on the solenoid.

The requirements for the diode and resistor are noted on the SR - Generic Series Wiring Diagram. Of interest to note for 400 amp (or above?) solenoids, the diagram indicates that a MR754 diode is listed. For 200 amp solenoids, a 1N5408 diode is listed. I was not familiar with the MR754 diodes so downloaded a spec sheet and found that they are rated for 22 amps (1/8" lead lengths) or 6 amps for PC board applications (see attached MR754 spec sheet for reference). This compares to the 1N5408 diode (which many members may be using) which is rated for 3 amps ... but also indicates on the spec sheet "Not Recommended for New Design". I did quiz the Alltrax Tech guy and he was not familiar with this requirement ... perhaps the Alltrax design engineer going overboard ?? (my comment) ... or perhaps requires further review ?? I am pretty new at this ... up until a few months ago, I could not tell you the difference between a diode and a poppet type check valve ... today I know the difference between those two ... but not between two different diodes. Perhaps one of the BGW more technical members can offer an opinion.

Finally, Sergio:
Thanks again for your input ... much appreciated

When I cut and pasted the Alltrax SR controller into my Cushman wiring diagram, I too noted that the Curtis controller had the SW202 Fwd-Rev Contactor running at "reverse polarity" compared to the SW202 spec sheet and the the Altrax SR Controller (just the way Cushman did it ... not sure if there was a valid reason to do it other than you can go either way). I traced out the current directions and found that although the current directions will reverse with the Alltrax SR, they will reverse in both the Motor Field and Armature, so I should not have any troubles with the Fwd or Rev directions. As you stated, Fwd and Rev will be hooked up direct from the FNR Direction Switch to the Fwd/Rev Contactor.

Sergio said: "Also notice that they used the "User Mode" on the Curtis to provide fast forward, You will need to change that wiring FNR pin #4 (BR) so it provides the +48v when in Reverse to use the "REV" input on the Altrax."

Sergio, you did not likely have the benefit to see the SR - Generic Series Wiring diagram when you commented. As per the Alltrax diagram, I was thinking that I would follow their wiring as follows:
Direction Switch - Contact 6 (OR) - will go 3 places - wire directly to REV Contactor, REV input on Alltrax controller and though a diode (1N5408 - 3 amp) to the Solenoid coil "+".
Direction Switch - Contact 4 (BR) - will go 2 places - wire directly to FWD Contactor and though a diode (1N5408 - 3 amp) to the Solenoid coil "+".
Direction Switch - Contact 3 (R) - will go 1 place - to reverse alarm
Direction Switch - Contact 1 (GR) - will not used

My Cushman is currently working well by avoiding getting the controller wet ... but for safety (first!) and reliability, I am planning to replace the controller in the foreseeable future.

Regards, 3CW

[Alex Faught]

Do you ever load it down close to its capacity?

[ThreeCW]

Originally Posted by Alex Faught

Do you ever load it down close to its capacity?

On occasion, the Cushman is loaded close to capacity (1200 lb payload capacity includes occupants). 95% of the time it is used as a run around vehicle for 1 or 2 occupants and less than 100 lbs of cargo. It sure is a handy vehicle to have around. Prior to this we were using an older 2 stroke quad ... noisy, stinky, hard to start and requiring constant maintenance. Having an electric utility cart is a couple of steps up on the old quad!

[Alex Faught]

Alltrax is confident that the 500 amp controller should be sufficient at full load as well?

[ThreeCW]

Originally Posted by Alex Faught

Alltrax is confident that the 500 amp controller should be sufficient at full load as well?

Based on the recommendation of the Alltrax Tech Support, the 500 amp controller should be more than sufficient.

I was not able to determine the amperage requirements for my Cushman but here is what I was considering:

1) My motor is a 6.5 hp GE Model 5BC49JB3054 Series Wound Motor. The only thing that I have been able to find out about this motor online is that it is 4700 rpm and 19T internal spline. I am not sure what amperage that this motor draws under peak load. It more than meets my power requirements … if it ever fails, I would NOT be considering a larger motor.

2) My existing controller is a Curtis PMC Model 1219-8405 , 36 - 48 v, 600 amp with a 2 minute rating of 600 amps.

3) My cart is equipped with a 200 amp circuit breaker (auto reset) … according to the wiring diagram!

The electrical performance of the cart meets all my requirement (speed, torque, hill climbing ability, etc) except the WOT events I previously experienced.

The only time that I experienced an electrical limitation was when running up a snowy hill in the winter and spinning out with the cart due to lack of traction (chaining up solved that problem). The cart powering off for a few seconds ... then starting up again. I assume that was the 200 amp circuit breaker saying "too much amperage" ... or perhaps the controller ... not sure??

The 2 minute ratings of the Alltrax SR48500 and SR48600 are 500 and 600 amps. The continuous ratings are 380 and 450 amps respectively. Enabling the "Peak Amp Mode" in the Alltrax Toolkit program gives peak amps of 575 and 690 respectively.

So I plan to go with the 500 amp Alltrax Series controller unless someone with more experience can point out the error in my reasoning.

Regards, 3CW

[ThreeCW]

From Post #18 - July 1, 2017

Originally Posted by 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 things 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!

Just an update to close out this thread:
It has been 4 months / 30 cart hours since I experienced the Run Away Cart on Wide Open Throttle (WOT) event. And it has been 3 months / 20 cart hours since I resealed my controller using silicon caulking compound in an attempt to prevent water entry into the controller. I have not experienced any additional WOT events over the past 4 months which leads me to conclude that the WOT event was almost certainly caused by water entry into the controller.

Lesson learned: Keep water away from the controller when cleaning my cart!

I am still considering replacing the controller in the future if I see any controller related hiccup. I am also considering a future conversion to a lithium battery pack at which time I may also upgrade the controller. Thank you again to the BGW membership who provided me with advice on addressing this problem.

[Mooncarter]

Originally Posted by ThreeCW

From Post #18 - July 1, 2017


Just an update to close out this thread:
It has been 4 months / 30 cart hours since I experienced the Run Away Cart on Wide Open Throttle (WOT) event. And it has been 3 months / 20 cart hours since I resealed my controller using silicon caulking compound in an attempt to prevent water entry into the controller. I have not experienced any additional WOT events over the past 4 months which leads me to conclude that the WOT event was almost certainly caused by water entry into the controller.

Lesson learned: Keep water away from the controller when cleaning my cart!

I am still considering replacing the controller in the future if I see any controller related hiccup. I am also considering a future conversion to a lithium battery pack at which time I may also upgrade the controller. Thank you again to the BGW membership who provided me with advice on addressing this problem.