Xct400pds- sometimes won't go after complete stop

[JohnnieB]

If you can keep you hand on the motor more than a second, it wasn't over heated and with 19" tall tires, unless you exceeded 29.5MPH, it wasn't over revved.

Might be the brushes.

Is the cart easy to push by hand? (Brakes dragging?)

[FreshFromFL]

Brakes aren’t dragging, checked that first. I did have a set of hd leaf springs coming in tomorrow, so pulled the tires off and checked everything out up close, everything looked visually ok


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[JohnnieB]

Try running the motor on 18V with tires off ground. See attached.

[FreshFromFL]

The wheels turn when jacked up at 42v still. I tested with tires on briefly with maybe 1/4 throttle.

Had no power under load when bringing it home, but would still run about 5mph, although I didn’t run it much after I felt the power loss. Only to get off the road to safe parking. I didn’t want to do any more damage.




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[FreshFromFL]

I will try the 18v test tomorrow


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[FreshFromFL]

pulled the motor and rear end today. Talked to vic with d&d and we are going to send the motor back for analysis and rebuild. Good timing with new rear springs that had just come in today. Cleaned everything up, checked bearings and brakes and everything looked surprisingly good! Cleaned up and now we wait....


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[FreshFromFL]

Talked to Vic today, and we need a full rebuild on the motor. Stated field amperage was getting too low. I need to dial in my field map and settings better and protect them motor after this $450 rebuild. I am running the field map specifically for this motor. Called and left a message with alltrax today, hopefully they can help me to get it dialed in.

Vic did say that he is concerned with the cart running that speed at 42v. He said I should be around 20...is this liability driven?

Any field map and settings recommendations would be greatly appreciated.


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[JohnnieB]

Did Vic mention what the minimum recommended Field amps for an ES-76-51 is at 42V?
(At 48V, it is 3A minimum for 100A or less of armature amps, but I don't know if it is higher, or lower, or the same at 42V.)

I suspect their main liability concern is more warranty issues than how fast the cart will go. If the field mapping is able to reduce the field amps too low, the motor will run hotter than normal and can be damaged.

Apparently there are a lot of newly written field maps for XCT controllers. They weren't available when I switched from a DCX to and XCT controller, but I did try two different maps, EZPDS and ES76-51
Max RPM for my ES-76-51 motor with 17" tall tires at 42V was 6450RPM with EZPDS and 6994RPM with ES76-51, however that additional 2.2MPH came with a huge increase armature amps.

The following is the average armature amps vs field amps while the motor is spinning between 6000RPM and 6500RPM
EZPDS = 54.4A Arm vs 2.1A Field
ES76-51 = 101.1A Arm vs 1.2A Field

It takes nearly twice as many amps to go <1% faster, so a lot of motor heat is produced.

I probably should go back to EZPDS, or maybe one of the new maps, since I've got the XCT set to limit the motor to 6500RPM.

[FreshFromFL]

He said they should never drop below 2, but he would like to see me keep them even higher than that. He said at 2A your seeing sparks.

Said he couldn’t comment on which field map to select, but he would click the turbo setting off


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[JohnnieB]

Turning the turbo off in a XCT-PDS (or other flavors of the XCT that have a speed sensor connected) also decreases low end torque, so try to find a field map that stays above 2A of field current with turbo on.