Low Max RPM Alltrax XCT500 Admiral B2 Motor

[scottyb]

Originally Posted by E36Racer

That looks like the stock motor map. Email Alltrax to get the map specific to your B2

Exactly- run the B2 motor on that map and void the warranty.

[wbhess]

Ok I’ll email them tonight. Would I damage something running my cart with the map I have? Will the performance be better or worse with the correct map installed? Is it difficult to change the map? Thanks

[E36Racer]

Don’t know if it will cause damage, probably not if your just taking it easy. It should run even better with the correct map.

Also, don’t forget to break the motor in. 10 miles easy going and monitor the temps, if it gets too hot to touch, let it cool before you keep going.

[wbhess]

I probably have close to 30-40 miles on my current setup. It’s been mostly calm, flat, gravel cruising aside from a couple 3-500yard sprints. The only thing that got hot was one of my 4ga cables. They’ve since been replaced with 2ga.

[JohnnieB]

Originally Posted by wbhess

UPDATE:
Changed my settings to 4-pole instead of 8...Now my top speed is 26-27 down the slight decline and 24ish up the same slight incline. Before it was 20-22 down and 17-19 up. I must say, I am now quite satisfied with the results. I still want to go 48v for longer ride times. With 20" tires, what is the max RPM I can run my motor? Ive attached a picture of my field map..Hope this is the correct one. Thanks for all the responses fellas...I love this site.

IIRC: The max recommended RPM for a Admiral B2 is 6000RPM, regardless of tire height, which is 28.7MPH on 20" tall tires, but I'm not sure you can reach that speed on level ground with a 36V battery pack. However, it looks like you are coming pretty close to the 5765RPM set-point shown in the picture.

Get the correct field map installed (How-To on PG-9 of Toolkit manual) and set RPM to 6000, and go from there.

[wbhess]

I loaded the correct map given by alltrax. Was I suppose to see any changes in the settings? What actually changes when switching field maps? I haven’t driven it yet since changing the map. Also, is it ok to leave the usb cable plugged into the controller at all times? Even when not hooked up to my laptop?

[JohnnieB]

Originally Posted by wbhess

I loaded the correct map given by alltrax.
1.Was I suppose to see any changes in the settings?
2. What actually changes when switching field maps? I haven’t driven it yet since changing the map.
3. Also, is it ok to leave the usb cable plugged into the controller at all times? Even when not hooked up to my laptop?

1. On the controller settings page in Toolkit, it will say something other than what it was saying on the picture you posted (EZPDS-DCS-V1). Other than the Field Map Loaded name change, you won't see any changes on the Toolkit pages.

2. Whether a Series motor is a speed motor or a torque motor or something in between is cast in stone by the way the field and armature windings are wound at the factory, and the same is true of SepEX (Separately Excited) motors, but a SepEx motor's speed/torque curve can be electrically shifted towards speed or shifted towards torque during operation by weakening the field current or increasing the field current respectively. The process of changing the motor's speed/torque curve on the fly is called field mapping.

Basically, the stock SepEx motor used in a PDS cart has a middle of the road field/armature winding ratio and is shifted towards more torque at low RPM for acceleration from a standstill by sending about 30A or so through the field and as RPM increases, the field amps decrease down to about 3A or so at high RPM. Going too far with the field amps in either direction will cause excessive motor heating. (Note: I don't know the Min/Max field amps for a stock PDS motor, 30A/3A is the field weakening profile for the D&D ES-76-51 motor I'm running)

In general terms, field amps are inversely proportional to armature amps and with an XCT controller, motor RPM is a contributing factor also.

Filed maps are motor specific and if the wrong map is used, overheating can occur and performance may suffer. IIRC, my cart picked up about 4MPH at the top end after I installed a field map written for my motor.

3. Be careful not to let the bare laptop end touch the frame or any bare wiring, or you'll take out the XCT controller. Use a USB cover on mine.

[scottyb]

When or rather after you load the map click on the SET box and watch the box turn from gray to BLUE back to gray again.
Then look on the controller setting page. 2 things should have changed.
1. The bold field map should read RHMOT-B2-V4 and
2. the pole setting should be set to 4 ( from stock

Hope this helps

[E36Racer]

Originally Posted by JohnnieB

1. On the controller settings page in Toolkit, it will say something other than what it was saying on the picture you posted (EZPDS-DCS-V1). Other than the Field Map Loaded name change, you won't see any changes on the Toolkit pages.



2. Whether a Series motor is a speed motor or a torque motor or something in between is cast in stone by the way the field and armature windings are wound at the factory, and the same is true of SepEX (Separately Excited) motors, but a SepEx motor's speed/torque curve can be electrically shifted towards speed or shifted towards torque during operation by weakening the field current or increasing the field current respectively. The process of changing the motor's speed/torque curve on the fly is called field mapping.



Basically, the stock SepEx motor used in a PDS cart has a middle of the road field/armature winding ratio and is shifted towards more torque at low RPM for acceleration from a standstill by sending about 30A or so through the field and as RPM increases, the field amps decrease down to about 3A or so at high RPM. Going too far with the field amps in either direction will cause excessive motor heating. (Note: I don't know the Min/Max field amps for a stock PDS motor, 30A/3A is the field weakening profile for the D&D ES-76-51 motor I'm running)



In general terms, field amps are inversely proportional to armature amps and with an XCT controller, motor RPM is a contributing factor also.



Filed maps are motor specific and if the wrong map is used, overheating can occur and performance may suffer. IIRC, my cart picked up about 4MPH at the top end after I installed a field map written for my motor.



3. Be careful not to let the bare laptop end touch the frame or any bare wiring, or you'll take out the XCT controller. Use a USB cover on mine.

JohnnyB, thank you so much for posting this. I never understood how the maps worked and why they are different for each motor.

I also use a USB cover on mine. I imagine if it fell on a terminal the controller will let out the magic smoke and that’s probably not a warranty item.

[wbhess]

After installing the correct map, my cart has slowed back down to 21mph on the same stretch of road where I achieved 27-28 the night prior. I had the rpm turned up to 6000 whereas before I had it turned back to around 5700. Pack voltage is 37.2. Everything else has stayed the same. Any ideas on why it is back down to its original speed?