ALLTRAX XCT500 and D&D 170-502-0001

[JohnnieB]

Originally Posted by runninrebel

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After reading it all, it appears there, was or is, some "not seeing eye to eye" between alltrax and D&D...at least as it pertains to the motor I just bought.

I haven't spoken to Alltrax, but I was going to speak with D&D first. However, based on reading that old thread I got a feeling you already know what they will probably tell me. Care to enlighten me?
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The reason your motor will not spin faster than about 3500RPM on level ground is because the field map being used only allows the field current to be reduced to about 3.0A. (The lowest recorded on the level ground data log was 2.9A)

What makes a DC motor a High-torque or High speed motor is the relative strength of the electromagnetic fields created by the armature and field windings.

For series wound motors, what type motor they are is cast in stone at the factory by the number turns of wire in each set of windings, however for SepEx (Separately Excited) motors, the armature vs field electromagnetic strength ratio that is physically cast in stone at the factory can be altered during operation by altering the amount of current passed through the field windings (a process known as Field Mapping), so a sepex motor that is physically wound for low end torque can be pushed towards more high end speed by reducing the current flow through the field windings, however doing so greatly reduces the motor's efficiency and more armature amps are converted to heat rather than torque.

As I understand it, Alltrax and others produced some field maps for D&D motors that exceeded D&D's recommended Field Weakening Limitations and some D&D motors failed due to overheating, hence the bad blood between the two companies.

[scottyb]

And some ex dealers too.

[Gregorio]

Without taking this thread sideways, who makes the maps and how hard is it to adjust them? What would happen if a customer used a generic map on a torque motor?

I have read were at least one person is using a speed map on a different brand of torque motor. Does this trade torque for speed or just increase the top speed by weakening the field to increase RPM?

[JohnnieB]

Originally Posted by Gregorio

1.Without taking this thread sideways, who makes the maps and how hard is it to adjust them?

2. What would happen if a customer used a generic map on a torque motor?

3. I have read were at least one person is using a speed map on a different brand of torque motor.

4. Does this trade torque for speed or just increase the top speed by weakening the field to increase RPM?

1. Hopefully software engineers, but could be programmers and computer code writers. You have to get to the source code to figure out who does what to whom and for those that well versed in this type of stuff, it would probably be relatively easy, but for the rest of us it is likely to be nearly impossible.

2. Might work okay, maybe less than optimal performance. Worst case is overheating, but a generic map will probably be pretty mild at both ends of the Torque/Speed curve.

3. Maps are based on motor characteristics rather than brand name, so it is possible to find a map for a specific make/model motor that would work well with a different make/model motor.

4. Field mapping is a dynamic process and the field is always weakened for more speed or strengthen for more torque. Some maps lean more toward high low speed torque applications while other lean toward high speed applications, but they can do both.

[scottyb]

FYI - I have sent motors to Alltrax for mapping and the info I get back is amazing. I'll post one clip here for JB - becuz he loves this stuff.

As you see a lot of information goes into mapping. I just sent a new Sepex high torque motor in for mapping. Alltrax has been very generous with their time to do this. It takes technicians, engineers and program writers to make this happen. Alltrax is committed to making the new Blue everybody's go to controller. The master field map list is huge & growing. We all owe Alltrax a big thank you for their work.

And, here is a field map you want to modify - LOL

[Gregorio]

Thanks JB and SB for the info. My interest is part curiosity and part need for when I do my motor upgrade. Alltrax will own the market if they continue this kind of support. BTW, do they really program in Chinese or is that just how your computer reads it?

[JohnnieB]

@Scotty: You're right, I love this stuff.

Basically, the graph posted is a data log in graphic form, so I'm not sure if it shows what criteria influences the field mapping, or just the results. On the other hand, the 32-bit CPU Alltrax uses in their XCT controller has the wherewithal to use all those factors and them some and maybe toss some AI into the mix.

@Gregorio: What you are seeing isn't Chinese, it's hexadecimal viewed in an ascii text editor. If you open it in a hex viewer or editor, you can see the actual numbers, not that it would be of much help.

The field maps are written in a high level programming language, which humans understand, and then compiled into hex, which the computer understands. To make changes, you have to de-compile the hex back into whatever programming language was used, once you figure out which one was used.

[scottyb]

I sent a map to one customer who told me he got the wrong map because the map he got was in Chinese.


I'm really having fun playing with this XCT controller. Check out my mode lock 3 personality switch. My wife can finally enjoy my cart.....in kiddie mode