Setting VRef on original Xylotex 3-axis board

I have (I think) the original Xylotex 3-axis board from many (10?) years ago. It is old enough that it required 24 and 5 volt inputs, it didn't have a DC-DC to make its own 5V onboard. You can see in the enclosure I have adapted that I'm using a DC-DC to get the 5V.

I ordered the board with a set of three motors. The motors are Powermax P21NSXC-LSS-NS-03. The motor tags say 1.75A on them. The kit came with cables. The motor connectors seem to have eight conductors, but the cables have four. It appears that the cable connectors have been configured so each of the conductors is wrapped around two sequential pins on the motor.

I was studying my Xylotex manual, and it said the VRef should be set for motor current * 1.44. Well, I'm not sure I ever did this, it has been ten years after all. And I figured it probably came set form the factory. But nonetheless, I decided to check. I disconnected the motors and got my digital meter out.

The way the board's pots are currently adjusted, X measures 3.33v, Y is 3.40, and Z is 3.39.

But the motor current (1.75A), and multiplying that by 1.44 should be a VRef of 2.52?

So the question is, am I set too high and should I decrease the VRef?

I read that setting the current higher than the motor's rated value will only limit the motor's speed, it doesn't increase torque or anything. So no incentive to use a higher VRef?

I also read that running higher current may cause a motor to overheat, but I don't think my motors have ever gotten particularly hot. But, I haven't run it a ton, either.

But I could be missing something, so I thought I'd come here and ask before I make any adjustments.

Thanks in advance.

Are you sure the motors are wired bipolar series, and not bipolar parallel? If wired parallel, they'd be rated at 3.5 amps.

If they are wired in series, then I'd lower the VREF to the recommended settings.

My motors are 2.3 amps and I have my VREF set to around 3.0, I think (It's been about 6 years since I set it up.

Mine is in the box with the PC, and I power mine with 5V from a HDD connector.

You are probably correct, Gerry. I'm trying to find documentation that would show me the way the Molex connector would be wired if series vs. if parallel, but google images isn't being kind.

Is there an easy way to tell?


EDIT: I actually started a new thread here: http://www.cnczone.com/forums/steppe...rs-wiring.html

Because I figured I am really asking questions now about motors and not so much about Xylotex controllers.