Motors are weak and run cool - setting up a "Leadshine" drive
 

I'm working through a couple of anomalous behaviors.

I have leadshine clone drivers and fulling steppers.

http://i3.photobucket.com/albums/y58...5stepper-2.jpg

My power supply is delivering 52v. My drivers are set for 6a peak current.

My gantry frequently jumps the rails because one of my X steppers misses steps.

My cutting speeds are slow because of this. However, my steppers are barely lukewarm after a half-hour of operation.

I intend to reduce the x acceleration and (now that I've gotten an unrelated computer problem solved) increase the microstepping (I'm currently at half-stepping)

My question is about the motor temperature. If my steppers are not overheating, is it safe to set the peak current higher? (the driver's maximum is 8a)

Since you set the currents for 6A, I assume that you did wire the motors "parallel"?

Is your SW4 on the drive switched to "ON"? (in the off position, the output current is halved)

Try connecting just one set of coils, motors might heat up - but there will be no loss of steps.

If memory serves, they're wired unipolar. When I indicated that the drivers are set for 6a, I meant 6a peak or 4.3a RMS. (1-0-1)

Is that right? I assumed the rated motor coil currents are RMS.

I should probably not be lazy, I should cut the shrink tube off the wire at the motor ends and verify the wiring scheme. I suffer from CRS.

And yes, sw4 is off: the idle current is halved after 10 sec of inactivity. I'll change that to "on" since motor heating is obviously not a problem.

The way I read their document, SW4 is not related to current reduction during inactivity (0.1 sec, not 10 sec). SW4 seems to be a total current reduction irrespective of the activity and this will explain your cool under-powered motors.

RMS vs Peak is very seldom used in specs for stepper motors, and strangely enough "duty cycle" is never discussed either. I suppose we should strictly be talking RMS - if we wanted to talk peak then we need to know how long the peaks are (duty cycle).

Thanks Gerald. I set SW4 to on and it does seem to help.

Or at least I was able to run a problematic program in its entirety without annoying crashing/banging noises, the motors did get warmer and the tool did return to zero. :)

I'm going to try higher micro stepping resolution next.

The higher stepping resolution is probably the place to start. Remember to change change your "Steps per (inch?)" value in Motor Tuning. Suggest you go for 2000 steps per revolution, which will put you on a par with everyone using gecko's. (SW5/6/7 on, SW8 off).

This will allow slightly higher accelerations, and means you can tweak the whole of the motor tuning.

Then, lastly look at motor temperatures and current.

EMC has a function which measures computer latency. That latency plus the timings of the drives chosen serves as a speed limit of the installation. My computer has had a recurring intermittent latency which made me hesitant to go to really fine microstep resolution for fear that I'd exceed that speed limit and lose steps.

It seems that I've resolved that latency problem, so I changed to 2000 steps per revolution. What a difference, (in sound at least). Much smoother and quieter. My resolution is now 4800 steps/inch.

Due to a low corner speed combined with dinky pinions, I'm still limited to about 260 IPM though. I have some replacement pinions which will allow 320 IPM or so, but I haven't yet installed them.

Since resetting SW4, changing microsteps and increasing acceleration, my motor temps are about 45°c.

As always, thanks for your help Gerald.