Help - Current For Stepper Motor Driver AM882 - ProTuner

[Clive S]

I'm using Leadshine's AM882 drivers on 3N.m steppers and am at the point of tuning them all up using Leadshine's ProTuner Software. What I can't understand is the current/phase is stated at 2.1A but can't for the life of me work out if the amp setting in ProTuner is asking me to put in the value per phase or the total value required by both phases combined. I'm running these drivers/steppers at 68v.

Like Neal has said if they are 8 wire steppers then I would use them in a parallel configuration as you will get more torque.
I run AM882 drive on my router at 3. something A with twin screws and 68V PS. Steppers are happy at 60'C and above.

[Neale]

Those motors sound very like the ones I bought from Zapp around 10-11 years ago - described as Nema 24 as the case is just a little larger than '23. To reassure you, mine were used on my mk1 router and are now in use on mk2, still running just cool enough to hold (= almost but not quite too hot to hold!)

Mk1 router was MDF, built in a hurry for a special job. All the structural integrity and stability of cold-rolled cow dung. Mk2 is welded steel. I suspect that your mk1 will also lead to a much-improved mk2!

[PaulP]

After some time away from the workshop I have finally got some info to report back with.

OK first off one by one I rewired the motors in parallel and set the amps/phase according to the chart given for the motor after that I tuned them all upto remove the resonanse issues. Now they sit idle and are much quieter and I'm now confident that their torque is much more suited to my setup. I tried a cut at 5mm deep in Trespa (HPL) at 3000mm/min without any problems other than the expected noise from the cutter. It didn't skip a step and the final part was as expected.

As for the dust boot I tried the 3d printed skirts in PLA but if you're thinking of replicating it I'd say don't bother, it didn't work. PLA might be stiff but it's still too brittle, maybe another material might work but mine went into the bin. I work in a business that does plastic fabrication so had a decent offcut of clear flexible PVC sheet, the sort you see hanging on doorways. I ended up using that with 8mm strips cut in to act like the bristles would have done. It works well enough but I'd still say bristles would be better but maybe I'll do that at a later date with some 0.15mm paintbrush bristles.

If anyone is interested the machine allegedly pulls just over 3 amps from the socket which is slightly confusing given the amps being pulled by the spindle on the VFD is showing as 3.3a. All devices were powered from the same socket so that might need a bit of investigating. Without the spindle running it shows 2.3a when all 4 motors are running at rapid speeds.

So all issues are now resolved, for now. There will be more to follow no doubt but until they show up I'd like to thank everyone for their help and assistance on the all of the above.

[Kitwn]

Getting sensible measurements of current with the sort of pulsed waveforms you find around VFDs and stepper motors is not a simple matter. Many meters are designed to work with either fixed DC or purely sinusoidal AC and will give missleading results with anything else. Have a look at the spec for your VFD and exactly what the displayed current is meant to represent. As long as the numbers are in spec for the device and nothing is getting uncomfortably hot I would suggest not loosing too much sleep over the exact readings and how they relate to each other.

Kit

[GuitarCNC]

Hi everyone,

I have been struggling for weeks to build a serial cable to connect my AM882 drives to Protuner.
Would anyone provide the actual pinout of their cable? That would be so appreciated!!
I got the pinouts that are floating in diagrams all over the web but none work.

I had made this cable years ago and all was working, but I have lost that cable.
I am using the same PC which is dedicated to Protuner.

Thank you so much in advance.

[JohnHaine]

Assuming that the current tuning is setting the winding current then the supply current from 68v will be much lower as the drivers in effect are switched mode PSUs.