"Is there a preferred method for troubleshooting these drives, like mega-ohm readings on motor windings?"
AVGTech, what problem arises that provokes you to troubleshoot the drives? Please be specific..
I think your referring to diagnostic testing for magnetic coupling? simply, take the winding resistance and refer it to the recommended resistance on the manual.
If you had a problem with the drive itself, an operational check will leads you to diagnose or troubleshoots the drive.
Simple ways to determine any abnormalities are; DC output to the coupling, unresponsive of speed when rheostat is activated, open winding at the coupling, etc.
"Whenever you are asked if you can do a job, tell them, certainly I can! Then get busy and find out how to do it." Theodore Roosevelt.
The problem that occured which drew my attention to the coupling, was an intermittant speed variation, no change in controller output, and no shorted leads on the eddy coupling, just random speed changes, sometimes a slight rise , most often a slow down, no faults present, then it would just pick and run again. sometimes for hours. finally bought a spare controller and sent the motor and coupling out to be tested and checked, never changed controller, vendor said windings in coupling had a problem but they didn't show a problem with a simpson, when it came back it ran perfect.
