Thanks for the answers! The 0.88A motor driven by 1A definitely makes sense. I have since switched the drivers.Would you generally pick the closest rating below what the motor is designed to run at, no matter what? Even if that (in this case) meant dropping from 0.9A to 0.6A for the 0.88A motor?
That problem aside, I am still confused by the heat generation in the 2.8A motors. I did all my early experimenting with the max 3A driver (set to 3A - should have paid more attention to that too!) and the 2.8A motor never even turned noticably warm.
Now I am definitely planning on adjusting the current ratings down, but decided to compare the two drivers for a 15 minute idle session out of interest.
Driver A set to 3A - 2.8A motor - stays coldDriver B set to 2.37A - same build 2.8A motor - turns warm (not hot, but definitely noticable)Maybe I am missing something fundamental, but I just can't quite work out what that could be due to. Would that imply that one of the drivers is supplying more or the other driver less current than their jumper settings indicate?