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SnapAmp Stepper Motor Diagnostic Tutorial

Shown below is a plotted motion of 400 cycles (1600 full steps) with quite gradual acceleration up to a velocity of 255 cycles/sec (1000 sps).

A noise from the motor is heard during about the middle half of the motion. Here the motor position and current in both stepper coils is plotted.


Zooming in on the beginning of the motion shows nice current waveforms 90 degrees out of phase.


Here is a plot of the Velocity and the commanded output Voltage of one of the coils. Note how as the Velocity increases the lead compensation (set at 55) increases the amplitude. Referring back to the first current plot above we can see that the current amplitude is maintained at about 1.4 amps throughout the motion. Showing the lead compensation is set properly.


Zooming in on the current waveform at around 1 second where the motor noise seems to begin.


Zooming still further at 0.98 seconds where the odd behavior seems most pronounced.


Current Waveforms with no Lead - Current drops and motor immediately stalls.


Zooming in on the initial stall region.