Re: [CAD_CAM_EDM_DRO] trouble shooting steppers

cadcamcenter@... wrote:

> Hi
>
> What are the proceedure for trouble shooting steppers which doesn't
> behave (eg. no reaction/hum but no movement/clicking sound but no
> movement) with
> a. only a multimeter

If you can make the software/control move exactly one step at a time,
you can pretty nuch debug it with a multimeter. but, be aware that the
DVMs may not respond accurately to signals with large pulses on
them, so if the driver is a chopping type, you may get incorrect or
even impossible readings. just reading voltage across the coils
may be enough to diagnose the problem (ie. transistor open or
shorted).

> b. frequency meter

Not much use except to count speed of step pulses.

> c. oscilloscope

much more useful. You can evaluate pulse signals on the motor
terminals accurately.
You really need to have some info on the connections of the transistors,
transistor types, etc. used in the driver.

Generally, the problems you describe sound like one winding on the
stepper is not getting any current, or is always getting current in the
same direction. Could possibly be a bad stepper (check resistance
of windings) but more likely to be a blown transistor in the driver.

Jon