A bipolar stepper would only have four wires. An 8-wire motor *could* be
a unipolar stepper that does not use common tie-points for the coils.
(In most unipolar steppers, there are two coils, and a center tap
between each coil, for a total of six wires).
The rubber pinch roller suggests to me this isn't a stepper motor. If
some machine designer is going to use a stepper motor, the most typical
approach is direct drive of something -- they want to ensure whatever
they are driving is being moved a certain number of revolutions. This
isn't possible with a punch roller.
It could *still* be a stepper, but it's something to look into. Also,
the results with the meter are inconclusive. I take it all other wire
combinations showed an open circuit?
It's possible this is a DC motor with a tach or some other similar
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