Hi All,

I am looking for a way to drive a high power stepper motor, my current
understanding (open to correction!) is that to achieve a high step rate with
good torque you need to drive say a 8A 3V stepper with 80v which of course
current limits to the appropiate value once the emf builds up. From my
research some of the commercial units use even higher voltages up to 180v to
maintain torque at high step rates.

There seems to be a lot of info on the web but very little when current and
voltage requirement get up a bit.

I have looked at the linistepper and quite a few others and have found a PIC
based stepper driver that that does the logic conversion  but I need to find
a suitable output stage, I am guessing that I will probably need some sort
of switch mode current limiter as a linear current limiter would have a very
hign dissipation (800w!). FETs seem to be common in this area but again I am
open to suggestions.

I am also looking for a source of large stepper motors in the area of 5NM or
700 Oz/inches holding torque.

Any suggestions?


regards

Lee McLaren

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