OT: Stepper motor drive circuit....

[derekm]

Any one here have the circuit diagram and construction details of a stepper motor drive of around 42 volts DC, 3 phases, 500hz and a total of 900W from 240V single phase.
No its not for a CNC but for part of project I'm building in my shop.

I can work the frequency drive from a special PIC microcontroller. Its the drive circuitry.

btw Its a controller for a Turbomolecular pump. This forms part of high vacuum set up I building...

I got the pump in pallet of junk I bought at an auction for £30... I dont want to spend £500 on the controller .

[alanganes]

Are you certain that is a stepper motor? We have some turbomech pumps where I work, they all use brushless DC motors.

I'm not saying that is the last word, just tossing out a bit of food for thought.

-Al

[Evan]

It sounds like a regular 3 phase brushless motor to me. It could be a 3 phase variable reluctance stepper. There isn't a lot of difference in the drive requirements for either.

[added]

A 3 phase variable reluctance stepper motor is easy to spot. It has no permanent magnets and no armature winding or brushes. It has no holding torque at all without power and free wheels when power is not applied. It is wired in a wye configuration the same as an AC induction motor with a common and three coils. In reality the three coils may be several in series or parallel internally but externally it will appear to have just three windings that all measure the same to common.

[derekm]

my biggest problem is 40+ pin connector and no wiring diagram for it.