three phase motors to steppers

[Steven Gorkowski]

Hi Bob

Thanks for the info . If you need big power fets contact me off line I
have some to spare.

kb4mxo@ mwt.net

Steve

bamcknig at postoffice.syspac.com wrote:

> steve
>
> Several years ago I was trying to use alternators for stepper
> motors and variable speed motors.  I managed to get Don Lancaster  a
> little interested and he wrote it up in one of his many columns.
> One reply was from a guy using them to control a wood lathe.  He made
> up a video of his work which was very well done.  I don't remember
> what devices he was using, but the controller was physically large.
> I have been waiting for some low voltage Hi current mosfets, but that
> doesn't seem to be the way industry is going.   All the devices I am
> familiar with are in the under 100 watt range, or are much higher
> voltage.  The drivers have been around for ages, but getting them to
> control some power seems to the problem.  At High voltage and high
> prices, there seems to be a wealth of devices.  I seem to be twixt
> and between.
> I'm not sure how a three phase induction would work as a stepper.  My
> immediate reaction would be to use it as a servo with feedback.  The
> alternators were nice in that you could control both rotor
> current,for torque, and your field for speed or position.
> I ended up putting some steppers on my mill.
> The 72 rpm slo-syns can be used as steppers if you don't want a lot
> of speed.  They got gobs of torque and they are cheap.
>
> This is all off the top of the head, if you want more details, I'll
> look a little deeper.
>
> Bob McKnight
> Phx AZ