RE: [CAD_CAM_EDM_DRO] Re: Power Supply for 4-axis CNC stepper driver

Hi Dave,

I'll stop here. I think you said you had 2.4V motors at 6A per phase which
you worked out to be 28.8VA or watts.

Let's use the 25x rule and then say you need that 60V supply. When you can
demonstrate that a 60V, 28.8VA transformer can run your stepper motor at
full torque and full speed with the same performance as a 240VA transformer
I'll buy you a beer. (BTW the 240VA comes from 6A * 60V * 66%). It also
has to be able to hold 70.7% of full motor name plate oz/in torque at least
two step positions which can be a real life scenario.

Oh yes, and the transformer isn't allowed to let out any smoke.

John Dammeyer


Wireless CAN with the CANRF module now available.
http://www.autoartisans.com/products
Automation Artisans Inc.
Ph. 1 250 544 4950

> -----Original Message-----
> From: CAD_CAM_EDM_DRO@yahoogroups.com
> [mailto:CAD_CAM_EDM_DRO@yahoogroups.com] On Behalf Of turbulatordude
> Sent: Friday, September 09, 2005 11:09 AM
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: [CAD_CAM_EDM_DRO] Re: Power Supply for 4-axis CNC
> stepper driver
>
>
> <snip>
>
> > If you stop stepping and just hold at full torque the chopper
> circuit will
> > hold the current at 5.5A or the LR circuit will drop 57.7V
> across the
> > resistor and 2.3V across the winding. Let's see.... 57.7V + 2.3V
> == 60V *
> > 5.5A is 330VA. The chopper circuit needs to supply 5.5A too but
> from a 60V
> > supply.
>
>
> I think since we are talking chopper, we can break this into two
> parts. The first is resistors, does not apply here. The second,
> choppers....
>
> " The chopper circuit needs to supply 5.5A too but from a 60V supply."
>
> This would mean that 5.5A in the time slices as directed from the
> comparitor. it would still be PWM, maybe based on 20kHz or some such,
> but it would be at a 9% duty cycle, no ?
>
> So, it would be 5.5volts and 6 amps (33 watts) or 60volts and 0.55
> amps (33 watts)
>
> Dave
>
>
>
>
>
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