Re: [CAD_CAM_EDM_DRO] Re: COMPLETE 3 axis CNC electronics package (plug-n-cut, ready to go)

Hi ballendo,

Glad you liked the post.

I haven't seen double ratings for steppers. If the same amount of
winding is driven with the same current, then one would expect the same
torque.

True, Bipolar drivers are more efficient, and simpler to wire! I prefer
bipolar drives, probably because they were the first high speed, high
power drivers I worked with. After suffering with old (70's) design
unipolar drivers, they were a welcome relief.

The technology has come a long way.

Alan KM6VV


ballendo wrote:

> Alan,
>
> Nice post.
>
> But it's only fair to mention that Bipolar DOES still have a couple
> advantages over Unipolar; even when both are chopper style drives.
>
> A bipolar drive will provide more torque to a given motor than
> unipolar. This is why we see the "same" size 23 double stack 3amp, 1
> ohm motor nowadays labeled with either 280 oz.in. (bipolar) or 200
> oz.in. (unipolar).
>
> It's also true that bipolar drivers are more efficient with respect
> to the input power required. This is due to their ability to
> recirculate "unused" power back into the supply.
>
> Finally, the bipolar drive requires fewer wires, so too fewer
> connections to pay for or go bad.
>
> Now, against that is the de facto truth that for a given PRICE, you
> can get a chopper unipolar drive with higher power supply
> capability, and higher motor amperage capability.
>
> So IMO it all pretty much averages out; both are good choices.
>
> <SNIP>
> Ballendo
>