Re: [CAD_CAM_EDM_DRO] what would you feed this motor?

On Monday 16 February 2004 10:18 am, Ron Thompson wrote:

> That is what I was getting at. Since you have ID'd the coils, read the
> resistance and power appropriately. I'd start with 5V and no more than one
> amp. Powering with a 7805 regulator does this without dropping resistors.

I sure have plenty of those handy... :-)

> If the motors become too hot to lay your hand on add some resistance to
> drop the current. Steps are hard to see. I taped a bread bag wire tie to
> the shaft like a second hand on a clock to give a better visual indication
> of a step as I powered each coil by hand trying to figure the relationship
> of the coils.

Good idea. There *is* a mark on the gear, I'm guessing it's a "timing mark"
or similar, that I used to guess at what the step size was, but your idea
sounds good too.

> These are usually pretty forgiving as long as you don't go
> nuts with the amperage. Smoke is not a good sign.<GRIN>

Yep, we all know what happens with this electronic stuff when you let the
magic smoke out... :-)

> I have been down this road a few times and have never found the coil order
> to matter much, or else I was extremely lucky.

I forget where, but there was one web site that gave a pretty easy way to
find out the "proper" sequence. Something like apply power to one winding,
then to another -- if it moves, you've found the next one in the sequence,
if it doesn't, then you try a different one. Since this thing has two tapped
windings that's only two I've gotta try, and the rest is easy.

> After having said all that, steppers are pretty cheap on ebay. It may be
> worthwhile to just get some with known ratings. If you can keep the
> amperages below an amp or so, they are cheaper to drive. Good luck!

The thing is, I can't justify spending money on this stuff at this point, and
I also have this whole big box of motors that I'd like to do *something*
with, even if a lot of them are smaller than what you guys are probably into
using with much of this machinery...

I'm also not that ambitious when it comes to what I end up with. Maybe a
square foot of work area if that, half that for z-axis travel, and I oughta
be in good shape. I don't have the room for anything much bigger anyhow.
I've been thinking more and more that the place to start is this big old
daisywheel printer I have sitting in storage, only this time around I leave
much of the mechanism together and use it as is, and find out what the
voltages are on _those_ motors before I start working up my own driver for
them...