RE: [CAD_CAM_EDM_DRO] Re: stepper torque.....please help

First off, don't be fooled into thinking that CNC is an inexpensive
pursuit. Metal working in general is an expensive hobby and adding CNC
to it only increases the cost. My point in this is that adding CNC to
you minimill may be more expensive than the whole mill was.

Regarding series vs parallel:
Don't get all hung up and think that if you can not set up the motor as
parallel you will have terrible performance. Back before a lot of us
knew better we ran our motors in series and they performed just fine.
Knowing what Mariss from Gecko and others have now taught us we have
also learned that you can run the motor half coil and get almost the
same performace as parallel. So, you have lots of options on how to hook
it up and they will all work and get you cutting chips under computer
control. Don't stress on it.

My advise if you are on a budget would be to get the xylotex drive and
connect it to the motors in series or half coil (try one and then the
other and see how it works for you). You can run the motors on less than
the full rated current and they will work just fine. You will lose some
low speed torque where it does not matter, but your running torque at
any reasonable speed will be limited by the inductance and not the
current limit of the drive. This may not be the optimum set up for the
motors you have, but it will get you running and learning. You can
always move up to some Geckos at a later date and sell the xylotex for a
pretty good percentage of what you paid for it.

Tim
[Denver, CO]

> -----Original Message-----
> ok well how about this then........i have just bought 3 Vexta
> 305 oz- in 2 phase steppers@4.5A 2 phase excitation,2Vdc.,8
> wire and am
> trying to determine what kind of driver i can get that is not too
> expensive(ie.gecko's)
> xylotex.com has a 3axis ,2.5A bipolar driver . my question is can i
> use this driver to run these motors with a 24Vdc/12A power supply if
> i run them in series?if so , do i need to use some kind of resister
> for current limiting? and what (approx.)i know that running steppers
> in parallel is better, but i cant use this driver if i run them so.
> what would the torque then be with these motors in series in this
> setup with the xylotex driver?
> i ve also been looking at an up to 15A, 3 axis unipolar driver from
> stepperworld.com that would definately have no problems running my
> motors, but i read that using a unipolar driver is a bad idea
> considering the lower performance of it compared to bipolar drivers.
> is this true??what would the actual performance(estimated)be if i
> used this stepperworld driver compared to the other xylotex driver?
>
> i want the best performance i can get without spending more than the
> whole grizzly minimill cost to begin with. which direction should i
> go?? ive asked the same questions in the mini mill group but i have
> yet to recieve a clear and concise answer or suggestion(not that i
> can understand anyway
> any help would be great..thanks