Build Thread- 2 motors per axis

[weeli]

Hi there. Without sounding stupid, what are the complications of running 2 identical steppers from 1 driver. In my country large obsolete steppers are hard to come by. In my ignorence I thought 2 smaller steppers might help with tourqe and maybe speed. I would appreciate anny help on this matter, drivers, motors and power supply. thanx in advance.

[Haydn]

I may be wrong but I think you cant run two steppers off one driver.

[joecnc2006]

yes i have run two motors from one gecko driver during testing, but now i run two drives and two motors on the Y-Axis of my Joe's CNC 4x4 Hybrid.

Joe

[harryn]

Hi, As Joecnc2006 points out, running two motors from one drive can be done, but there is an element of "surprise" possible.

There is some chance that your motors are unipolar as well. In that case, you might want to consider using the very inexpensive linistepper to drive them. ( $ 35 / each). If you start running out of signals, here is a link to a signal splitter.

http://www.cnczone.com/forums/showthread.php?t=49838

[weeli]

HI. Thanx for reply. I built a desktop mill, X=300mm travel, Y 200MM and z=150mm. I want to do hobby cncing . Mostly aluminium work , accuracy and finish is more important than outright speed. how wil this affect choice of motors and drives. I live in south africa so kits are a problem

[harryn]

I think there is someone in S Africa that carries gecko drivers if that helps. I have seen them post - I think in the wood working section. I am not really sure how to advise you on cutting speeds for aluminum, but I think to obtain good finishes, you need to move the material fairly fast.

[CoAMarcus]

weeli,

While we never recommend running two motors from one drive, it is possible to do so with a gecko. It is covered in our FAQ, and I have the answer pasted below:

The drive can put out a maximum of 7A and 80V, which would work out to 80V and 3.5A per motor. Also, our drives have mid-band resonance compensation, which senses the rate of load change and is applied as a correction. If you have two motors on one drive, it does not know which motor to correct for. One motor would pump the other into resonance and would stall. If your speeds are less than 3 RPS or less, you can run more than one motor per drive. However, that is only 180 RPM, which is something that will probably be too low.

I hope that helps you out. I would highly recommend running one drive per motor, and running two motors on one axis with two separate drives is very easy. You wire them up the exact same, with the same step and direction signal, except on one of them you swap terminals 3 and 4. This is all assuming that the two motors are mirroring eachother, and not side by side. I hope that helps!

-Marcus Freimanis

[kiwibum]

Originally Posted by CoAMarcus I would highly recommend running one drive per motor, and running two motors on one axis with two separate drives is very easy. You wire them up the exact same, with the same step and direction signal, except on one of them you swap terminals 3 and 4. This is all assuming that the two motors are mirroring eachother, and not side by side. -Marcus Freimanis

Am I correct in thinking that running two motors e.g one for each side of the gantry would provide twice the amount of torque for moving it? E.g using two 200ozin drives would be similar to one 400ozin motor? I'm seeing a use for Geckos new 4-axis drive with a couple of 180ozin motors I have.

Thanks for your posts Marcus they are very useful and informative.
Steve

[CoAMarcus]

kiwibum,

That is correct. You would get twice as much torque on that axis. Just think of your motors as people; if you are pushing something by yourself it is pretty hard, but if your friend helps you, you only have to push half as hard as would be required.

-Marcus

[kiwibum]

Thanks Marcus. I suspected that but I confirmation is a good thing, the devil is in the details and that's where I often get caught out. Due to the money going in to this project I'm spending a lot of time reading about it all. Understanding the different drive types and issues has made me see the value in speeding money on decent drives. I'm excited about the new geckos you are working on when considering the other options available at the same price point. thanks again for your indepth replies.
Steve