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Author Topic: twinned motors; 2 sharing 1 driver  (Read 7083 times)

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Re: twinned motors; 2 sharing 1 driver
« Reply #10 on: August 24, 2010, 10:13:38 PM »
Hi stirling

Sorry my ignorance, and time to response your answer, but I din't receive any email message from Mach forum. I didn't know about your answer.

Really my steppers are 8 wires, pull out from dot printers, I think they are 12volts 0.75A

My CNC controller only can drive  5,6 and 8 wire steppers,  4 wires is not possible. It's a HobbyCNCPro four axis controller capable to drive four  3A stepper motor in each axis.

Sorry I don't understan whats the meaning of *starving*. English is not my native lenguage, and Iam not capable to understand many words like this one.

I believe that you told me that this connection of two steppers in one axis will not burn my controller because is a chopper drive.. is ok until here?

And bad results can be that current *starving* my motors....┬┐What meaning this phrase?

Thanks in advance for your help

Regards

Rene

Offline stirling

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Re: twinned motors; 2 sharing 1 driver
« Reply #11 on: August 25, 2010, 07:52:48 AM »
Hi Rene

Sorry - I missed the fact that your drivers are unipolar.

What I meant by "starving" is "hambriento" (I think). If for example you had 3A motors and 2A drivers then your motors would be "hambriento" for 1A but no damage would happen because the chopper drive wouldl limit it's output current to it's maximum of 2A.

But anyway, your drivers have a maximum of 3A and you'll only need 1.4A for your two unipolar wired motors in parallel (if you're correct about thei motor's phase currents). Just make sure you limit the current of the driver to 1.4A. There should be a way of doing this on your driver board - usually either by changing a current sense resister or via a dip-switch.

Anyway - good luck - like I've said, I've done this on several systems and it's allways worked no problem.

Cheers

Ian

Re: twinned motors; 2 sharing 1 driver
« Reply #12 on: August 25, 2010, 12:19:47 PM »
Hi Sirling, thanks for your help
Can you send a diagram for connect both motors in paralell.?

I suppose that I must  too set Vref in controller for two motors in this way (0.75A x 2)= 1.4A x 0.1 = 0.14volts
using one stepper will be 0.75A x 0.1= 0.075volts

I think that if max current in both stepper is less than 3A, steppers will not be "starving=hambrientos" of current

Thanks in advance

Rene

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Re: twinned motors; 2 sharing 1 driver
« Reply #13 on: August 26, 2010, 10:56:21 AM »
Can you send a diagram for connect both motors in paralell.?
Just wire the second motor into the same connector exactly the same as the first motor.

I suppose that I must  too set Vref in controller for two motors in this way (0.75A x 2)= 1.4A x 0.1 = 0.14volts
using one stepper will be 0.75A x 0.1= 0.075volts
I don't know anything about what Vref is on your driver so I can't help you there.

Cheers

Ian
Re: twinned motors; 2 sharing 1 driver
« Reply #14 on: August 26, 2010, 01:26:55 PM »
Two motors off one driver?  Is this for concurrent operation like maybe for two z-axis to cut two pieces concurrently?  Why not just use a timing belt between the two?  Set it up with a clutch on the secondary axis so you can disengage and spin it to match.  If its for some other purpose then obviously my suggestion is a waste of electrons. 

Online Tweakie.CNC

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Re: twinned motors; 2 sharing 1 driver
« Reply #15 on: August 27, 2010, 02:15:37 AM »
I think you have just wasted some electrons Bob.  ;D

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: twinned motors; 2 sharing 1 driver
« Reply #16 on: August 27, 2010, 11:24:11 PM »
Hi

Bob La Blonde, thanks for your suggestions
Really, Iam trying to get more torque
because I will use a small steppers pulled
from dot printers. Your advice could be useful
if my steppers are more powerfull

tHANKS

Rene