Dual Motors of one driver.

forgottenCNC
Posts: 34
Joined: Mon Jul 30, 2012 6:36 am

Dual Motors of one driver.

Post by forgottenCNC » Fri Aug 10, 2012 10:51 am

I was thinking the other day that I really needed to make a dual motor system for my Y axis because the other side was just "floating" to much for my liking, the first thing that came to mind was Fleming's left had rule because I didn't have any additional drives to drive the motor. So I connected the 2nd motor coils in reverse to the motor on the other side and what did you know it ran in the correct directions (in reverse) from just one motor driver.

Here's a quick overview of how to connect things.

From shield >>Motor 1>>Motor 2
RED-----------RED----------BLUE
BLUE----------BLUE--------RED
BLACK--------BLACK------GREEN
GREEN--------GREEN------BLACK

Image

Image

Image

Image

baz
Posts: 115
Joined: Thu Jun 21, 2012 9:02 pm
Location: Yorkshire, UK
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Re: Dual Motors of one driver.

Post by baz » Fri Aug 10, 2012 10:20 pm

That's interesting stuff, thanks. Did you experience any power loss on the motors? (I am no electrician, but I though the current is halved?) I was also impressed by your build, the way you had tucked the cables within the MakerSlide was pretty cool, and your belt clamps are clever as well. Do you mind sharing your experiences with those, do they restrict travel or not? (you have a different belt configuration so that might help)

Many Thanks

Regards

Baz
ShapeOko #676, eShapeOko #11, Hardened MakerSlide, OpenRail, Steel v's, Misumi Extrusion, Kress 800
MakerSlide Europe Store

edwardrford
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Re: Dual Motors of one driver.

Post by edwardrford » Sat Aug 11, 2012 3:15 am

forgottenCNC,

Really nice setup you have going there! Looks a lot like how my personal machine is configured :-)

1.) Love the cable through the X axis makerslide. That really cleans up those wires.
2.) Really like the micro wire wrap. Again, really cleans things up.
3.) Thanks for the left hand rule! I have unhooked my dual drives several times and each time had to use trial and error to get it back in sync. I'll remember now, just reverse *ONE* pair :-)
4.) For the low-pro belt clamps, did you use the buildlog belt clips as inspiration? (I'll post the link when I find it)
5.) @baz: Yes, sharing a driver does half the current to each motor. However, 60oz/in is enough to push the machine (take the X axis for instance). We still have that same torque capacity, but it's spread over the width of the gantry with 30oz/in (theoretical) on each side. Works great. Like I said, my machine is run the same way.
6.) If you want to clean up the back belt connections (instead of using the insertion nuts). Have a look at the zip tie method. They both look and work better.

Awesome work!

-Edward
Shapeoko 1 #0 - a couple of upgrades.
Shapeoko 2 #0 - a couple of upgrades.
Shapeoko 3 #2 - Stock

forgottenCNC
Posts: 34
Joined: Mon Jul 30, 2012 6:36 am

Re: Dual Motors of one driver.

Post by forgottenCNC » Wed Sep 19, 2012 11:51 pm

Hi Guys,

Sorry for the delayed response, been investing my time into my primary project/hobby ( http://code.google.com/p/slide-33/ ) which is by the way the reason I got a ShapeOko.

The current in the circuit is not halved - as by connecting the motors in parallel you are changing the inductances (lowering it) seen by the driver this allows more current to be sourced (or sink ) by the motor driver because thier is less total inductances in the circuit.

Where the power loss does come from is the fact that the voltage drop across the motors has to be shared when in parallel this basically means they are now 12 Volt motors not 24 Volt motors.

The belt clamps are indeed buildlog clips from the Maker store. I got myself a camera slider for their a little while ago. As for them limiting travel, if you trim about a mill of one side there is no issue.

The only warning I would give to people if they run two motors of one driver is to keep the wire length of both motors the same to the junction point (node). The reason I say this is because micro stepping uses phasing techniques and as a result of this you need the same point of the wave form to reach both motors at the same time.

BrianH
Posts: 27
Joined: Sat Apr 28, 2012 1:51 am
Location: Raleigh, NC

Re: Dual Motors of one driver.

Post by BrianH » Thu Sep 20, 2012 3:55 pm

Cool Project. I have a piece of makerslide that I've set aside for doing a timelapse slider....one of these days....too many hobbies :)

Also, I only had to reverse one of the windings of the stepper motor. Swapping both windings did not change the direction in my setup.
Motor 1>>Motor 2
RED----------BLUE
BLUE--------RED
BLACK------BlACK
GREEN------GREEN

cvoinescu
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Location: Camberley, UK
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Re: Dual Motors of one driver.

Post by cvoinescu » Thu Sep 20, 2012 7:15 pm

BrianH, that's correct. There are three things you can swap: you can swap the wires of one winding, the wires of the other winding, or swap the windings themselves. If you swap one or three of those things, your motors reverse. If you swap two of them (or zero), they don't. This is why, if you have 4-pin connectors wired A1, A2, B1, B2 (A and B are the windings), inserting the connector backwards reverses the motor (it swaps all three things). If your wiring is A1, B1, B2, A2, then flipping the connector over does not reverse the motor (you swap only two things). You typically want the former, because it's useful to be able to reverse your motors.
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

SnapFracturePop
Posts: 67
Joined: Fri May 04, 2012 5:13 pm
Location: Davenport, IA

Re: Dual Motors of one driver.

Post by SnapFracturePop » Fri Sep 28, 2012 4:15 am

Thanks for posting this - very helpful. I should probably point out that the steppers currently for sale at Inventables aren't the same steps per revolution as what came with the kit. That was somewhat annoying to find.
Shapeoko #384: dual-Y, outside-belt, ACME-Z,1000mm Y, drag chain cable management, insert-nut style base board, 800mw IR laser cutter, & 3d-printing with Qu-Bd & Printrboard.

JimHung
Posts: 31
Joined: Wed May 30, 2012 9:27 pm

Re: Dual Motors of one driver.

Post by JimHung » Fri Sep 28, 2012 11:41 pm

SnapFracturePop wrote:Thanks for posting this - very helpful. I should probably point out that the steppers currently for sale at Inventables aren't the same steps per revolution as what came with the kit. That was somewhat annoying to find.
I'm very glad you posted this, I was all set to try this mod with a full set of parts bought from Inventables - this would have really put a crimp on my day to find out. Is this the correct motor (400 steps/rev)? - http://store.makerslide.com/index.php?m ... 147qfvn4b2

Has anyone tried this with the GRBLShield v3 shield?

Jim
Shapeoko #: 564

SnapFracturePop
Posts: 67
Joined: Fri May 04, 2012 5:13 pm
Location: Davenport, IA

Re: Dual Motors of one driver.

Post by SnapFracturePop » Sat Sep 29, 2012 1:10 pm

I don't know when they changed - I was in the first Inventables batch. I'm going to put the new one on the Z axis so I've got a matched pair on Y.
Shapeoko #384: dual-Y, outside-belt, ACME-Z,1000mm Y, drag chain cable management, insert-nut style base board, 800mw IR laser cutter, & 3d-printing with Qu-Bd & Printrboard.

Max Metz
Posts: 240
Joined: Sun May 20, 2012 11:55 am

Re: Dual Motors of one driver.

Post by Max Metz » Sat Sep 29, 2012 2:30 pm

My 4th stepper arrived from China on Friday, I got it direct from the manufacturer by following the web address on the original motors themselves, I just quoted the model number on the motors and that's exactly what I received - us$20 including post to Australia. Stoked, I can complete my build. :-)

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