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I recently bought a 3 axis table with stepper motors but no electronics.
I am trying to program it to scan an area with a gauss meter so that I can do a 3D representation of the magnetic field of the scanned object.
first things first.... I need to figure out a proper stepper motor driver for Vexta PK268-03B-C6 stepper motors. 
Could anyone recommend one? 

The label on the motor reads:

2-Phase Stepping Motor
PK268-03B-C6
DC3V  3A/PHASE
1.8deg/STEP

I have an Arduino Duemilanove, but would buy a different one if I need to....
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Sounds like a beefy bipolar motor, you want something like the A4988 but for more current.  Have you looked on ebay for 3 and 4 axis stepper controller boards, I'm sure there have been something suitable there in the past.  You want a chopper/PWM based driver that will run off 24 to 40V or so for such an application (otherwise those motors will run sooooo sllllooooooowwwlllyyyy...)

You'll also need to generate the control signals - heard of OpenCNC?
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Dubuque, Iowa, USA
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It is a very beefy motor and seems that it would be overkill just to rotate a gauss meter (assuming it's no larger than a handheld device). As you probably don't need the full torque from the motor you could try the A4988 -- if it doesn't work you're only out $12.
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Sweet... I will order some and test them out. 

Thank you
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I have used those Pololu drivers and found that they really can't handle much more than 1 amp without a heatsink and it's very difficult to attach any kind of effective heatsink to them. I would reccomend these: http://www.automationtechnologiesinc.com/products-page/kl-stepper-drivers/kl-4030-24-40vdc-3-0a-microstepping-driver. I've been using them on my CNC router for several years with absolutely no problems. And MarkT is right, use at least 24 V.
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Vexta - Is that a 4 phase or a 5 phase motor? Not real common but Vexta sold some 5 phase. Vexta made a controller that was an excellent match for that motor.
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I have used those Pololu drivers and found that they really can't handle much more than 1 amp without a heatsink and it's very difficult to attach any kind of effective heatsink to them. I would reccomend these: http://www.automationtechnologiesinc.com/products-page/kl-stepper-drivers/kl-4030-24-40vdc-3-0a-microstepping-driver. I've been using them on my CNC router for several years with absolutely no problems. And MarkT is right, use at least 24 V.

Oh, you need a cooling fan, that's a given...  something like a 4 or 5cm square cooling fan blowing through a stack of the pololu controllers might work nicely.
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Quote
I have used those Pololu drivers and found that they really can't handle much more than 1 amp without a heatsink and it's very difficult to attach any kind of effective heatsink to them

My makergear reprap kit uses these, and they do indeed get hot. I replaced the heat sinks provided with these: http://www.newegg.com/Product/Product.aspx?Item=N82E16835708011 which helped some. Adding an old computer 80mm fan inproved things again. Most useful though was the advice from their forums which was to use the little pot on the driver board to bring the current way down.
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Thanks for the link to the heatsinks, wildbill. I've been looking for an appropriate one for sometime. I'm really surprised Pololu doesn't offer these.
Yes, reducing the current limit does work but it's not a solution if you need the full capacity of the motor. These little drivers are great if you derate their capacity by about half. Using a cooling fan is a solution but for a "real world" application I would want some means of detecting fan failure which introduces extra complexity.
Having said all that it's quite likely bobby2sox's setup doesn't require the full motor power so these may work fine but that depends on how fast he wants the axes to move, the pitch of his lead screws, etc.
I would love to see more details of this project, it sounds interesting.
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Do you think it would be fine to power this up like this?  Not soldered... just with some jumper wires stick into the holes and down into some foam?

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Looks a bit flaky to me. I would solder the male headers provided with the board to the bottom side and insert these into a pair of female headers soldered to some perfboard. (I tried to insert a picture but it didn't work)
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Inserting an image didn't work so here it as an attachment:

You can also see a heatsink I fashioned out of a piece of copper sheet that clips to the driver. It helps a bit but could be better.
Be aware that the bottom of the board is utilized to heatsink the chip so setting it on the foam will not allow airflow for cooling.


* Stepper_driver.jpg (50.68 KB, 640x480 - viewed 25 times.)
« Last Edit: April 27, 2012, 12:22:11 pm by Yankee » Logged

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I have had good luck with Arctic Silver heatsink adhesive, I asked Ruggeduino if it was OK and they approved

http://www.arcticsilver.com/ta.htm

It is however a permanent bond

I used the Alumina version -- it is an electrical insulator -- no worries about shorting traces on pcb's
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