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  #1  
Old Mon 25 April 2011, 07:02
pjohnsonj
Just call me: phil
 
cincinnati
United States of America
Help with wiring Keling KL34H295-43-8B steppers in Unipolar

Definately not an electrician, so I wanted to verify wiring. Here is the diagram for the stepper: http://www.kelinginc.net/KL34H295-43-8B.pdf . I want to go with Unipolar since most Mechmaters have the best success with that configuration. I will be using Geckos 203s and 3to1 belt drives. It appears from my forum reading that it should be wired as follows:

Blue to A+
Red to A-

yellow insulated/shrinkwrapped by itself
green insulated/shrinkwrapped by itself

Brown to B+
Black to B-

orange insulated/shrinkwrapped by itself
white insulated/shrinkwrapped by itself

Is this correct?



Thanks for your help!

Phil
Cincinnati
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  #2  
Old Mon 25 April 2011, 07:13
bradm
Just call me: Brad #10
 
Somerville(MA)
United States of America
Hi Phil, with the terminology nitpick that what you are doing is "Bipolar half-coil", everything looks fine. Often this confusion arises because "Bipolar half-coil" has the same electrical characteristics as "Unipolar", so we look at that spec line on the motors. Unipolar uses six wires, but only four of them at any given instant in time; Bipolar uses four wires continuously.

If you motor runs backwards from the way you wish, swap any ONE pair, such as the blue and red wires, to reverse it. Good luck!
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  #3  
Old Mon 25 April 2011, 07:23
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
That's correct.

I've found that using DIN terminal blocks at the motor makes things easy. For instance, with your motor wired half-coil, I would use an eight-terminal block:

1 = Blue = A+
2 = Yellow
3 = Red = A-
4 = Green

5 = Brown = B+
6 = Orange
7 = Black = B-
8 = White

To make that a bipolar parallel connection, I would add jumpers between pins 1 & 2, 3 &4, 5 & 6, 7 & 8.

1 = Blue = A+
2 = Yellow jumpered to #1
3 = Red = A-
4 = Green jumpered to #3

5 = Brown = B+
6 = Orange jumpered to #5
7 = Black = B-
8 = White jumpered to #7

That motor is rated at 4.3A when wired half-coil, so a 75K 1/4W resistor lets the motor pull full Amps. A 48VDC to 60VDC power supply would give you full speed. (The higher the voltage, the hotter the motor. The higher the voltage the faster the motor turns.)
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  #4  
Old Mon 25 April 2011, 07:23
pjohnsonj
Just call me: phil
 
cincinnati
United States of America
Thanks Brad! The Bipolar half-coil is what most Mechmaters are using, correct?
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  #5  
Old Mon 25 April 2011, 07:29
bradm
Just call me: Brad #10
 
Somerville(MA)
United States of America
Yes, bipolar half-coil is very commonly used; maybe even most-commonly used. It is in the "can't go wrong with" category of choices
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  #6  
Old Mon 25 April 2011, 07:31
pjohnsonj
Just call me: phil
 
cincinnati
United States of America
Thanks Richard. I like the idea of the DIN terminal blocks. Is the resistor a current limiter. What is the proper why to wire it to the driver?
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  #7  
Old Mon 25 April 2011, 07:43
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
Because you have an eight-wire motor, you can wire it bipolar series, half-coil or bipolar parallel. Those who have six wire motors only have the choice of bipolar series or half-coil.

I do not use bipolar series. Series has excellent low speed torque. It pulls the least amount of current, but it has very poor high speed torque. Those applications that need lots of torque at low speeds benefit from a series connection.

With six-wire motors, I use half-coil. It gives the same speed as bipolar-parallel and 70% of the torque of parallel. It also runs cooler than parallel.

With eight-wire motors, when I need both speed and high torque, I use bipolar parallel. It gives the same torque as series and, depending on the voltage used, gives 3X to 5X as much high-end speed before hitting the shoulder or knee portion of the torque curve. That extra performance comes at the price of greater heat.

In a CNC application, most of the time the cutter/material dictates that the motors run at low to moderate speed. Even when I used 3/8" cutters and MDF, I held the speed to 300 - 400 ipm. Those speeds gave me an acceptable edge finish. Going faster meant that I had to do more edge sanding. Jogging speeds were 1,200 to 1,500 ipm when I used a belt-drive.

Big motors with lots of torque can shake the machine (remember, I used a Shopbot, which used aluminum for some frame members). Flexing and shaking reduce the quality of the cut.

Your motors are rated 640 oz*in when wired half-coil. With a 3:1 belt-drive, you'll have more than enough torque (120 lb*in) to handle any job that the machine is capable of handling without breaking cutters or burning up routers/spindles.
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  #8  
Old Mon 25 April 2011, 07:57
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
(We're getting over-lapping posts, which is okay, except for the confusion it causes.)

On a Geckodrive G203v, connect one end of the current limit resistor to terminal 11 and the other end of the resistor to terminal 12. Finding an exact resistance match is not necessary. I always pick the closest standard value resistor. (There's a Radio Shack just two miles from my home where I buy a 500 piece resistor assortment for about $10. That assortment has everything I would ever need.)

The formula for finding the correct resistor is: 47 X Amps / (7 - Amps) = resistor in kilomns. So, 47 X 4.3 / (7 - 4.3) = 74.85 k
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  #9  
Old Sun 01 May 2011, 10:01
234ahmed
Just call me: Ahmed #81
 
Damietta
Egypt
Hi Phil
I have the same setup. I've tested that setup on my kitchen table project and it was perfect. I'm attaching a cad file for my arrangement and it matches your choices. Kindly consider that I have 65V transformer and i used a 51K resistor with gecko drives.
Ahmed
Attached Files
File Type: dxf my control diagram.dxf (234.5 KB, 72 views)
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