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  #1  
Old Fri 06 August 2010, 09:14
qroger
Just call me: Roger
 
Matthews (North Carolina)
United States of America
On to parts Ordering - Matthews NC USA

Hello all.
I have been reading and reading and reading and thinking that this might help my eventual retirement cash flow. (If I don't quit reading at work, my retirement may be sooner than originally planned!) I have started to make a list for the Kitchen Table project, trying to hold costs down. I looked at the Motion King, and the Keling, and O.M. and somehow I think I have narrowed it down to Richard-call-me-Mike's bench test setup!
4 P>K> 296 F 4.5 wired Unipolar
Gecko G-540 driver
the Avel Y236 801 Toroid with
PMDX 135-8020

I think I know that the G-540 has an onboard BOB so no need for Bob.
I feel a little guilty about taking the easy way and going for the PMDX 135-8020, but capaciters from Mouser are looking to be around $50.00. PMDX is I think $119, so $50.00 for capacitance, plus something for a Bridge and wires. I could spend as much on parts as on the 135-80, and, If I try to learn too much, too fast, I'll run out of room for the new knowledge and forget where I live.

All this looks like it could come in at around US $1000 to start. I will probably go back and look at the MotionKing Keling, Bob Campbell, etc. options but it seems what you save one place pops back up in another. For now, my plan includes belt drive reducers, so it is not the simplest approach.

All criticism, and advice will be gratefully accepted, and, as has been said many times before: THANK YOU GERALD!
roger

Last edited by qroger; Fri 06 August 2010 at 09:20..
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  #2  
Old Fri 06 August 2010, 12:41
bradm
Just call me: Brad #10
 
Somerville(MA)
United States of America
Welcome aboard, Roger!

The MK 34HS8801 might be a good choice for you, assuming that you are going with the belt drive approach.

The bridge is a $5 part with 4 connections that can be made with easily crimped connectors. You will have to wire up about 10 connections total, instead of 6 total with the PMDX. In the context of the 50 to 100 connections you need to make for the MM, it's trivial, and you are already 80% there.

Good luck, and let us know what else we can talk you in or out of
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  #3  
Old Fri 06 August 2010, 17:47
qroger
Just call me: Roger
 
Matthews (North Carolina)
United States of America
O.K., I sent a RFQ to MK for the 9801, that was recommended somewhere, and I guess I should ask about the 8801 as well. I just noticed the detent torque seems to be the difference between the two... O.M. is offering free shipping in the U.S. just to complicate things.
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  #4  
Old Sat 07 August 2010, 22:06
domino11
Just call me: Heath
 
Cornwall, Ontario
Canada
Welcome Roger!
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  #5  
Old Sun 08 August 2010, 22:27
KenC
Just call me: Ken
 
Klang
Malaysia
Welcome Roger.
If you do struggle with the budget, just start with the basic configuration.
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  #6  
Old Mon 09 August 2010, 07:03
qroger
Just call me: Roger
 
Matthews (North Carolina)
United States of America
Ken,
Thanks for the advice. It suddenly strikes me that It might be possible to begin with 4 light bulbs instead of 4 steppers! The first step would be Mach 3, plus power supply, plus drivers. Maybe with a modification that would tell if the "light bulb motors", were running forward or backwards....
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  #7  
Old Mon 09 August 2010, 16:11
MetalHead
Just call me: Mike
 
Columbiana AL
United States of America
If you are building the kitchen table project on a budget. You can just buy one motor at a time. The first motor could be used to test each axis of the system. The shipping will be rough doing it all this way, but it would allow you to spread out the costs a bit.
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  #8  
Old Mon 09 August 2010, 18:15
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
or go to a local electronics place and buy a really small stepper motor and put in a really high value resistor to current limit the drive and test for about 20 bucks. A copier machine has A LOT of really small steppers in it.
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  #9  
Old Tue 10 August 2010, 06:29
qroger
Just call me: Roger
 
Matthews (North Carolina)
United States of America
The cart before the horse

I see people in the forum that have completed the mechanical part of their table, and are then starting to choose their electric, control, and software. I Know I can build a table, (especially with the plans from Gerald and the kit from Metalhead!). Now I am banging my head on understanding the motor - driver - power supply choices. Then, I think I have to look at the software before I hit the Go button. This is very atypical for me. My usual plan is "plunge in and hope for the best". Read Read Read, Think Think Think, lol.
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  #10  
Old Tue 10 August 2010, 10:40
bolingerbe
Just call me: Bryan #54
 
Clinton(Tennessee)
United States of America
Roger,

I would not worry about the motor - driver- power supply choices. All the information is here with the people to guide you and assist along the way. This is a great project and if you do not get stressed out a very enjoyable learning experience along the way. I took my time and I am still getting the bugs out of my head to make the most of this machine when I put it to use. I use Mach 3 for the machine control software, AutoCAD to do most of the designs and V-Carve PRO to do the final work ups for depth of cut and layouts. The V-Carve PRO will generate the G-Code required to allow Mach 3 to tell your machine where to go and how deep to cut. There is a different software to allow you do the work you want with your machine and it is disused here in different areas of this forum.
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  #11  
Old Tue 10 August 2010, 12:17
qroger
Just call me: Roger
 
Matthews (North Carolina)
United States of America
Thanks all, for suggestions, messages of support, and a couple of facts have come in:
Motion King quotes34HS9801, x4 at $220.00 (total)
plus shipping $180.00 and Paypal Charge $20.00. Grand Total $420

PK 296 F4.5 comes in at $556, free shipping.

Dietech, with a motor similar to MK is at $192 plus $140.00 freight, as part of a RFQ that also quoted $232.00 for drivers.

Gecko G540 has a posted price of $299.00

A moment of panic when the G540 appeared to be inappropriate for the PK 296 F4.5, but I found the original set-up has a Current Limiting Resister, (which may also may be multi purposed as a coffee warmer). So 1.) $856 for "PK296 plus G540", 2.) $719.00 for a little adventure, Motion King plus G540, and 3.) Dietech motors and drivers $564 plus BOB, ($120.00?) $684.00 for more adventure.
4.) Keling comes in with a non gecko, everything including the PSU and BOB, for $899.00 all engineered with the adventure removed, (one hopes).
The big break is $137 between choices 1 and 2.

So 4 choices, most money/least money = about 2. Which should be diluted by further material costs... And except for the Keling package deal, the motors could be backed out for later acquisition, bringing the serious start budget to around $500.00, includes Power supply, drivers, Software, Used computer from the Evil Empire, Odds, Ends, bribe to better half, etc. Thinking of complicating my life using the Macintosh, I already own and Linux, which I know nothing about, etc. to keep my house pure.
Thanks again, back to pondering.
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  #12  
Old Tue 10 August 2010, 12:25
qroger
Just call me: Roger
 
Matthews (North Carolina)
United States of America
Quote:
Originally Posted by smreish View Post
A copier machine has A LOT of really small steppers in it.
ANNNDD there is one just down the hall that requires a rubber band to keep the door shut so it will print! It can't be too long for this world. heh heh heh.
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  #13  
Old Tue 10 August 2010, 12:45
bradm
Just call me: Brad #10
 
Somerville(MA)
United States of America
I think you want the 34HS8801, not the 34HS9901. The former is a little smaller than the latter, and may in fact be less expensive as it has less wire in it. That means a lower inductance, which means a better match for the G540. Both motors will be slightly under-driven by the G540 - and that's okay - but you might actually get more out of the smaller motor, as you aren't wasting energy on extra wire or extra mass.

You seem to have a power supply in option #4, but not in options #1-3. Add $60 to those three options.

Here's option 5:

Keling sells the G540 at $249 if you buy other items. The KL34H260-42-8A at $79 looks like it's in range when used half-coil, so $316 + $249 = $565. Add in the KL350-48 at $60 and you have a total budget of $625 + shipping.

Someone please cross check me

Last edited by bradm; Tue 10 August 2010 at 12:48.. Reason: Four motors, not three, silly me! And half-coil. Me dumb.
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  #14  
Old Tue 10 August 2010, 14:15
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
Brad,
My next MM will use that arrangement. I have been part of 3 MM builds thus far and the 4th (my personal) is going to be G540 + KL motors, belt drive. Then I will have built all variants!
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  #15  
Old Tue 10 August 2010, 14:19
qroger
Just call me: Roger
 
Matthews (North Carolina)
United States of America
Man, that seems to be getting good and without the frictional cash losses to freight.
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  #16  
Old Wed 11 August 2010, 08:55
qroger
Just call me: Roger
 
Matthews (North Carolina)
United States of America
Hmmm,
KL 34H260-42 8a says 4.2 amps unipolar Vmax 47v, 3 amp bipolar series, Vmax 82v would have to be limited to 50 for G540, right?

KL 34H280-45-8a says 4.5 amps unipolar Vmax 41v, 3.2 amp bipolar seris, Vmax 94v would have to be limited to 50 for G540, right?

Both motors look like if they are bipolar series they will fit under the G540 bar, but the Vmax is high. If they are unipolar, voltage is fine but the amps will need to be restrained. Is there a downside to using a current limiting resister, other than the heat it will probably dissipate?

Also I assumed freight on Keling would be minimal since one of their reply to addresses is "west of Chicago". I need to get RFQ out to them for freight quote while I am comparing.

Last edited by qroger; Wed 11 August 2010 at 09:03.. Reason: Make it beterer
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  #17  
Old Wed 11 August 2010, 09:50
domino11
Just call me: Heath
 
Cornwall, Ontario
Canada
Roger,
With modern stepper drivers, there is no reason for inline power resistors to limit current. The current limit is set by the driver. This is usually done with a low wattage resistor on a current setting port.
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  #18  
Old Wed 11 August 2010, 09:57
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
Roger,
if you refer to the g540 manual, pin #1 of the db9 connector allows for the current set resistor to limit the output of the drive up to 3.5 amps @ appropriate voltage not to exceed 50V.

Most steppers will be rated to work well into the 80+ DC voltage. Though, practice shows that 35 to 56v is a more common DC voltage.

I know that Brad and others have had great success with the G540. Good luck on your choices.

Sean
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  #19  
Old Wed 11 August 2010, 11:09
bradm
Just call me: Brad #10
 
Somerville(MA)
United States of America
Roger, check out these for background perspective, or even this loudmouth in an otherwise helpful thread.

You are likely going to want to run those motors (bipolar) half-coil, and don't be tempted by a larger motor. Once you understand the distinction between series, parallel, and half-coil (all bipolar), it will be easier. As Sean points out, voltage is not an absolute; any of these motors would run on 12V or lower. More voltage assists you in getting more energy into the motor, for more torque (good), and more heating (bad). For the G540, and Geckos in general, pay attention to the inductance of your chosen motor and wiring.

You're getting close, keep reading, it'll click in
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  #20  
Old Wed 11 August 2010, 14:21
qroger
Just call me: Roger
 
Matthews (North Carolina)
United States of America
Ahhhhhgggggghhhh half coil, full coil, 1 stack, 2 stack, three stack, uni polar, heh heh heh, it's making me bipolar! (the old schisophrenic, or crazy).
Thanks for your confidence. I feel I am getting closerrrrr.
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  #21  
Old Wed 11 August 2010, 21:43
qroger
Just call me: Roger
 
Matthews (North Carolina)
United States of America
*Furthermore, Unipolar motors may be used in 2 different configurations-- One, simply ignore the center taps. Two, use half the coil only by using the center tap and one of the terminals. This will produce less hold torque but allows higher top speeds because of the lower inductance.*

http://www.stepperworld.com/Tutorial...arTutorial.htm

Closer!, g'nite.
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  #22  
Old Wed 11 August 2010, 22:21
domino11
Just call me: Heath
 
Cornwall, Ontario
Canada
Roger,
Look for posts by Mike Richards, he talks about the different configurations in many threads here. Half coil would probably be the way for you to go with the G540 due to the lower voltages required. Half coil also has better low speed torque. A plus for our application.
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  #23  
Old Thu 12 August 2010, 00:08
KenC
Just call me: Ken
 
Klang
Malaysia
Roger,
Threat each phase has 2 coils, each half is an individual coil. when connected in series, they become a long coil & slender coil when connected in parallel the become a short fat coil...
Think of it as horse pulling carriage, Half coil is a single horse carriage, full coil is two horse in series with one pulling another, & parallel the coil is having 2 horses running side by side. In our application a single horse carriage is enough to get you around productively.
Once it clicks, everything will fall into their prospective. Keep reading.
If you get too frustrated, no worries, just stick to half-coil & get it running 1st.
Unless you have the means to measure the torque, speed characteristics, the bottom line is only one thing. That is as long as it work!
remember, for the motors, all those numbers you get from the formulas are just some reasonable guide lines. Don't loose hair over it if you don't get everything spot on. +/-15% are good & even 50% variance can still work you will not kill them instantly!. What you really must watch out is heat when you switch them on. If you don't, you will get smoke & fire...
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  #24  
Old Thu 12 August 2010, 07:43
qroger
Just call me: Roger
 
Matthews (North Carolina)
United States of America
Thank you all, once again. I now know what wiring 1/2 coil is and I am a little closer to choosing my configuration but... I have to go back to Gecko white paper Introduction to Steppers and find out why you wouldn't just look for a motor half as big!
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  #25  
Old Thu 12 August 2010, 07:57
KenC
Just call me: Ken
 
Klang
Malaysia
I did have the same question when I finally realise what half coil is...
There are no straight answer to it, it is a compound factor to it, one of which is the iductance of motor coils, space required to house the bigger wires to hold the current, another is the size of the rotor & stator to accomodate the chracteristics we need.
Bigger motor stops faster, smaller motor with the same performace stops slower due to elctromegnaticsm, mechanical & physical characteristics...
At the end of the day, Nema 34 is the framesize we need...

Happy learning
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  #26  
Old Thu 12 August 2010, 08:28
bradm
Just call me: Brad #10
 
Somerville(MA)
United States of America
Roger-

I think that question means you've got it! You would look for a motor 1/2 as big - except that you won't find one. The motors are manufactured to standard sizes, and generally they cram as much wire as they can into a given size to get the best performance and be competitive. Half coil is a clever tactic for getting a smaller winding in a larger frame without a fully-custom motor order.

Building on what Ken said, the MechMate design uses NEMA34 for it's physical size, in particular the 1/2" shaft that is much more robust than the NEMA23's 1/4" shaft. As it turns out, we use the smallest size NEMA34 motors, so we can't get a motor half as big without dropping down a frame size. It would probably be possible (actually I think someone did it) to use a largish, double or triple stack NEMA23 instead, but you would need different motor plates, etc.
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  #27  
Old Thu 12 August 2010, 13:07
qroger
Just call me: Roger
 
Matthews (North Carolina)
United States of America
By Jove! I think he's got it! he he he. I went back to the intro to stepper sites and I found that using 1/2 of a big motor's windings still uses all of the rotor, bigger bearings etc. The low speed current is already controlled by the driver, so the low speed power is also set by the driver. And, as you point out, just because you can identify the ideal, doesn't mean anybody makes it for you. Thanks again. Now ON TO FINDING THE MONEY!
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  #28  
Old Tue 24 August 2010, 13:57
qroger
Just call me: Roger
 
Matthews (North Carolina)
United States of America
Here is my present situation. I found a scrap metal yard that had partial reels of heavy stranded copper wire. Probably AWG #4 through #10. Had I known the wire that I will need, I would have been able to buy the wire, possibly at scrap price. I am pretty sure eventually the scrap yard will supply me most of the steel, the power supply panel, the wire, and I noticed a couple of coffins in a warehouse there.

So, now I am starting to look at the plans for wiring the kitchen table project and the control box. I may learn something. A bill of materials or recipe might tell me that I needed 3 meters of 7mm stranded wire, and after converting to a more normal measuring system, I would go to the electrical supply house, purchase the wire, and never think about it again.

It is a little like the saying of give a man a fish, and he will be without hunger for a day. Teach the man to fish, and he will never go hungry again...(Unless the factory ships come and take all of the fish out of the oceans.)
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  #29  
Old Tue 24 August 2010, 19:21
Red_boards
Just call me: Red #91
 
Melbourne
Australia
Roger,
When my motors arrived they had a nice picture that gave different wiring configurations. After comparing the pictures to ones on this site I was able to identify which I wanted (I have 8 wires from the motors, so I plumbed for bipolar parallel for optimal speed/torque). I could simply wire the correct colored wires to A; /A; B; /B - all marked on the Geckos. Easier than it looked at the outset.
My kitchen table project has a fair number of masking tape connections. But having assembled a Heath Robinson effort I'm much clearer about the connectors I need for the control box proper.
Just a note on the computer. Mach3 needs at least 1GHz clock speed. My 640 MHz machine just falls over, so I have to upgrade.
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  #30  
Old Wed 25 August 2010, 07:51
qroger
Just call me: Roger
 
Matthews (North Carolina)
United States of America
Hey Red!

Thanks for the note. I was figgering on working the comp specs back from the Mach 3 recs. He reccs 1.0ghz single core chip, 512 ram, separate Video Card w/ 32 mb ram, and a recent flavor of Windows. Up to now I have managed to keep wintel out of my house, but it's probably easier than learning how to get linux onto a Mac, then EMC to function there, then get that to talk to yet to be built cnc router.

It's funny, at work after upgrading from a single core box to a dual core box, my GIS software actually slowed down because the software didn't know how to talk to two cores at once.

Your Heath Robinson reference tripped me up for a second. I was wondering if you were refering to the old Heathkit tube equipment; then I found that Mr. Robinson is a close to cousin to Rube Goldberg.
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