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  #61  
Old Wed 05 October 2011, 21:34
MetalHead
Just call me: Mike
 
Columbiana AL
United States of America
Current Limit Resistors - Search that and also read the 203V Manual.

270K should cover BiPollar Parallel config
Attached Images
File Type: jpg CFR-12JR-270K.jpg (16.3 KB, 580 views)
Attached Files
File Type: pdf resistor-card.pdf (126.9 KB, 32 views)
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  #62  
Old Thu 06 October 2011, 09:09
JasonC
Just call me: Jason
 
Soldotna,AK
United States of America
Thanks, I recap tonight everything.

Thanks
Jason
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  #63  
Old Thu 06 October 2011, 21:43
JasonC
Just call me: Jason
 
Soldotna,AK
United States of America
Recap

Hello,

This is what I have going so far on the electrical side.

Antek PS-5n48r12(wired 220v) = 48V, 10.5a
PMDX 126(220v)
PMDX 133 daisy chained to G203V Geckos.
Keling Tech motors KL34H280-45-8A wired Bipolar parellel

Now the questions start....I would need a 430K resistor to get to 6.3amps?

And is my supply to low...looks more like a 20 amp power sup would be better.

a 270K would be too low.?.

Searching this forum isnt helping much

Tug on my rope...lost again.
Jas
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  #64  
Old Thu 06 October 2011, 21:57
JasonC
Just call me: Jason
 
Soldotna,AK
United States of America
and a 3:1 reduction

ooppps
Jas
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  #65  
Old Thu 06 October 2011, 22:30
KenC
Just call me: Ken
 
Klang
Malaysia
I don't use Gecko stuff, so no help in that, but do you really need 6.3A ? Especially with a 3:1 reduction.
From what I see here & what I have, for most cases(Unless you pack up lots of extra weight on the car... ), 3A is ample to move things around. Disregard of the power supply voltage. . If I remember correctly, no one actually use 4A or above... please correct me if I've mistaken.

BTW, my car is heavier then most because of my Z-axis mechanism.

Instead of loosing hair over the 6.5A set up, You can start tuning with 3A limit then move up if it is not adequate; It is better for your electronics' longevity & your insomnia problem

Edit: I assume you are talking about setting current limit of the individual drivers.
If you question your overall current requirements, your 48V 10.4A is 504 VA which is more than the de-facto 300VA transformer.

Last edited by KenC; Thu 06 October 2011 at 22:39..
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  #66  
Old Thu 06 October 2011, 22:51
JasonC
Just call me: Jason
 
Soldotna,AK
United States of America
Thank you, explanations help allot.

...links to confused peoples to links to more compounded confusion to links just confuse me more, reminds me of a teacher I had and I asked how to spell something and her reply was always "look it up". I hated that teacher..lol

Jas
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  #67  
Old Fri 07 October 2011, 01:42
KenC
Just call me: Ken
 
Klang
Malaysia
This forum do not advocate spoon feeding, you need to look up before asking meaningful questions (which you did)...
Teachers can be too busy at times too
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  #68  
Old Fri 07 October 2011, 06:22
MetalHead
Just call me: Mike
 
Columbiana AL
United States of America
Your PS is plenty based on how the motors run in the machine. Go to the main forum page and look in the chapters if your having trouble getting the searches to give you info. Read the stickies in each chapter.

http://www.mechmate.com/forums/index.php

Also look at the top of the 203V Gecko. The max resistor before not using one at all is 270K. Also keep in mind this is a current limit resistor for the Gecko Drive and not for the power supply.
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  #69  
Old Fri 07 October 2011, 07:39
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
Many people are confused about the current limit resistors used on the G203v. The formula to find the correct resistance is: 47 X Amps / (7 - Amps) = resistor (in thousands), so 47 X 6.3 / (7 - 6.3) = 423K. 6.1A needs a 318K resistor and 6A needs a 282K resistor. As you approach 7A, the resistance goes up quickly.

I would use the closest standard resistor to 280K.
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  #70  
Old Fri 07 October 2011, 08:06
JasonC
Just call me: Jason
 
Soldotna,AK
United States of America
Thank you Richards, I actually had to go outside the forum for help:

Hello Jason,

Your motors call for 6.3 amperes when operated in parallel
mode. The G203V needs a 423K ohm resistor to set 6.3 amperes
as the coil current. The closest standard 5% value is 430K ohms
and I would recommend using a 430K ohm, 1/4 watt resistor.

The formula is 47*I/(7-I) where I is the current in amperes
and the result is resistor value in K ohms.

The power supply you have lists is significantly under sized.
The normal recommendation for a power supply is to have between
1/2 to 2/3 of the current rating of the motor be available from
the power supply. In your case this would point to a 20 ampere
supply.

Do not be afraid to run your motors at lower current. It will
produce less torque, but will not harm them. Just select a
lower value resistor.

Regards,
Steve
PMDX


Not looking for hand outs just a "clear uniform explanation". :-) I have looked through the chapter over and over, the contradiction throw me off track. Ill get there eventually.

Thank You Guys
Jas
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  #71  
Old Fri 07 October 2011, 09:08
KenC
Just call me: Ken
 
Klang
Malaysia
Power is power, Disregard of voltage or current combination,, when your motor draws 6.3A, fat 48V, you will be at 300W!!! The numbers says your PSU is grossly under-sized, but before you come to a conclusion, you need to know in reality, ALL motors including stepper motors won't pull more power then it needs to move. With stepper motor, only in static mode, i.e. not moving, the driver will churn out full current to hold the motor shaft in position.

It takes less then 3A individual motors to move & hold. I'm running at 60~65 Vdc which says below 180~200W per motor at its peak power,I even have 1/2 full current with my direct drive... more than enough to stay put like an anchor! Mind you, mine is still a direct drive which need more torque to move & stop.
I would go lower for cooler motor but 3A is the lowest setting my drivers allows...

Don't take my word for it, dig through the forum & you will see this pattern with other MMs as well.

BTW, you are not alone in such confusion, I was there once

Play it safe, set the current to 3A for a starter & move up if its absolutely necessary..

Last edited by KenC; Fri 07 October 2011 at 09:12..
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  #72  
Old Fri 07 October 2011, 09:59
MetalHead
Just call me: Mike
 
Columbiana AL
United States of America
Sent you a PM
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  #73  
Old Fri 07 October 2011, 16:31
MetalHead
Just call me: Mike
 
Columbiana AL
United States of America
I stand corrected about the resistor selection. It is covered in the 203 manual on page 3. I still believe that how this machine runs the 5N transformer is more than enough to support these motors. Also keep in mind these resistors LIMIT the current draw to the motors. So if you did go with the 270k (Or the 282K) that would limit your current to 6A, derating the motors a small amount. This of course can be adjusted for pushing the motor harder. You can also wire these motors half coil and that draw is then 4.5A per motor changing the resistor of course and also lowering the overall current draw on the power supply. That is another reason I like this motor (KL34H280-45-8A) http://www.kelinginc.net/KL34H280-45-8A.pdf Even half coil it has plenty of power to run the machine, especially if using belt drives. This motor gives a good cross section of uses as both a direct drive motor and a belt drive motor.

http://www.geckodrive.com/images/fck...V-7-MANUAL.pdf

TERMINAL 11 Current Set
Connect the current set resistor to this terminal
TERMINAL 12 Current Set
Connect the other end of the current set resistor to this terminal

This input matches the G203Vs current output to the motor windings. The G203V will accommodate motor winding currents from
0 to 7A. Use the following equation to calculate the value, (in kilo-Ohms) of the current set resistor:
R (in kilo-ohms) = 47 * I / (7 I) Use the nearest standard value 5% tolerance, 1/4W resistor for this setting.

Here are the current set resistor values for motor current in .5A increments.

Round the appropriate answer to the nearest 5%
resistor value.

a. 1A 7.8K
b. 1.5A 12.8K
c. 2A 18.8K
d. 2.5A 26.1K
e. 3A 35.25K
f. 3.5A 47K
g. 4A 62.67K
h. 4.5A 84.6K
i. 5A 117.5K
j. 5.5A 172.33K
k. 6A 282K
l. 6.5A 611K
m. 7A OPEN

OTHER CONSIDERATIONS:

HEATSINKING: The G203V needs heatsinking for current settings greater than 3 amps. The case temperature (measured on the
bottom plate) should not exceed 70 degrees C, and for best life should be kept at 50C degrees or less. Use heatsink compound
between the G203V and your heatsink.
CAUTION! Current settings above 3A without a heatsink may result in the G203V entering thermal shutdown.
AUTO CURRENT REDUCTION: The G203V reduces motor phase current to 71% of the set current value 1 second after the last
step pulse is sent. The G203V also changes to a special recirculating current mode to nearly eliminate motor heating.
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  #74  
Old Fri 07 October 2011, 16:34
MetalHead
Just call me: Mike
 
Columbiana AL
United States of America
The 4.5 A number can be explained here.

http://www.mechmate.com/forums/showt...5&postcount=24
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  #75  
Old Fri 07 October 2011, 22:22
JasonC
Just call me: Jason
 
Soldotna,AK
United States of America
Does anyone have a similar setup as Im running to know what kind of performance it has in parallel vs series vs half?

"4-wire, 6-wire and 8-wire motor may be used. If 6-wire motors are used, they may be connected in half winding or full winding.
This is equivalent to an 8-wire motor connected in parallel or series. If a motor is connected in series or full winding, the motor’s phase current rating is half of its parallel or unipolar rating. The choice depends on the high-speed performance required; a
parallel-connected motor will provide twice the power of a series-connected motor at the same power supply voltage." Gecko.

This is allot like wiring speakers in a car.

Jason
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  #76  
Old Fri 07 October 2011, 22:31
JasonC
Just call me: Jason
 
Soldotna,AK
United States of America
Parallel would produce twice the power and the power sup would need to feed X2 the power, basically it thinks it pushing 2 motors( --,++)...Where as series wiring fools the power supply into thinking its just 1 motor(- +- +)...?... And half is just half the coils being used.(2 of the 4 coils)..

Am I getting closer..lol.

Jason
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  #77  
Old Fri 07 October 2011, 22:41
JasonC
Just call me: Jason
 
Soldotna,AK
United States of America
As for the amps if I have 5 motors at full power I would need 30 and that where I think he is getting that from, just matching the numbers,not application. It may seem a little under but we will see.


Jas
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  #78  
Old Fri 07 October 2011, 23:13
MetalHead
Just call me: Mike
 
Columbiana AL
United States of America
You really cant run all motors at full power at the same time. As you change directions motors speed up or slow down. This happens all the time. And in 1 second after the last step is sent the Gecko derates the current to 71% reducing the current load even more.
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  #79  
Old Sat 08 October 2011, 00:31
KenC
Just call me: Ken
 
Klang
Malaysia
Earth calling Jason....
That happens only in the theoretical end-of-the-world scenario or Jupeter... On earth, 300VA is enough for MM.

Anyway, feel free to ultra over-size everything & anything as long as it makes you happy, the power is all yours & yours only.

Cheers
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  #80  
Old Sat 08 October 2011, 05:30
MetalHead
Just call me: Mike
 
Columbiana AL
United States of America
Well now Ken - That 5N PS is my idea . Jason is just trying to understand the power needs and (as well all go through) get his head around what the electrics are really doing. The cool thing here is to realize that math and the real world sometimes conflict.
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  #81  
Old Sat 08 October 2011, 09:15
JasonC
Just call me: Jason
 
Soldotna,AK
United States of America
Hi all.

No worries Ken, I got the full picture now. I just needed to weed through the terms and get my head around the whole picture. I work in theory then I got to reality. Also using analogies helped me, ( the similiar to a car stereo build really flipped the "I got it" switch). I think if I give my version of how things work it will help people like me get it.

KenC, from a testing stand point, have you tested the amp loads as it runs, in a working enviroment, like a hard wood or something similar where its workinhg the machine hard(kind a worst case senerio). It would help people to know what they are.

My biggest concern in all this was not to damage or fry anything or ME!

Im firing her up today..kitchen table style.

Thanks guy
Jason
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  #82  
Old Sat 08 October 2011, 14:01
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Jason, see this thread

Transformer supply current versus Gecko output current . . . . .

the measured real life currents are very low, and in that thread you can see we even doubted the accuracy of the ammeters in the beginning. But experience has proved over and over that the theory and formulae give oversized power supplies. The ammeters were not faulty.

No harm in having an oversized supply, unless it trips a breaker when you turn it on (some of us found that out too).
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  #83  
Old Sat 08 October 2011, 17:47
JasonC
Just call me: Jason
 
Soldotna,AK
United States of America
She alive! Green light all across the board.

Wired in the motors but no movement. Followed the mach manual but no luck so far. Tried a simple jog on the A axis and it tripped a relay in the BOB. Wires are 100% correct.

Jas
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  #84  
Old Sun 09 October 2011, 04:12
KenC
Just call me: Ken
 
Klang
Malaysia
Congrats! for the lights but most importantly weeded out the 5x oversize power tranny.

I didn't do an extensive current monitoring since Gerald already did that. My are a clamp type amp meter which is not accurate but enough to indicate there are current flowing in the cables.

During cutting, the cutting force is the other variable perimeter which contributes to the motor load. Never measure this force directly, but I said it because I realised we don't need awful lot of force to hold the work piece down during cutting. Some times it is adequate to hold the work piece down by a light press with your palm but please avoid this when you can. This is a general observation.

As for your motor, did you motors warm up after power up? Is there any exposed wires & if the exposed wires touched anything they are not suppose to?

PS, Mike, the math is correct, what went wrong is the assumption of 5 motor will draw full power at the same time.

Last edited by KenC; Sun 09 October 2011 at 04:15..
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  #85  
Old Sun 09 October 2011, 13:43
JasonC
Just call me: Jason
 
Soldotna,AK
United States of America
Thank you Ken, and no the motors did not warm up and I can turn them by hand, test button didnt move them either. I started with a 270K resistor on the first try. also I noticed that sometimes not all the J1-J6 side dont always stay on or never turn on but when I "search for new hardware" I here a click sometimes and they all light back up. I think I have a issue in the computer talking to the BOB problem. and something no set right on the other side evan though i wired it as spec requires.

Getting there though...

Jas
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  #86  
Old Sun 09 October 2011, 18:32
JasonC
Just call me: Jason
 
Soldotna,AK
United States of America
Reinstalled Mach3, working perfect now..not sure what happened to it.

Jas
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  #87  
Old Sun 09 October 2011, 19:16
JasonC
Just call me: Jason
 
Soldotna,AK
United States of America
ITS ALIVE!!!...ITS ALIVE!!!......MY CREATION IS ALIVE!!!!!!


One tuning note, only one motor hooked up -Y it goes clockwise...+Y goes clockwise.?.

Jason
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  #88  
Old Sun 09 October 2011, 20:38
JasonC
Just call me: Jason
 
Soldotna,AK
United States of America
Figure out the clockwise thing..pins and ports.

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  #89  
Old Sun 09 October 2011, 23:30
KenC
Just call me: Ken
 
Klang
Malaysia
Software are a mystery....
Congrats! Isn't it wonderful when things works!

One down, many to go.
Enjoy your journey!
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  #90  
Old Mon 10 October 2011, 04:08
MetalHead
Just call me: Mike
 
Columbiana AL
United States of America
Sweet !! Lets have a few pics and tell us what you decided on the motor wiring.
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