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Author Topic: Only X-axis motor is working  (Read 33568 times)

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Offline rcaffin

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Re: Only X-axis motor is working
« Reply #100 on: March 30, 2018, 01:40:02 AM »
I'm not ignoring the advice of the PS issues. I just think I should have better results (even if not perfect) than I am.
That sort of attitude will get you support from just about everyone here. Go for it!

Cheers
Roger

Offline rcaffin

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Re: Only X-axis motor is working
« Reply #101 on: March 30, 2018, 01:56:56 AM »

Offline Davek0974

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Re: Only X-axis motor is working
« Reply #102 on: March 30, 2018, 03:13:16 AM »
I think a lot of the problem might be that I hooked up my 8 wire steppers wrong.

I, mistakenly, thought I just needed 2 of the 4 coils wired and isolated the other 4 wires. It turns out I need to hook them all up either unipolar or bipolar connections.
The trick will be to find out which wires go to which coil.

These are 23LM-C304 motors. I still haven't found a color coded wiring diagram for them.

I'm not ignoring the advice of the PS issues. I just think I should have better results (even if not perfect) than I am.

Hi, been following this thread from afar...

That is a major blooper right there - with only two coils running you will certainly get poor results at low speed due to the lower momentum of the rotor - once running at speed it will overcome the missing steps, of course you will only get half or less power from them ;)

I am unsure of the PSU options here - I have three machines all running on switch mode PSU's ranging from a plasma table to a large mill with servos, all run ok. One of the leading UK suppliers recommends SM PSU's for their drives/motors as well.

However, that being said, I do have the parts for a linear PSU on hand for my plasma table as they are pretty tough on electronics and also could do with a little more voltage that SM PSU's do not offer. When you have larger motors and high acceleration settings I do think a linear PSU is good as they can give much higher surge currents faster than SM ones but with small motors/machines then easy is the way forwards I think.

Wiring your motors correctly/fully will likely fix your issues ;)
Re: Only X-axis motor is working
« Reply #103 on: March 30, 2018, 05:54:34 AM »
Hi,
having your steppers wired correctly is mandatory to get them to work properly. As you point out you need to get the best from them no matter what power supply you
use.

If you can find documentation...all well and good. If you can't then the trouble starts. There are two basic approaches you could take:
1) Using instrumentation including an oscilloscope, sinusoidal signal generator and resistance meter make measurements to work out the wiring
2) Write down all the possible combinations of wiring and using what instruments you have eliminate as many as you can and thereafter try each remaining combination to find the best
    performing combination.

Do you have electronic test gear or know someone who has and will help?

I bought a new old stock 5 phase Vexta stepper. It has 10 wires, 2 for each phase. They are electrically isolated from each other so determining the pairs of wires was easy.
There was documents that came with it and my measurements were confirmed. What the documents did not cover was the phase of each winding. I was able to determine
the phase by feeding one winding with a 1kHz sinusoid and then measuring the phase of the induced voltage in each of the other windings.

To do the same thing with a two phase stepper would be similar. Determine the 4 pairs of wires with a multimeter. Feed one winding with a sinusoid and measure the induced voltage
on each of the remaining windings. There will be one which is in tight phase (antiphase) of your input being the winding in the same slots or phase of the stepper. The remaining two windings
will be slightly less strongly coupled and will be the two windings associated with the the second phase of your two phase motor.

This process can be confusing and you will need a solid understanding of transformer action to decode the measurements you make. 'Character building'....mind you I don't have any character
and don't really want to start now!

Craig
'I enjoy sex at 73.....I live at 71 so its not too far to walk.'
Re: Only X-axis motor is working
« Reply #104 on: March 30, 2018, 10:01:21 AM »
I don't have access to an oscilloscope but have basic knowledge of how steppers work and a logical mind so this is what I am doing.

To isolate the paired wires (coils) I am bridging wires, two at a time, and spinning the motor by hand. When i feel the pulsed resistance, i know I have a coil.
Using this method I will end up with the four pairs.

Since the wires are color coded, I can, probably, deduce left and right pairs by picking the solids, and calling them right, and the stripes and calling them left.

So, I have four pairs, two left and two right.

When I bridge the two solid pairs, I have a smooth resistance. When I bridge the two striped pairs, I have smooth resistance.

So, to match the left and right I am using the same method.

First I bridge two solid wires. I have stepped resistance. If I add in pair of striped wires, bridged, I will either still have a stepped resistance or I will have a smooth resistance. If the pairs match then it's stepped resistance.

Using this method I have the paired coils.

I hooked these up in bipolar series last night and had a very smooth motor but the direction wasn't reliable. This tells me one set of coils was backwards. Just one though.
I now have a diagram written out that will help me tonight. It was too late last night to keep working on it or I would have had it ironed out then.

Stay tuned.

Offline Davek0974

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Re: Only X-axis motor is working
« Reply #105 on: March 30, 2018, 12:16:42 PM »
I think a lot of the problem might be that I hooked up my 8 wire steppers wrong.

I, mistakenly, thought I just needed 2 of the 4 coils wired and isolated the other 4 wires. It turns out I need to hook them all up either unipolar or bipolar connections.
The trick will be to find out which wires go to which coil.

These are 23LM-C304 motors. I still haven't found a color coded wiring diagram for them.

I'm not ignoring the advice of the PS issues. I just think I should have better results (even if not perfect) than I am.

Is that number correct?

Here is data for 23LM-C304 motors and it only shows 4 wire/2coil ???

http://web.archive.org/web/20050224182758/http://www.taxibooking.net/23LM-C304-51V.pdf
Re: Only X-axis motor is working
« Reply #106 on: March 30, 2018, 02:36:24 PM »
I think a lot of the problem might be that I hooked up my 8 wire steppers wrong.

I, mistakenly, thought I just needed 2 of the 4 coils wired and isolated the other 4 wires. It turns out I need to hook them all up either unipolar or bipolar connections.
The trick will be to find out which wires go to which coil.

These are 23LM-C304 motors. I still haven't found a color coded wiring diagram for them.

I'm not ignoring the advice of the PS issues. I just think I should have better results (even if not perfect) than I am.

Is that number correct?

Here is data for 23LM-C304 motors and it only shows 4 wire/2coil ???

http://web.archive.org/web/20050224182758/http://www.taxibooking.net/23LM-C304-51V.pdf
Yes, that number is correct. This seems to be an oddball one but I have over 25 of them.
Re: Only X-axis motor is working
« Reply #107 on: March 30, 2018, 08:25:36 PM »
I just found this sheet that appears to match my motors.
I need to translate it from German (I think) but the color combination looks the same.

http://www.robotikhardware.de/download/23lmc30415.pdf

Offline rcaffin

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Re: Only X-axis motor is working
« Reply #108 on: March 30, 2018, 08:34:18 PM »
Wire it up and see how it goes!
You can series the winding in each phase or parallel them.

Cheers
Roger
Re: Only X-axis motor is working
« Reply #109 on: March 30, 2018, 11:49:24 PM »
I need to find a different way to figure out the coils.

I suppose there are only a few different configurations that are possible.

I've tried in parallel. I've tried in series. Some were more fruitful than others. Some danced on my glass coffee table. Quite loudly, I might add.

I'm still not getting a smooth acceleration.

Yes, It might be the power supply. I understand that. It's just bugging me that it "shouldn't" be the power supply as this power supply went with these motors and worked great.