Induction from spindle

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This topic contains 28 replies, has 5 voices, and was last updated by  grishien 2 months, 1 week ago.

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  • #102276

    grishien
    Participant

    Hi all,

    I started seeing inductions that obviously come from spindle (happening only when spindle’s working). It’s a chinese 500W 12V DC spindle.

    Spindle’s power cable runs clear off regular wiring.

    So, during cutting operation head suddenly decides that current G1 command contains not for example Y61.0 but Y0.0 or whatever other  XYZ or number. Also, sometimes navigation to Sdcard menu shows strange symbols that disappear when I navigate out & again in there. Obviously that’s an induction noise influence.

    I have nothing grounded except dust collection hose and actually before it was operating OK. Induction started to happen recently.

    Anyone having such problems?

    #102279

    Jamie
    Participant

    How exactly is your spindle supply wired?  A single 12V supply feeding both your ramps (or whatever) and also the spindle?  Are you able to use a second supply for the spindle?

    #102280

    thesfreader
    Participant

    I had that exact same problem some time ago with the same spindle (Not sure I’ve corrected it, long time not tried). Do you use endstops ? I think endstops cables can transmit the induction spikes to the board.I’d test and twist them now that I think about it. I suppose you can also test and ensure the cables are far from each other if possible.

    #102284

    grishien
    Participant

    Jamie, it’s different power supplies for board and spindle.

    Thesfreader, from what I know about endstops (yes I have) they only act when you home. During operation they are unfunctional. As to their ability to induce – well, they theoretically can.

    Never mind guys. I disconnected laptop and operating only with LCD – everything is good now. Maybe if I reboot the laptop the problem will go… for a while… I decided to disconnect totally to be in full control of this matter.

    #102298

    Jamie
    Participant

    If it works when the laptop is disconnected then it suggests maybe something through the ground of the USB compared to ground of 12V for steppers.  A big loop could be susceptible to induction.  I wouldn’t expect the impedance to be high enough to be a problem, but I’m just an amateur in that area so who knows.

    Another thing you could try, since it’s a laptop, is disconnect the computer from power and operate on battery.  It would cut the ground loop, if that is related to the problem.  See if that makes a difference.

    #102371

    grishien
    Participant

    No I am fine with LCD. That was my initial plan to operate without laptop eventually since I am going to assemble several routers and will use laptop only for service, leveling and bug fixing.

    Thanks.

    #102853

    grishien
    Participant

    Problem did not completely go away. Once in a couple hours during the progress it catches an induction and makes a stupid move thus spoiling the work.

    Any ideas what and how to ground/earth in order to avoid this?

    Attachments:
    #102925

    grishien
    Participant

    Je-sus! Did 8 hours work. During 5 hours it made 8 such stupid moves, spoiled all the work. I just wondered how many more mistakes it will do so didn’t stop. Now, after 5 hours (3 hours left) it put straight cut across the board (wasn’t mentioned to do that) and suspended where it was. Finito.

    BTW, I have earthed spindle, Rapms, and I removed feeding wires away from endstop wires and any other wires. Nothing helped.

    Any ideas?

    #103014

    Barry
    Participant

    What else is on that circuit?  We’ve had refrigerators and microwaves do the same thing to the machines.  I also had a wonky power supply do that for a while.

    #103079

    grishien
    Participant

    If you mean what else there is in the house – everything. The machine is in the basement.

    Today I earthed steel frame of the router (upgraded from initial MPCNC legs into steel frame), and cases of both power supplies. All of them had 30 volts between earth and they gave little sparkles when touched. Well, I did it and it didn’t save from the glitch.

    I remember that when I used initial MPCNC structure and regular wires – there were no such glitches. Then I installed steel frame and used LAN cable for steppers and endstops. That was the only change. Problem started after such upgrade.

    Update. I found that metal objects placed in the vicinity of arduino box have 15-30 volts between them and earth. Removing off the box – potential decreases. Then I measured GND of arduino (actually Minus contact of power supply that goes to GND of RAMPS) and it’s 70 volts between earth. Not sure whether I need to earth that contact, is it safe at all?

    #103091

    Barry
    Participant

    That’s not right.  You have a short somewhere.  None of my machine’s frames are grounded, and I don’t think anyone else has them grounded unless they’ve been playing with plasma torches.  There’s also quite a few folks, myself included, running the steppers off cat-5/6 cables with no issues.

    #103161

    grishien
    Participant

    Not sure what you mean by short. SC is when there is either a fountain of sparkles momentarily or something stops working. In my case all is working but sometimes brains of router glitch.

    I have read that spindle makes noise for sure and that placing capacitor in parallel with spindle solves the problem. Placed one and got a SC – now I can waste one more power supply. This is total BS actually because a lot of people are doing that without problems, I just can’t get it why. Capacitor did not SC, it’s way beyond the safe margins for voltage and capacity – instead something SCed in PSU.

    Then I followed another advice by wrapping brains in aluminium foil and grounding it. Done, did not work out.

    I have no more ideas.

    PS. Forgot to mention, in addition to stupid movements, brains sometimes just hang, which is also considered a glitch (not only by me).

    #103163

    Jamie
    Participant

    Reminds me of a video I saw a while ago: https://www.youtube.com/watch?v=v1OuYg7AJjw

    Are you running long extension cords?  Multiple outlets?  Also seems related: https://www.v1engineering.com/forum/topic/z-not-homing-with-the-probe/

    It’s hard to really know what to suggest next because I don’t know the details of your wiring configuration.  At this point I think induction or EMI through the air is unlikely.  Through the wiring or perhaps originating from a cheap power supply seems more likely to me, and it’s probably worth checking the ground of your outlet is truly grounded.

    #103177

    Barry
    Participant

    Not sure what you mean by short. SC is when there is either a fountain of sparkles momentarily or something stops working. In my case all is working but sometimes brains of router glitch.

    I have read that spindle makes noise for sure and that placing capacitor in parallel with spindle solves the problem. Placed one and got a SC – now I can waste one more power supply. This is total BS actually because a lot of people are doing that without problems, I just can’t get it why. Capacitor did not SC, it’s way beyond the safe margins for voltage and capacity – instead something SCed in PSU.

    Then I followed another advice by wrapping brains in aluminium foil and grounding it. Done, did not work out.

    I have no more ideas.

    PS. Forgot to mention, in addition to stupid movements, brains sometimes just hang, which is also considered a glitch (not only by me).

    There should be no voltage between dc negative and ground.  If there is, your power supply is faulty, or there’s a short in the system somewhere else.  Can we see a picture of your wiring between the power supply and the rambo?

    #103185

    grishien
    Participant

    Reminds me of a video I saw a while ago: https://www.youtube.com/watch?v=v1OuYg7AJjw

    Are you running long extension cords? Multiple outlets? Also seems related: https://www.v1engineering.com/forum/topic/z-not-homing-with-the-probe/

    It’s hard to really know what to suggest next because I don’t know the details of your wiring configuration. At this point I think induction or EMI through the air is unlikely. Through the wiring or perhaps originating from a cheap power supply seems more likely to me, and it’s probably worth checking the ground of your outlet is truly grounded.

    I made ground myself. Hammered 1.5 meters if steel into the ground. Checked – 220 volts of potential with phase, should be ok.

    Well, wires are long indeed, like 2-3 meters the longest one I guess.

    You see, I would blame PSU too but before installation of steel base (see attachment, marked with red text) it was not happening.

    So far I had only big frame (red text on the screenshot) earthed.

    While each of pipes (green text on screenshot) had potential from 3 to 11 volts and each of them were not connected to anything. Now I have earthed them too. So not every massive/long metal detail in my MPCNC is connected and all is earthed. Plus the box is foiled and earthed. Testing further.

    Attachments:
    #103266

    Barry
    Participant

    You’re seeing voltage on the pipes?  You don’t have high tension electrical cables over you house do you?

    #103312

    grishien
    Participant

    You’re seeing voltage on the pipes? You don’t have high tension electrical cables over you house do you?

    It’s quite funny but I know for sure that voltage on metal objects (including MPCNC pipes) in that area comes from induction that is caused by arduino/RAMPS even if I wrap the brains in foil and earth it.

     

    Update. So many words written about such a thing. Solution appeared to be simple and absolutely not obvious. Bugs came from operating the process with accelerated tuning. I started the job and then went to menu “tune” and increased speed to 160%. Using the tuning I was seeking for optimal speed of bit movement. So, when I operated with acceleration I got bugs. When I increased speed of bit in gcode and stopped using acceleration from tune menu – problem disappeared.

    However, I must admit that connection to laptop worsened the case – bugs appeared more often when was connected (and being accelerated of course).

    One more suggestion. I stopped using acceleration the same time when I earthed MPCNC pipes. So not completely sure what was the healing factor. However, bugs seem to be logical (programmatic nature) and I didn’t earth pipes long time ago when there were no bugs. This all makes be believe that acceleration is the main cause.

    #103331

    Jamie
    Participant

    I made ground myself. Hammered 1.5 meters if steel into the ground. Checked – 220 volts of potential with phase, should be ok.

    This sounds like a problem. True “earth” as in the dirt beneath you is not the same as the ground (usually green) wire in your outlets. Even if the green wire connects eventually to the dirt near your house (it should), you can’t treat them the same.

    I dont know how your house is wired, (or if you even have 3-wire plugs) but you should be using the green ground wire in your outlets to ground everything. If you want to also connect that green wire to the dirt, that is fine, but the green wire is critical. That is the gist of the video I linked above.

    From what you have described, in my opinion, the ground wiring is the most likely cause of your problem.

    #103339

    grishien
    Participant

    I made ground myself. Hammered 1.5 meters if steel into the ground. Checked – 220 volts of potential with phase, should be ok.

    This sounds like a problem. True “earth” as in the dirt beneath you is not the same as the ground (usually green) wire in your outlets. Even if the green wire connects eventually to the dirt near your house (it should), you can’t treat them the same.

    I dont know how your house is wired, (or if you even have 3-wire plugs) but you should be using the green ground wire in your outlets to ground everything. If you want to also connect that green wire to the dirt, that is fine, but the green wire is critical. That is the gist of the video I linked above.

    In our country we as a rule do not have third wire. It’s just national opportunist approach in everything and everywhere including houses construction. In my case also. So I have to make ground myself and only for MPCNC usage. And my setup shows 220 volts with phase so I consider it more than enough for the purpose.

    From what you have described, in my opinion, the ground wiring is the most likely cause of your problem.

    Then why did I not have this problem when I operated 100% original MPCNC setup without my editions?

    #103341

    Jamie
    Participant

    Ok this is helpful because my assumptions were very different based on what is most common here.  I dont have the answer but I will think about what might help in your situation.

    #103355

    Barry
    Participant

    I still don’t see how the arduino/ramps is inducing any voltage into the frame.  Only alternating current, or moving dc motors can induce a current.  There’s no meaningful ac current in an arduino.  Now your power supply, that has ac, which stops at the power supply, then dc to the arduino.  So, like I said, if you’re seeing voltage on the tubes, something is electrically shorted on your frame somewhere.

    #103411

    grishien
    Participant

    I still don’t see how the arduino/ramps is inducing any voltage into the frame. Only alternating current, or moving dc motors can induce a current. There’s no meaningful ac current in an arduino. Now your power supply, that has ac, which stops at the power supply, then dc to the arduino. So, like I said, if you’re seeing voltage on the tubes, something is electrically shorted on your frame somewhere.

    Yes, I understand. But I turn on power supply only and metal plate that I put under the brains box shows near 9-10 volts AC with ground. Then I connect box and see rise to 15-20 volts. It’s strange but it happens.

    Anyways, problem that I raised in this thread is solved with two actions:

    1. Refraining from processing with accelerated speed
    2. using good SD card (chinese SD that I recevied with OEM printer was causing artefacts on display and perhaps had problems with delivering gcode into the processor)
    #103417

    Ryan
    Keymaster

    Refraining from processing with accelerated speed

    This could be from all the new acceleration options we now have. That FR adjustment has always been wonky and I believe was put in more to slow things down, in case of a bad print, than to speed them up as speeding things up used to really mess things up as it did not obey the accel’s or max speeds. I am not sure where it is at now but the new equations are very complex and there are some issues without speeding it up already (Jamie, junction deviation?).

    So good for a quick test, but I would never rely on this where money is involved, bits, material, precious time.

    using good SD card

    Agreed a bad card is annoying.

     

    I highly recommend finding the source of that stray voltage as that is bad and could potentially be dangerous. I also believe this has to do with the Spindle PS. Maybe open it up (if you are knowledgeable enough to be safe)and look for the issue but this has come up more than once as a problem source. Some are good and some are horrible.

    #103472

    grishien
    Participant

    I highly recommend finding the source of that stray voltage as that is bad and could potentially be dangerous. I also believe this has to do with the Spindle PS. Maybe open it up (if you are knowledgeable enough to be safe)and look for the issue but this has come up more than once as a problem source. Some are good and some are horrible.

    Actually that voltage on metal things in the area occurs there by air provided that one of PSs is on. And also working brains (arduino+ramps) add a few volts, I don’t know how but I witness it.

    I can’t prevent it from happening but I can ground it.

    #103479

    Jamie
    Participant

    Can you try measuring if you have voltage between your ground and your water pipes?  BE CAREFUL: there is a potential for shock.  This assumes your pipes are metal and tied into a large network, which is true for city utilities here but maybe not for you depending on your situation.

    Some (most?) switch mode power supplies can produce high voltages (at low current) onto the ground input, or PSU case if there is no third prong.  This is intentional to reduce electrical noise going back into the mains.

    It might be possible that your earth connection is not making good enough electrical contact with the earth.  If this is the case then your ground could be somewhat of a floating island.

    If these are both happening then you could have voltage between ground and the “air”, not because the “air” is inducing voltage but because the ground is.  If this were DC then it would not be a problem but with AC you will have some capacitance between different parts of your system and the “air” and then fluctuations in your ground will produce voltages within your system.  This can produce intermittent problems that create misleading symptoms as the problem comes and goes (laptop/no laptop, etc).

    You are definitely observing voltage between ground and “air” but it is unlikely that electromagnetic or electrostatic induction could cause these high voltages, so I think it is much more likely that the fluctuation is in the ground and not in the “air”.  You could try a very long wire to measure voltage from ground to a metal object far away.  I would predict that you would see similar voltage, which means it is not being induced through the air to the metal object, but that the ground is carrying the voltage.

    As for a solution, if you have a voltage between ground and your water pipes, then try using your water pipes as ground.

    If you don’t have metal water pipes then try this configuration:

    • Isolate your PSU cases from everything else
    • And do not connect the ground wires (third prong) of the PSUs (if any) to each other or to anything else
    • And do not connect DC negative of spindle and stepper supply together
    • You can still tie RAMPs ground (DC negative) to earth if you wish
    • This configuration is not safe but if you have no good ground then you are already unsafe.  This configuration can shock you if you touch PSU cases, but your existing configuration can shock you if you touch anything.

     

    #103583

    grishien
    Participant

    between your ground and your water pipes

    I don’t have water pipes. I use “heatfloor” and fireplace to warm up.

    It might be possible that your earth connection is not making good enough electrical contact with the earth. If this is the case then your ground could be somewhat of a floating island.

    No, if I ground with the ground insert that I made – then it is grounded well. I check that everytime if I do it before usage.

    electromagnetic or electrostatic induction could cause these high voltages

    Such an experiment: I measure voltage between phase and ground – stable 220V (+/-2). I put steel plate 4mm thick, 300*300 on a wooden table in the vicinity of the PSUs and arduino/ramps. I turn everything off. Measure AC Voltage between ground and plate – 0V. turn on 1 PSU, measure – 4V. Turn on one more PSU – 8-10V. Connect arduino -> 12-15V. Is it not induction through air?

    using your water pipes as ground

    That’s a dangerous advise. I saw youtube explanation why should not do it. In general may be fine but  if any device gets SC – you’re screwed.

    You can still tie RAMPs ground (DC negative) to earth if you wish

    I thought about that but wasn’t sure if that’s safe for the PCB.

    but your existing configuration can shock you if you touch anything

    On the contrary, since I grounded metal surfaces, MPCNC metal parts and cases of PSUs – I don’t feel any more sparkles when I touch something.

    #103586

    grishien
    Participant

    Here I can put some more information somehow connected to the topic.

    I had one stepper to make sporadic steps without permission. Luckily I used deductive method and found that spindle feeding wire went across the stepper’s wire. When I moved them away 10 cm apart – error disappeared.

    #103588

    Jamie
    Participant

    Such an experiment: I measure voltage between phase and ground – stable 220V (+/-2). I put steel plate 4mm thick, 300*300 on a wooden table in the vicinity of the PSUs and arduino/ramps. I turn everything off. Measure AC Voltage between ground and plate – 0V. turn on 1 PSU, measure – 4V. Turn on one more PSU – 8-10V. Connect arduino -> 12-15V. Is it not induction through air?

    If the power supplies generate stray voltages into the ground wires, it could produce a different amount depending on the load.  To prove that it is through the air from the Arduino you should move the plate far away from the Arduino and confirm that the voltage does not appear.  If it still appears, then the voltage is in your ground wires and not in the air.  If it does not appear when you move it away, then yes something is inducing through the air.

    #103692

    grishien
    Participant

    move the plate far away from the Arduino and confirm that the voltage does not appear

    Exactly. I forgot to mention it but I did it and voltage on plate disappears when away. However, brains box was still close to PSUs so I can’t tell for sure which of the devices produce the most part of impact.

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