Need Help! Serious noise issues

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  1. #1
    Member Mike F's Avatar
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    Default Serious noise issues

    Hi all,

    I posted this message on my build log here and Gerry (ger21) suggested I post it here also.

    I recently bought a 3HP water cooled spindle and a matching VFD from here. It took some time but I managed to track down some proper, three core, shielded, control cable with 4 sq mm cross section conductors. 6 metres cost me £52 GBP!!! - expensive stuff but they sent me 8 metres. At 13mm diameter, this stuff is not easy to work with and my first problem was to try and solder the cable to the connector when the solder buckets were too small for the size of conductor. Eventually managed that OK, wire up the input cable, put in a temporary, gravity feed water tank and ventured to try the spindle.

    First attempt was not good but after a couple of questions to the seller, to get some of the program data, all things looked good. The spindle whispers up to 24000rpm and there is absolutely no vibration whatsoever. I am truly impressed with this motor.

    Next thing to try was to run the machine at the same time as the spindle and this is where I ran into massive problems. On start up of the spindle, the machine motors vibrate like mad and start to take off. This also happens as the motor runs down, just before it stops. The scary thing is that this also happens when the Gecko drives are in the fault condition and no computer attached. I did not think it was possible for this to happen as I have a charge pump attached to the controller. On careful inspection, the relay on the charge pump switches on and off rapidly of its own accord during run up and run down of the spindle.

    The plug for both the controller and VFD share a dual socket in the workshop and the workshop has two ring mains. Removing the VFD plug and plugging it into another socket, at the other end of the workshop and on a different ring, improved matters but there was still some interference.

    An electronics friend of mine tried a couple of filters on both the VFD input and controller input but these made little difference also. He concluded that the noise was travelling down the ground lines and basically, getting everywhere on the mains circuitry.

    Before anyone asks, all my cables and wires to the servos, encoders and limit/home switches are shielded. The shielding on the spindle cable is also the ground.

    I am hoping that someone, looking in, can shed some light on this problem and offer a solution as I am sure I am not the only one who has had this problem.

    Cheers,

    Mike

    Similar Threads:
    Attached Thumbnails Attached Thumbnails Serious noise issues-spindle-z-1r-jpg   Serious noise issues-spindle-z-2r-jpg   Serious noise issues-spindle-z-3r-jpg   Serious noise issues-vfd-r-jpg  



  2. #2
    Community Moderator Al_The_Man's Avatar
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    Are you following good grounding practice, i.e. service ground and any machine grounds to a star point and all metal parts of the the machine and spindle frame with ground conductor?
    Are you running isolated power supplies?
    Do you have a DeskTop PC or laptop?
    If DT. PC. how and what manner of grounds are connected to the PC power supply?
    Personally I prefer to make an absolute common ground connection of ALL power supplies etc to the common ground point. i.e. nothing is isolated.
    Al.

    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.


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    Member Mike F's Avatar
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    I'm sorry Al but I am extremely electrically challenged. It is one of those areas that just passed me by during my informative years and try as I may, I just cannot get the hang of it. What I am sure of is that yours is good advice if only I could understand it I get confused between the terms 'ground' and 'earth' - I am told they are different but don't know why. As to 'star points' and 'isolated power supplies' - not a clue.

    If you were to tell me to connect A to B, C to D etc. I would have no problem.

    The computer is a PC running Mach3 only. As to the PC's ground, this is simply through the 3 pin mains connection here in the UK.

    I think the best bet would be for me to get my electronics friend to look over your reply and then I can reply to you in a more informative manner.

    Thinks? - maybe I should have made a clockwork machine

    With your perseverance and some help from my friend, I am sure this is doable - after all, there must be many hundreds of these devices running successfully all over the place. Just off to do some research on star points and isolated power supplies.

    Thanks,

    Mike



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    Community Moderator Al_The_Man's Avatar
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    Mike, I have installed many a PC based system in pretty harsh industrial environments over the years and have worked with a certain philosophy as to grounding etc. and common'ing supplies and have had no problems so far.
    Every week I see at least one post or another here mentioning spurious tripping of limit inputs etc, I would like to wager that the majority is caused because of an haphazard approach to grounding.
    Earth and ground is synonymous to me, Earth is commonly used in UK and ground in N.A. which should refer to a conductor that is actually at ground potential.
    One of my pet beefs ( of many ) is the use of the term Ground, especially by vendors of Drives and BOB units that refer to terminals as ground when they are actually common, or power supply common etc.
    Which in eventuality may or may not be grounded.
    Here is one link as a reference http://www.a-m-c.com/download/docume.../instnotes.pdf
    Rant over.
    Al.

    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.


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    Member Mike F's Avatar
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    Al, you can rant all you like because I actually understood some of that.

    I don't know if you have seen my build log or know how it has been built but the Y and Z axes are actually completely isolated from the X axis and even on the X axis, the ballscrew is not electrically connected to the X rails and frame. Do I need to electrically connect all these metal parts whether they have motors, encoders attached or not?

    Mike

    Incidentally I have been looking at EMI filters and line reactors - are these necessary? Those line reactors are sure expensive.

    Last edited by Mike F; 01-20-2009 at 05:07 PM. Reason: More info


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    Community Moderator Al_The_Man's Avatar
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    Quote Originally Posted by Mike F View Post
    Do I need to electrically connect all these metal parts whether they have motors, encoders attached or not?

    Mike

    Incidentally I have been looking at EMI filters and line reactors - are these necessary? Those line reactors are sure expensive.
    I would investigate proper grounding before going into line reactors etc.
    Also, there are simple EMI L/R/C filters that you can put on the 240v supply to the PC for e.g. made by Corcom and others.
    You should bond all metal parts of the machine, at least all that have anything electrical mounted on or to them. And take the bonding conductor back to the ground star point.
    I have some previous posts in the regard of Grounding practice.
    I will look over you build posts and get a better feel of what you have.
    Al.

    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.


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    Member Mike F's Avatar
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    A little more information:

    I tied all the metal structures to ground but it did not seem to make any difference. With Mach3 running but in Reset, the drives go haywire and the charge pump relay does a merry dance.

    I could not understand why the relay should be going berserk when, to all intents and purposes, Mach3 was not communicating with the controller. I had assumed that all the noise was coming down either the limit/home switch wiring, the servo motor wiring or the encoder wires. I disconnected the parallel port cable from the computer, tried the spindle again and - complete silence!!

    It seems to be a clue but I don't exactly know what to do about it.

    Mike



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    Community Moderator Al_The_Man's Avatar
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    You could first try this, with the PC off, meter resistance from the 5v common pins on the parallel port to earth ground, normally the PC power supply common will be grounded through MB mounting screws to the metal chassis.
    If high resistance, it means your PC supply is floating.
    If as expected, it is low resistance, take a ground conductor from here to your central ground point and try again.
    If high resistance, I would take steps to ground the PC power supply common and also the port common pins.
    Al.

    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.


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    Member Mike F's Avatar
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    Al,

    Fingers well and truly crossed, I think we have solved the problem.

    The PC's pins all checked out OK but we did find some wiring faults in the controller. I had mistakenly tied the shielding of the small power supply (giving me 5v and 12v) to the 0v of the supply giving me 40v. Also, the commons from the small supply were not referencing the same 0v as the other supply so these were then tied to the same reference as the main supply.

    At this point, the testing was very much better with the scope showing very little interference. However, the servos were still twitching and causing Mach3 to go into reset.

    My electronics friend then suggested we should try connecting the 0v from the supplies to the chassis ground. This seems to have been the final piece in the jigsaw and once this was done, there was not so much as a murmer from anything. The spindle was run up and down a number of times with no effect and the machine's axes were jogged whilst doing so also.

    I have to admit to being totally baffled by the whole electrical/electronic wizardry and am only too grateful for the help from those here and my local helpline.

    The next stage is to make permanent the grounding, try to route the spindle cable within the energy chain and to connect the VFD to Mach3. I appreciate that all the advice says I should not run the spindle cables alongside the other cabling but should I then run into difficulties again, at least I will know the cause and will be able to do something about it.

    I very nearly went down the route of buying expensive chokes, filters and reactors but, due to advice given here by Al, there was no need. Thanks Al for your assistance.

    Mike



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    Community Moderator Al_The_Man's Avatar
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    Quote Originally Posted by Mike F View Post
    My electronics friend then suggested we should try connecting the 0v from the supplies to the chassis ground. This seems to have been the final piece in the jigsaw and once this was done, there was not so much as a murmer from anything. The spindle was run up and down a number of times with no effect and the machine's axes were jogged whilst doing so also.


    The next stage is to make permanent the grounding,
    Mike
    Mike,
    I think that confirms my previous theory on the reasons for many of the spurious trips that constantly get reported here.
    I know a lot of people are averse to making all PS commons tied to a common earth point, but this goes part way to confirming it should be done.
    Thanks.
    Al.

    Last edited by Al_The_Man; 01-25-2009 at 06:12 PM.
    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.


  11. #11

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    Thats great Mike, glad you got it sorted and thanks for posting your findings which looks like an end to your problems.

    I'm sure it will help others in the future and maybe myself as I hope to use a similar setup.

    If you get time can you post a video of the spindle cutting some material.

    Thanks

    Andy



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    Member Mike F's Avatar
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    Hi Andy,

    I have a few things to sort out yet but once done, I am sure I could post a video. It will be on my build log though, not here. I still have to sort out a water tank for the cooling and I had thought of using the space in the gantry to house it. It means the tube runs will be short and the pump more effective though it will mean the gantry has to carry the extra load but I don't think that will be a problem.

    I will post the progress in my build log.

    Cheers,

    Mike



  13. #13

    Default Re: Serious noise issues

    I have the same issue, when starting the VFD (chinese 2.2kw / 220v) the steppers start twitching, sometimes I hear only a thick ..other times multiple thicks , and only at low rpm (going up, or going down) but also if I set the rpm to a low value like 1000rpm I hear the steppers thicking very often.

    All those sounds dissaper if I turn off the computyer or remove the paralel cable from the PC.

    What I didn't understood is where you have 0v ? I don;t know If I can also wire the 0v to ground to solve the problem.

    I attached a photo with the BOB and stepper drivers enclosure, I just mounted a dedicated 5v power supply as before I had powered the BOB using a USB cable from the PC, I though maybe I can solve the problem by adding a dedicated power supply .. nothing changed

    Attached Thumbnails Attached Thumbnails Serious noise issues-bob-jpg  


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    Default Re: Serious noise issues

    U must use grounded wire , for inputs to drivers , spindle .
    U need them ground to earth .
    Try to put bob in an grounded case , or u dont have in house ground to earth .



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    Member john-100's Avatar
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    Default Re: Serious noise issues

    Its not easy to follow all your wiring from the photos but
    it looks like you are using one 5V supply to power all of the breakout board
    doing so defeats the isolation the opto-isolator give you

    if thats the case and your using a desktop a PC
    either your wiring thats connected to the breakout could be acting as an aerial picking up noise from your spindle motor

    or if the screened wires like the limit switch wiring
    are grounded at the B.O.B and the machines metal work you could have formed an earth loop

    either way you could be injecting unwanted currents into the computers printerport ground (pins 18 t0 25)

    connecting the screen at both ends only works if everything is already bonded together
    very often the connectors on the chinese spindle motors don't have the earth pin connected so
    leakage currents either make the motor live or they pass into the machines body to go to the utility earth and possibly to the computer

    try powering the breakout boards circuit thats connects to the printer port from a USB port or a second 5V power supply

    use the existing 5V supply to power the other half of the breakpout board thats connected to the limit switches and the stepperdriver

    posting a copy of the breakout boards manual will help to see what you have done


    once you have solved the noise problem
    I would look at using a larger box to enclose the electronics

    your existing box is a bit too small to get good air circulation to keep the power supplies and stepper drivers cool
    heat shortens the life of electronic components

    John

    Last edited by john-100; 10-06-2016 at 09:29 AM.


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    Default Re: Serious noise issues

    Try with other paralel cable , maibe ur cable doesn't have ground .



  17. #17

    Default Re: Serious noise issues

    Quote Originally Posted by Andreiir View Post
    U must use grounded wire , for inputs to drivers , spindle .
    U need them ground to earth .
    Try to put bob in an grounded case , or u dont have in house ground to earth .
    All the devices are grounded, the green wire in the attached photo is the ground wire.

    Yesterday I removed the ON/OFF switch I had in this drivers box and mounted some external switches to power on the drivers box and the spindle, 2 different switches, also mounted a VOLT/AMP meter, and also a filter (like a large capacitor) on the VFD, the issue was still present, than I removed the second ground wire in the drivers box, the ground wire coming from the VFD joined other ground wires in the Drivers box, I changed this, now the ground wire from the VFD joins all the other grounds near the switches, the ground wire is much shorter now (10cm vs 1 meter before).

    This change solved my noise issue, there are no thicks animore, even if I tried to drive the spindle at a very low frequency, like 8Hz, before, if I had tried to run the spindle at 1000 rpm the thicking in the motors was very evident, a few thicks / second, now , when I tested the spindle at 8Hz there was no noise .. everything was ok.

    Quote Originally Posted by john-100 View Post
    Its not easy to follow all your wiring from the photos but
    it looks like you are using one 5V supply to power all of the breakout board
    doing so defeats the isolation the opto-isolator give you

    if thats the case and your using a desktop a PC
    either your wiring thats connected to the breakout could be acting as an aerial picking up noise from your spindle motor

    or if the screened wires like the limit switch wiring
    are grounded at the B.O.B and the machines metal work you could have formed an earth loop

    either way you could be injecting unwanted currents into the computers printerport ground (pins 18 t0 25)

    connecting the screen at both ends only works if everything is already bonded together
    very often the connectors on the chinese spindle motors don't have the earth pin connected so
    leakage currents either make the motor live or they pass into the machines body to go to the utility earth and possibly to the computer

    try powering the breakout boards circuit thats connects to the printer port from a USB port or a second 5V power supply

    use the existing 5V supply to power the other half of the breakpout board thats connected to the limit switches and the stepperdriver

    posting a copy of the breakout boards manual will help to see what you have done
    I didn;t know I can power the BOB with 2 differnt supplies, I will check it up
    Quote Originally Posted by john-100 View Post
    once you have solved the noise problem
    I would look at using a larger box to enclose the electronics

    your existing box is a bit too small to get good air circulation to keep the power supplies and stepper drivers cool
    heat shortens the life of electronic components

    John
    I think the air circulation is done perfectly by the 2 high speed fans, I have one fan pusing air in, the one in the bottom right (in the attached photo) and another fan sucking air out (top left), the airflow is quite high, if I stand in front of the box, at ~20cm from the fan blowing air out I feel a cold air to my knees , the drivers box is mounted under the CNC

    I had another problem which I don't know the cause but I wont talk much about it, because it was something that happen verry rarely and couldn't predict it, every 1 - 2 months one mottor stops while making a rapid move, or while I was driving manually, I don;t know if this could be noise related but I will start a new thread if it happens again, so far I tried this:
    - got a new PC
    - mounted a filter on the VFD
    - changed the location of the VFD...

    In the last month it didn't happen .. I'll see after the latest changes if it's still happening

    Thank you guys.

    Attached Thumbnails Attached Thumbnails Serious noise issues-drivers-box-jpg  


  18. #18
    Member john-100's Avatar
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    Default Re: Serious noise issues

    good to see it looks like you have solved the noise issue

    I have not found the manual for the breakout board
    so far I have only found this photo :-

    Serious noise issues-isolated-bob-jpg

    going by your photo I'm not convinced the power supplies will be cool enough

    to me the bottom of one supply is so close to the fan & air intake of the next supply its going to restrict the air intake
    only time will tell

    John



  19. #19

    Default Re: Serious noise issues

    Quote Originally Posted by john-100 View Post
    good to see it looks like you have solved the noise issue
    ....
    only time will tell

    John
    Hy again,

    so everything was fine until I moved my machine from my garage to my workshop, I wanted to move it for some time but now we finished splitting the workshop in multiple rooms, the workshop had almost all outlets for 380v machines, my cnc is 220v, I made 2 new cables and only used one phase from each 380v outlet.

    No I hear the motors thicking every few minutes, it doesn't happen anymore when the spindle is spinning at lower speeds, it also happens even if the VFD is turned off, the motor thick from time to time and also sometimes it almost stops making a weird sound (this stopping problem is a very old problem I had, but before it happen very very rarely, like once every 1 - 2 months ), now if I manually move the machines for 10 - 15 minutes I see the motor stopping once .. maybe twice, also last night I mounted a camera and recorded for about 5 - 10 minutes and got it on tape, I noticed the motor is not completely stopped, still spinning but much more slowly, you also can hear the loud sound



    This week I haven't milled anything as I tried to ind out the cause

    I changed the 220v cables with shielded cables

    I changed the parallel cable with a shielded one
    Tried to mount a 1500VA voltage regulator for the drivers box, than swapped it with a 2000VA UPS as the voltage regulator didn't helped,
    the shielding in the cables was connected to ground in the box where I have the switches that power on the spindle and the drivers box, on the other end of the cables the shielding is not wired to anything, A photo is attached.

    I also purchased a new BOB, but before mounting the new one I will try to make what John suggested, power the BOB with 2 different sources.
    UPDATE. I just did the test with 2 different power sources, the USB from the PC was connected to the main power port and the dedicated power source was connected to the J4 jumper. Still doing the motor locking thing you can see in the video above at minute 1:30 after a while

    I try to find an electrician with a device to measure the ground, my father told me that when he build the workshop they needed to have a good ground for authorization, it needed to be less than one, he said it was 0.6 after inserting 5 or 6 rods in the earth. If i'll find one electrician with that device I will know if the problem is because of the ground or not.

    PS. The workshop is in the same place with the garage, just 20 meters away.

    Attached Thumbnails Attached Thumbnails Serious noise issues-img_4926-jpg   Serious noise issues-img_4934-jpg   Serious noise issues-img_4927-jpg  
    Last edited by ovisopa; 10-28-2016 at 08:24 AM.


  20. #20

    Default Re: Serious noise issues

    To be sure that there is no mechanical problem (the 4 linear bearing I have on the X axis or the ball screw nut) I removed the belt and tried to spin the motor, in less than 5 minutes it happen again, check the video bellow ( second 13 )





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