584,814 active members*
5,111 visitors online*
Register for free
Login
IndustryArena Forum > CNC Electronics > Spindles / VFD > Spindle not grounded - problem with motor - is it related ?
Page 1 of 2 12
Results 1 to 20 of 22
  1. #1
    Join Date
    Jun 2022
    Posts
    30

    Spindle not grounded - problem with motor - is it related ?

    Hello guys,
    I have a question for skilled ones in electricity since I do not understand it. I had accident and would
    like to know if it could be happen by switching spindle for ungrounded one.
    I have two spindles 2,2kw water cooled. Old one and new one. Both are casual chinese versions.
    I was not satisfied with sound of bearings of new one which I used for 1,5 year. So I
    grabbed old setup I had aside and installed it. I used it for three days without problem, but
    suddenly Motor on my Z stopped work. I measured power supply, it was ok. I tried cables from other motors,
    still same. On support they told me to send it to RMA. So I did. I was thinking about if it is somehow related
    with change of spindle. So I checked wiring, because it is old spindle from time when I started to build DIY machine
    and understand to nothing. In that time I used it for 2 years without problem. What I found out, that spindle is not grounded and also on Huanyang VFD I had not connected grounding from spindle
    to power cable and had switched grounding with negative. I add photo. So my question is:

    1. Is it possible that motor could be damaged because spindle was not grounded, or
    it should be just bad coincidence that happen in similar time ? (Spindle is connected just to VFD, not further like control board...)

    2. Can someone please check the correction of VFD connection if it is right now how I marked ? (Ignore the yellow/green cable, it is really position 3 on spindle, I do not want to do resolder it) *

    thank you

  2. #2

    Re: Spindle not grounded - problem with motor - is it related ?

    If the old one worked perfectly for two years, I guess it must be the new motor problem.
    http://cncmakers.com/cnc/controllers/CNC_Controller_System/CNC_Retrofit_Package.html

  3. #3
    Join Date
    Jan 2005
    Posts
    15362

    Re: Spindle not grounded - problem with motor - is it related ?

    Quote Originally Posted by Arche View Post
    Hello guys,
    I have a question for skilled ones in electricity since I do not understand it. I had accident and would
    like to know if it could be happen by switching spindle for ungrounded one.
    I have two spindles 2,2kw water cooled. Old one and new one. Both are casual chinese versions.
    I was not satisfied with sound of bearings of new one which I used for 1,5 year. So I
    grabbed old setup I had aside and installed it. I used it for three days without problem, but
    suddenly Motor on my Z stopped work. I measured power supply, it was ok. I tried cables from other motors,
    still same. On support they told me to send it to RMA. So I did. I was thinking about if it is somehow related
    with change of spindle. So I checked wiring, because it is old spindle from time when I started to build DIY machine
    and understand to nothing. In that time I used it for 2 years without problem. What I found out, that spindle is not grounded and also on Huanyang VFD I had not connected grounding from spindle
    to power cable and had switched grounding with negative. I add photo. So my question is:

    1. Is it possible that motor could be damaged because spindle was not grounded, or
    it should be just bad coincidence that happen in similar time ? (Spindle is connected just to VFD, not further like control board...)

    2. Can someone please check the correction of VFD connection if it is right now how I marked ? (Ignore the yellow/green cable, it is really position 3 on spindle, I do not want to do resolder it) *

    thank you
    I'm surprised that you got that much running out of it wired like you have, it is very unsafe to run these spindles without a Ground, not only will it shorten the life of the Bearings in the Spindle, but the safety factor is also very high, every Spindle needs to be check for Ground 90% of the Spindles sold, don't have the Ground connected, in China, it is called population control

    R S T are all Input Power Connections, for 3Phase / Single Phase only uses R / T plus Ground ?

    If you are using Single Phase power supply, then the correct connections are for the input power, can only be R / T and Ground so the Hot (live) wire to (R) the Neutral to (T) the Ground / Earth ? to the Ground Terminal ?

    You must use the correct wire colors, or use heat shrink tubing to change the wire color.

    With the wiring like you have it, the VFD Drive may be damaged as the Input power wiring is incorrect.

    The Spindle wiring / Cable needs to be 4 wire Shielded Cable (3) Hot / live wires (1) Ground ? Plus Shield

    Wiring of the Spindle Plug
    Pin=1=U

    Pin2=V

    Pin3=W

    Pin4=Gnd ? (Ground)
    Mactec54

  4. #4
    Join Date
    Jan 2005
    Posts
    15362

    Re: Spindle not grounded - problem with motor - is it related ?

    Quote Originally Posted by cncmakers001 View Post
    If the old one worked perfectly for two years, I guess it must be the new motor problem.


    There may be a motor problem, that is easy to check, but wiring and Safety is the first problem
    Mactec54

  5. #5
    Join Date
    Jun 2022
    Posts
    30

    Re: Spindle not grounded - problem with motor - is it related ?

    Hello mactec54,
    thank you for description and advices. I know that it is pain to look into it for
    someone who understand it. Anyway I did some corrections about wiring. I have two setups of VFD-Spindles, both are
    a little bit different brand. According to your description only one connection is matching. I add schema picture.
    The first one should be alright. The second one according to the description is wrong. Anyway both setups works, spindles
    are spinning. I am little bit confused that ground mark on second VFD is under letter R, on first schema is for phase.
    I did the connection from someones video on youtube, but dunno if he used single or three phases input and if there is some difference then.
    I use single phase input.

    So should I correct second schema with:
    T *to *R
    S *to *T
    GND to S or straight to spindle GND ?

  6. #6
    Join Date
    Jan 2013
    Posts
    474
    Quote Originally Posted by Arche View Post
    Hello mactec54,
    thank you for description and advices. I know that it is pain to look into it for
    someone who understand it. Anyway I did some corrections about wiring. I have two setups of VFD-Spindles, both are
    a little bit different brand. According to your description only one connection is matching. I add schema picture.
    The first one should be alright. The second one according to the description is wrong. Anyway both setups works, spindles
    are spinning. I am little bit confused that ground mark on second VFD is under letter R, on first schema is for phase.
    I did the connection from someones video on youtube, but dunno if he used single or three phases input and if there is some difference then.
    I use single phase input.

    So should I correct second schema with:
    T *to *R
    S *to *T
    GND to S or straight to spindle GND ?
    First up : never connect a phase to ground or neutral. It's a short and fuses will blow.

    3 phase motors are generally wired star or delta.

    Star needs a neutral and ground. RST N and Ground

    Delta needs motor ground, it doesn't need a neutral (unless switchable between star/ delta)

    A split 2 phase AC motor needs two phases and direction controlled by the drive or a starter. If you use RS,ST or RT phase connections, you only change motor polarity and direction.

    Personally, I would only connect the phases I need for the machine, I wouldn't use the third phase if not required, it could be a safety issue.

    In answer to you question, only ever connect the drive to drawing.

  7. #7
    Join Date
    Jan 2005
    Posts
    15362

    Re: Spindle not grounded - problem with motor - is it related ?

    Quote Originally Posted by Arche View Post
    Hello mactec54,
    thank you for description and advices. I know that it is pain to look into it for
    someone who understand it. Anyway I did some corrections about wiring. I have two setups of VFD-Spindles, both are
    a little bit different brand. According to your description only one connection is matching. I add schema picture.
    The first one should be alright. The second one according to the description is wrong. Anyway both setups works, spindles
    are spinning. I am little bit confused that ground mark on second VFD is under letter R, on first schema is for phase.
    I did the connection from someones video on youtube, but dunno if he used single or three phases input and if there is some difference then.
    I use single phase input.

    So should I correct second schema with:
    T *to *R
    S *to *T
    GND to S or straight to spindle GND ?
    The first diagram will work, R / T plus Ground No other connection is possible

    If you connect Ground to R you will have a dead short this is very bad

    Do not look at Videos most are incorrect

    R S T are Power connections Only, the VFD Ground is the last Terminal on the Right check if it has the Ground symbol
    Mactec54

  8. #8
    Join Date
    Jan 2005
    Posts
    15362

    Re: Spindle not grounded - problem with motor - is it related ?

    Quote Originally Posted by servtech View Post

    A split 2 phase AC motor needs two phases and direction controlled by the drive or a starter. If you use RS,ST or RT phase connections, you only change motor polarity and direction.

    Personally, I would only connect the phases I need for the machine, I wouldn't use the third phase if not required, it could be a safety issue.
    Why are you posting about 2 Phase get with the program if you don't understand what is being used don't post this Bs it is only confusing for the OP
    Mactec54

  9. #9
    Join Date
    Dec 2003
    Posts
    24216

    Re: Spindle not grounded - problem with motor - is it related ?

    Quote Originally Posted by servtech View Post
    3 phase motors are generally wired star or delta.

    Star needs a neutral and ground. RST N and Ground

    .
    Who's motors are you using where the Star connection requires a neutral???
    CNC, Mechatronics Integration and Custom Machine Design

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

  10. #10
    Join Date
    Jan 2013
    Posts
    474
    Quote Originally Posted by Al_The_Man View Post
    Who's motors are you using where the Star connection requires a neutral???
    Neutral, ground, earth: they're all effectively the same thing in a circuit.

    The U2,V2,W2 motor terminals when in star connection is basically a neutral terminal strip when each winding is tied together. On some motors this point has a neutral wire. LOOK BELOW.

    https://photos.app.goo.gl/Hq5RmTv9cUQKHnKn8

  11. #11
    Join Date
    Dec 2003
    Posts
    24216

    Re: Spindle not grounded - problem with motor - is it related ?

    Three phase Star connected Motors don’t require a neutral line because there is no need even in a Y-connected motor with a common point, because the 3ph motor is an inherently balanced load,
    i.e. each phase has the same number of windings and wire size.
    So no matter how much load is on the rotor/shaft. There is no need for a neutral because all the power that goes in one phase goes equally out the other two for all three phases.

    There should always be a Earth-GND for safety and protective purposes, but that does not require the presence of a neutral.
    If it is there, it is superfluous!
    CNC, Mechatronics Integration and Custom Machine Design

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

  12. #12
    Join Date
    Jan 2013
    Posts
    474
    Quote Originally Posted by Al_The_Man View Post
    Who's motors are you using where the Star connection requires a neutral???
    It is basic theory, not a motor by name.

    https://photos.app.goo.gl/Hq5RmTv9cUQKHnKn8

  13. #13
    Join Date
    Jan 2013
    Posts
    474
    Quote Originally Posted by mactec54 View Post
    Why are you posting about 2 Phase get with the program if you don't understand what is being used don't post this Bs it is only confusing for the OP
    There is only two phases connected to that drive he posted. I was stating motor theory.

  14. #14
    Join Date
    Jan 2013
    Posts
    474
    Quote Originally Posted by Al_The_Man View Post
    Three phase Star connected Motors don’t require a neutral line because there is no need even in a Y-connected motor with a common point, because the 3ph motor is an inherently balanced load,
    i.e. each phase has the same number of windings and wire size.
    So no matter how much load is on the rotor/shaft. There is no need for a neutral because all the power that goes in one phase goes equally out the other two for all three phases.

    There should always be a Earth-GND for safety and protective purposes, but that does not require the presence of a neutral.
    If it is there, it is superfluous!
    Really ? It wasn't superfluous at my university during my degree course ????

    https://photos.app.goo.gl/Hq5RmTv9cUQKHnKn8

  15. #15
    Join Date
    Dec 2003
    Posts
    24216

    Re: Spindle not grounded - problem with motor - is it related ?

    Quote Originally Posted by servtech View Post
    Really ? It wasn't superfluous at my university during my degree course ????

    https://photos.app.goo.gl/Hq5RmTv9cUQKHnKn8
    Just explain to me why neutral is needed and why the hundreds of thousands of motors out there are running without it.?
    CNC, Mechatronics Integration and Custom Machine Design

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

  16. #16
    Join Date
    Jan 2005
    Posts
    15362

    Re: Spindle not grounded - problem with motor - is it related ?

    Quote Originally Posted by servtech View Post
    There is only two phases connected to that drive he posted. I was stating motor theory.
    Theory does not cut it, correct posting is important

    There is no such thing as two-phase power, supply being connected to any VFD Drive

    He is using Single-phase power supply, probably 230v (1) Hot (live) / Neutral Plus Ground (Earth)
    Mactec54

  17. #17
    Join Date
    Jun 2022
    Posts
    30

    Re: Spindle not grounded - problem with motor - is it related ?

    Hello guys,
    there is so many informations I do not understand and are out of topic. What
    nobody mentioned if it is possible, when spindle was not grounded, could it be possible
    that could destroy motor on Z axis through metal frame of machine ?

    I also found original message from supplier of spindle:

    --------------------
    Dear friend,
    Connect "R" and "T" (at the invert-er) to the single phase power supply.You could also connect "R" and "S" or "S" and "T".Both ways are OK.
    If you use it with three phase input,connect the three phase power supply to "R, S T",
    and then connect the "U, V, W " to the motor 1, 2, 3(U to 1, V to 2, W to 3).
    Number 4 is for earth.You can either connect earth or not.Usually, we don't connect earth )))
    --------------------

    So no wonder that so many variation of connection worked for me.


    Anyway I add some pictures.

    1: picture symbols: So I explain it, that this left ground mark is just coincidence when someone did plastic injection
    and mirrored model with symbol from right side ? So it should not be there ?

    2. picture video: This is print screen from video, some guy did this connection, like me, so it works but it is not right and ideal ?

    3. picture VFD3: *Please check it if I did correct connection, where grounding goes directly from spindle to power cord 230V.
    * * * * * * * * * So from power cord I connect only R, T and grounding from spindle goes to earth wire.

    thank you

  18. #18
    Join Date
    Jan 2005
    Posts
    15362

    Re: Spindle not grounded - problem with motor - is it related ?

    Quote Originally Posted by Arche View Post
    Hello guys,
    there is so many informations I do not understand and are out of topic. What
    nobody mentioned if it is possible, when spindle was not grounded, could it be possible
    that could destroy motor on Z axis through metal frame of machine ?

    I also found original message from supplier of spindle:

    --------------------
    Dear friend,
    Connect "R" and "T" (at the invert-er) to the single phase power supply.You could also connect "R" and "S" or "S" and "T".Both ways are OK.
    If you use it with three phase input,connect the three phase power supply to "R, S T",
    and then connect the "U, V, W " to the motor 1, 2, 3(U to 1, V to 2, W to 3).
    Number 4 is for earth.You can either connect earth or not.Usually, we don't connect earth )))
    --------------------

    So no wonder that so many variation of connection worked for me.


    Anyway I add some pictures.

    1: picture symbols: So I explain it, that this left ground mark is just coincidence when someone did plastic injection
    and mirrored model with symbol from right side ? So it should not be there ?

    2. picture video: This is print screen from video, some guy did this connection, like me, so it works but it is not right and ideal ?

    3. picture VFD3: *Please check it if I did correct connection, where grounding goes directly from spindle to power cord 230V.
    * * * * * * * * * So from power cord I connect only R, T and grounding from spindle goes to earth wire.

    thank you
    The VFD Drive Photo has the Ground symbol next to a screw in the case that is can be a Grounding point, not the R terminal above it, is only a Power Connection

    So, with a Meter you can check the screws on the plastic case and Terminal #9 to see if the (2) screws have continuity with Terminal #9, if not then you can only use the #9 Terminal for Ground / Earth connection

    The reseller does not know the correct VFD Drive connections Input Power for your VFD Drive is R / T plus Ground / Earth, there are no other connections if you followed what he said you would have a big problem

    Both the Input Power and the Spindle Ground / Earth wire need to be connected to Terminal #9 on the VFD Drive

    If you don't understand this wiring, you should get an electrician to help
    Mactec54

  19. #19
    Join Date
    Jun 2022
    Posts
    30

    Re: Spindle not grounded - problem with motor - is it related ?

    Hello mactec54,
    I measured with multimeter and there is no continuity between terminal 9 and screws, or between screws. They are just holding this peace of
    electronic together. Electricians I know, frankly, they are just always guessing.
    According my last posted connection schema picture VFD3, is it OK like that ?

  20. #20
    Join Date
    Jan 2005
    Posts
    15362

    Re: Spindle not grounded - problem with motor - is it related ?

    Quote Originally Posted by Arche View Post
    Hello mactec54,
    I measured with multimeter and there is no continuity between terminal 9 and screws, or between screws. They are just holding this peace of
    electronic together. Electricians I know, frankly, they are just always guessing.
    According my last posted connection schema picture VFD3, is it OK like that ?
    The VFD Drive must be Grounded so your schema picture is not quite right wire as my attached photo R =Hot / live T=Neutral and Ground / Earth to the #9 Terminal

    Ok then the #9 Ground screw is what you have to use.

    no electrician should be guessing confused:

    Here is how you should be wiring your VFD Drive, for others that view this not all VFD Drives are wired the same
    Mactec54

Page 1 of 2 12

Similar Threads

  1. Spindle: all 4 pins are grounded
    By allistar in forum Spindles / VFD
    Replies: 11
    Last Post: 10-23-2021, 03:28 PM
  2. Spindle rotor (& tool holder) not grounded (???)
    By dwg123 in forum Spindles / VFD
    Replies: 17
    Last Post: 07-04-2020, 01:13 AM
  3. electrical problem with stepper motor and ac spindle motor
    By pdsherathia in forum Stepper Motors / Drives
    Replies: 2
    Last Post: 01-31-2015, 07:19 PM
  4. Replies: 0
    Last Post: 08-26-2013, 05:41 PM
  5. A question of bearings - Spindle related
    By Matt Ribble in forum Linear and Rotary Motion
    Replies: 12
    Last Post: 02-25-2013, 06:10 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •