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IndustryArena Forum > CNC Electronics > Spindles / VFD > VFD cable too big for connector
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  1. #1
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    VFD cable too big for connector

    I have a water-cooled 1.5KW Chinese spindle with a GX16 4-pin connector that I want to connect to a Huanyang 220V VFD. I purchased a VFD cable from AutomationDirect (VFDC-16-4B-1) without first checking to make sure that it would fit. Oops. The cable diameter is much too large at about 12.7mm. I found a spec for a GX16 connector that shows a maximum cable diameter of 8.5mm. I tried machining the connector with a Dremel but it's far too small. I contacted AutomationDirect and they responded that I should swap the connector or direct-wire the motor. I'd like to swap the connector and I'm looking for an alternative that can accommodate the cable. I thought of bumping up to a larger size of GX-type connector, but the GX20 shows a max cable diameter of 9.5mm, and the GX25 shows a max of 11.5mm, so it looks like I'd have to go all the way up to a GX30. Alternatively, I could switch to a different type of connector. I see a widely available P20-4 "waterproof" connector that lists a "wire hole diameter" of 12.2mm, which is probably close enough. Has anyone run into this problem and swapped out the GX-type connectors with a different type, such as P-style connectors?
    Michael Hauser, LASERcrafted, Alameda, CA

  2. #2
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    Re: VFD cable too big for connector

    Quote Originally Posted by hauser View Post
    I have a water-cooled 1.5KW Chinese spindle with a GX16 4-pin connector that I want to connect to a Huanyang 220V VFD. I purchased a VFD cable from AutomationDirect (VFDC-16-4B-1) without first checking to make sure that it would fit. Oops. The cable diameter is much too large at about 12.7mm. I found a spec for a GX16 connector that shows a maximum cable diameter of 8.5mm. I tried machining the connector with a Dremel but it's far too small. I contacted AutomationDirect and they responded that I should swap the connector or direct-wire the motor. I'd like to swap the connector and I'm looking for an alternative that can accommodate the cable. I thought of bumping up to a larger size of GX-type connector, but the GX20 shows a max cable diameter of 9.5mm, and the GX25 shows a max of 11.5mm, so it looks like I'd have to go all the way up to a GX30. Alternatively, I could switch to a different type of connector. I see a widely available P20-4 "waterproof" connector that lists a "wire hole diameter" of 12.2mm, which is probably close enough. Has anyone run into this problem and swapped out the GX-type connectors with a different type, such as P-style connectors?
    You have the wrong cable for that size motor, IGUS has the best cable for these spindles you only need 18AWG for that size motor

    1.5Kw Spindle cable can be either of these ( 2 ) Cables

    CF6-07-04 ( 8.5Dia 18AWG )
    CF6-10-04 ( 9.5Dia 17AWG ) this cable would be Best, but the ( 07 ) will do the job

    2.2Kw Spindle cable

    CF6-15-04 ( 10Dia 16AWG )

    Yes direct wiring using a EMI Gland Shield Cable Restraint is the best of all, see snips
    Mactec54

  3. #3
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    Re: VFD cable too big for connector

    Thanks so much for this helpful info!
    If I go with a cable gland such as the one you referenced (e.g. Holland Shielding 4965-20-6.5), would it make sense to use the cable I already have, or do you still recommend getting the IGUS cable? I bought this VFD cable because I read that the double shield (braid and foil) helps with noise reduction. Thanks.
    Michael Hauser, LASERcrafted, Alameda, CA

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    Re: VFD cable too big for connector

    Quote Originally Posted by hauser View Post
    Thanks so much for this helpful info!
    If I go with a cable gland such as the one you referenced (e.g. Holland Shielding 4965-20-6.5), would it make sense to use the cable I already have, or do you still recommend getting the IGUS cable? I bought this VFD cable because I read that the double shield (braid and foil) helps with noise reduction. Thanks.
    Only correct installation helps with EMI noise, no amount of shielding will solve a noise problem if installed incorrectly

    Double Shielded Cable can help in some cases, but where you have a Cable that flex's it can cause trouble as the foil will crack after a short while, and be of no use at all, usually when they use foil the braid under is a course open weave, so not as good as a quality regular high-flex shielded cable

    Plus you have the problem of terminating / Grounding a Double Shield which it almost never happens and you only end up with the braid Grounded so overall a double shielded cable is no better than a quality regular Shielded Cable for an install like you are doing
    Mactec54

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    Re: VFD cable too big for connector

    Mr. mactec54 is right at some approach. I would comment a little bit. Some supplyers use marketing trick emphasizing double shield. It doesn't mean that the cable we are speaking about is bad.
    Double shield is absolutely necessary in some cases and you can't tell without detailed knowledge of situation.
    correct installation helps with EMI noise
    and sometimes "correct installation" requires the double shield.
    Pay attention to all risks listed by Mr. mactec54 - these advices arre very practical.
    I would advice to connect the wires directly without any connector. Depends on situation, of course, if it is possible.
    Check if you really need turbo quadro super gland. In my understanding, just a regular good quality proper size gland suits your needs.

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    Re: VFD cable too big for connector

    OK, thanks. If I get the thinner IGUS cable, I can just use the existing connector. That sounds like the simplest solution, even if it's somewhat less robust than a direct connection. I've already opened the motor and grounded the unconnected pin of the GX16 connector to the motor body. I was planning to connect the corresponding conductor of the VFD cable to the VFD ground and ground the cable shield to the ground busbar (leaving the shield unconnected at the motor).

    I am a hobbyist with very limited CNC experience and this machine won't see production use.
    Michael Hauser, LASERcrafted, Alameda, CA

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    Re: VFD cable too big for connector

    Quote Originally Posted by hauser View Post
    OK, thanks. If I get the thinner IGUS cable, I can just use the existing connector. That sounds like the simplest solution, even if it's somewhat less robust than a direct connection. I've already opened the motor and grounded the unconnected pin of the GX16 connector to the motor body. I was planning to connect the corresponding conductor of the VFD cable to the VFD ground and ground the cable shield to the ground busbar (leaving the shield unconnected at the motor).

    I am a hobbyist with very limited CNC experience and this machine won't see production use.
    Wiring is even more important when in a residential setting even at the Hobby level

    You may need a EMI Power Filter on the Input to the VFD Drive, but see how this goes first

    The shield must be connected at Both Ends, if using the 4 pin Plug / connector you don't have a choice on how to clamp the Shield, the cable restraint is the only choice you have for the spindle end, not ideal using the Plug you have there is no other choice

    You can not connect the shield to the Ground Bus the shield must be clamped direct to the Ground Plane ( the Metal Plate that everything is mounted on ) some snips on how to Terminate / Ground a Shield

    Twist all Power wires where you can, do not add Ground wires in the twist

    All Shield clamp mounting points ( Ground Plane ) must be free of Paint or anodizing
    Mactec54

  8. #8
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    Re: VFD cable too big for connector

    Quote Originally Posted by Algirdas View Post
    Mr. mactec54 is right at some approach. I would comment a little bit. Some supplyers use marketing trick emphasizing double shield. It doesn't mean that the cable we are speaking about is bad.
    Double shield is absolutely necessary in some cases and you can't tell without detailed knowledge of situation. and sometimes "correct installation" requires the double shield.
    Pay attention to all risks listed by Mr. mactec54 - these advices arre very practical.
    I would advice to connect the wires directly without any connector. Depends on situation, of course, if it is possible.
    Check if you really need turbo quadro super gland. In my understanding, just a regular good quality proper size gland suits your needs.
    If using a Gland for a Shielded Cable it needs to be able to Clamp the Shield this is the whole purpose of an EMI / EMC Gland, so a regular Gland Cable restraint is not suitable for a Shielded Cable
    Mactec54

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    Re: VFD cable too big for connector

    Quote Originally Posted by mactec54 View Post
    Wiring is even more important when in a residential setting even at the Hobby level

    You may need a EMI Power Filter on the Input to the VFD Drive, but see how this goes first

    The shield must be connected at Both Ends, if using the 4 pin Plug / connector you don't have a choice on how to clamp the Shield, the cable restraint is the only choice you have for the spindle end, not ideal using the Plug you have there is no other choice

    You can not connect the shield to the Ground Bus the shield must be clamped direct to the Ground Plane ( the Metal Plate that everything is mounted on ) some snips on how to Terminate / Ground a Shield

    Twist all Power wires where you can, do not add Ground wires in the twist

    All Shield clamp mounting points ( Ground Plane ) must be free of Paint or anodizing
    OK, thanks. I have read elsewhere to only ground the shield on one end to help avoid ground loops.

    Can you recommend a book or in-depth article on CNC machine wiring aimed and non-engineers?
    Michael Hauser, LASERcrafted, Alameda, CA

  10. #10

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    Re: VFD cable too big for connector

    Hi,
    There's good in-depth paper by Torchmate to understand the problem and with best practices to reduce effects of EMI, I have attached the pdf here
    In addition I like this article to understand the difference between grounding, earthing and bonding - with focus on CNC machines:
    https://www.ecmweb.com/basics/bondin...g-and-earthing

    -Terje

  11. #11
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    Re: VFD cable too big for connector

    Quote Originally Posted by hauser View Post
    OK, thanks. I have read elsewhere to only ground the shield on one end to help avoid ground loops.

    Can you recommend a book or in-depth article on CNC machine wiring aimed and non-engineers?
    That would be incorrect information, but can be the case with some low voltage electronics

    You first have to understand what a Ground loop is before making copied statements that other non educated people write or post videos about, in most cases Ground loops don't exist unless bad wiring practice's are used

    You can not create a Ground loop if Grounds and Shields are bonded correctly, every VFD Drive manufacture have in there manual how important it is to Terminate the Shields at both ends

    There is no books that cover VFD Drive and Shielded Cable Grounding installation for residential use, VFD Drives where never intended to be used in a residential power grid setting

    That is why it is even more important that the installer that is using 240v Single Phase Power Supply complies with the best posable EMC / EMI wiring practices

    For best wiring practices for Industrial installation, there are many book on the subject and written by the very people that manufacture electrical component's, there are codes that have to be meet also to be EMC compliant

    Using Single Phase Power Supply is much worse for noise when using a VFD Drive than in an industrial installation using 3 Phase Power supply

    Some more snips
    Mactec54

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    Re: VFD cable too big for connector

    Maybe I misunderstood the above comment saying "the shield must be connected at both ends" but I can tell you my vfd manual (and many other texts I've found) are very clear not to do this.
    You absolutely need to connect the ground pin at both ends (and at the spindle, the ground should be connected to the spindle body). But shields are often not connected at both ends as they are not meant to serve as a ground. The guidance I've seen and followed myself is that my IGUS cable has the shield grounded at the vfd end but is not terminated to anything on the spindle side. As per the vfd manual....

    For the record, the above screenshot seems to be in reference to "digital" systems where there is a transmitter and receiver which is a different scenario from the analog circumstance of a 3 phase power connection between a vfd and a spindle...

    Sent from my SM-G781U1 using Tapatalk

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    Re: VFD cable too big for connector

    Quote Originally Posted by Richmaple View Post
    Maybe I misunderstood the above comment saying "the shield must be connected at both ends" but I can tell you my vfd manual (and many other texts I've found) are very clear not to do this.
    You absolutely need to connect the ground pin at both ends (and at the spindle, the ground should be connected to the spindle body). But shields are often not connected at both ends as they are not meant to serve as a ground. The guidance I've seen and followed myself is that my IGUS cable has the shield grounded at the vfd end but is not terminated to anything on the spindle side. As per the vfd manual....

    For the record, the above screenshot seems to be in reference to "digital" systems where there is a transmitter and receiver which is a different scenario from the analog circumstance of a 3 phase power connection between a vfd and a spindle...

    Sent from my SM-G781U1 using Tapatalk
    Yes just showing the different shield applications

    Please post your VFD Drive specs and Manufacture as this is incorrect information no VFD Drive manufacture would say this
    Mactec54

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    Re: VFD cable too big for connector

    FMX tough drive 3hp vfd. BTW any chance you could repost your Mitsubishi pdf? I'd love to check it out but all of my pdf readers say it's corrupted...



    Sent from my SM-G781U1 using Tapatalk

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    Re: VFD cable too big for connector

    Quote Originally Posted by Richmaple View Post
    FMX tough drive 3hp vfd. BTW any chance you could repost your Mitsubishi pdf? I'd love to check it out but all of my pdf readers say it's corrupted...



    Sent from my SM-G781U1 using Tapatalk
    It is quite easy to see what you are looking at is an I/0 2 wire logic cable not a spindle to VFD Drive Cable

    Not sure why the PDF won't open for you I tried it and it opens ok

    Here are 2 snips from the PDF I posted these are not the most correct way it would be wired in practice but gives a good idea of how it should be done there are hundreds of VFD Drive examples like this all a little different but all achieve the same thing
    Mactec54

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    Re: VFD cable too big for connector

    Quote Originally Posted by Richmaple View Post
    FMX tough drive 3hp vfd. BTW any chance you could repost your Mitsubishi pdf? I'd love to check it out but all of my pdf readers say it's corrupted...



    Sent from my SM-G781U1 using Tapatalk
    It helps to understand what is correct and how to determine what you are looking at, your drive does not even have anything in the manual about Motor to VFD Drive main Shielded Cable, a lot of the low cost Chinese VFD Drives don't give all information needed to install a Drive like this

    Even though they show this for the low voltage logic they have this incorrect also, as for a single shield Termination you always Terminate at the source of the signal
    Mactec54

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    Re: VFD cable too big for connector

    Fair enough. I've seen in many places the guidance that a shield only needs connecting at one end if a system is properly grounded at both, but it's hard to know who is an expert and undoubtedly Mitsubishi called out ground at both ends in their diagram. So I'll bow out with nothing left to offer

    Sent from my SM-G781U1 using Tapatalk

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    Re: VFD cable too big for connector

    Quote Originally Posted by mactec54 View Post
    It is quite easy to see what you are looking at is an I/0 2 wire logic cable not a spindle to VFD Drive Cable

    Not sure why the PDF won't open for you I tried it and it opens ok

    Here are 2 snips from the PDF I posted these are not the most correct way it would be wired in practice but gives a good idea of how it should be done there are hundreds of VFD Drive examples like this all a little different but all achieve the same thing
    O.K. So.
    The twisted pair diagram is for control circuits, as in the 0-10v & GND connection for the speed control.
    Shield at 1 end with a twisted pair.

    The other diagram showing 3 phase and single phase wiring. The wiring going from the vfd to the motor itself shows 2 shield/ground symbols. This suggests shielding at both ends. (Expecting there to be connectors at these 2 points).

  19. #19
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    Re: VFD cable too big for connector

    Quote Originally Posted by Richmaple View Post
    Fair enough. I've seen in many places the guidance that a shield only needs connecting at one end if a system is properly grounded at both
    And that would be incorrect information for any VFD Drive installation

    An equipment Ground Connection is required by code

    A Ground wire connections is for safety, and is in no way related to a Shield or Shield cable Termination, they are ( 2 ) different Terminations and are not related, in any way

    Note the Shield Grounding in the Danfoss VFD diagram even the I/0 is Grounded at both ends and where it needs to be different on the RS-485 it is Grounded at ( 1 ) end which is to be expected for this type of signal
    Mactec54

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    Re: VFD cable too big for connector

    Quote Originally Posted by dazp1976 View Post
    O.K. So.
    The twisted pair diagram is for control circuits, as in the 0-10v & GND connection for the speed control.
    Shield at 1 end with a twisted pair.

    The other diagram showing 3 phase and single phase wiring. The wiring going from the vfd to the motor itself shows 2 shield/ground symbols. This suggests shielding at both ends. (Expecting there to be connectors at these 2 points).
    Correct this is the norm
    Mactec54

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