Need Help! Regarding Z Axis delta servo motor stall / overload protection


Page 1 of 2 12 LastLast
Results 1 to 20 of 25

Thread: Regarding Z Axis delta servo motor stall / overload protection

  1. #1
    Member
    Join Date
    Oct 2013
    Posts
    114
    Downloads
    0
    Uploads
    0

    Post Regarding Z Axis delta servo motor stall / overload protection

    Hi guys, my question is about a z-axis servo motor that is a 1 kW delta servo motor with a 6 kW HSD spindle.

    What occurred was that I wanted to cut 18mm mdf, but I accidentally entered 185mm, which is 18.5mm, in the final cut depth field on the Artcam program.
    and I start the machine to cut the piece, the z axis motor pushing down to achieve the 185mm cutting depth.
    The spindle collet makes contact with the mdf sheet and grinds, causing smoke to appear.
    When I am aware, I push the e-stop button, but everything said above happens first.
    My concern is that the servo drive will protect the servo motor from this type of condition when the motor is pushing itself but there is resistance.
    and also for will the vfd also protect the spindle from this when the spindle shaft is start jamming because of this type of mistakes.

    Similar Threads:


  2. #2
    Member
    Join Date
    Nov 2013
    Posts
    3736
    Downloads
    0
    Uploads
    0

    Default Re: Regarding Z Axis delta servo motor stall / overload protection

    Hi,
    I use 750W Delta B2 series servos, and yes they do protect themselves. As part of the programming you can set the maximum current, which is in effect the the same
    as a maximum torque limit. If I recall correctly the default factory setting is 100% of rated current and short term overload of 300%.

    This means that your servo has plenty boogie. Whats the bet that you bend/break/wreck the Z axis long before you stall the servo.

    Just as an example: my Z axis servo is direct connected to a 5mm pitch 32mm diameter ballscrew. The peak overload is 7.1Nm and thus if
    the Z axis is physically stopped, say a collison, the stall thrust is 8.9kN, or 890kg force. Something is likely to bend or break before the servo faults out.

    You might think well I'll back off the peak torque, I mean....it is programmable right? Yes it is and you could back off but that will degrade the acceleration
    your axis can achieve also. By-in-large you want the highest acceleration you can get for the fastest and best possible tool path following, but that also means
    potentially damaging thrust under fault conditions, one comes with the other.

    Craig



  3. #3
    Member
    Join Date
    Oct 2013
    Posts
    114
    Downloads
    0
    Uploads
    0

    Default Re: Regarding Z Axis delta servo motor stall / overload protection

    Quote Originally Posted by joeavaerage View Post
    Hi,
    I use 750W Delta B2 series servos, and yes they do protect themselves. As part of the programming you can set the maximum current, which is in effect the the same
    as a maximum torque limit. If I recall correctly the default factory setting is 100% of rated current and short term overload of 300%.

    This means that your servo has plenty boogie. Whats the bet that you bend/break/wreck the Z axis long before you stall the servo.

    Just as an example: my Z axis servo is direct connected to a 5mm pitch 32mm diameter ballscrew. The peak overload is 7.1Nm and thus if
    the Z axis is physically stopped, say a collison, the stall thrust is 8.9kN, or 890kg force. Something is likely to bend or break before the servo faults out.

    You might think well I'll back off the peak torque, I mean....it is programmable right? Yes it is and you could back off but that will degrade the acceleration
    your axis can achieve also. By-in-large you want the highest acceleration you can get for the fastest and best possible tool path following, but that also means
    potentially damaging thrust under fault conditions, one comes with the other.

    Craig
    I appreciate your response, friend.

    Did you want to say that the drive's protection makes the servo motor fine? Additionally, this machine includes thick ball screws.
    You give an example, but it seems a little technical to me; could you kindly explain in plain



  4. #4
    Member
    Join Date
    Nov 2013
    Posts
    3736
    Downloads
    0
    Uploads
    0

    Default Re: Regarding Z Axis delta servo motor stall / overload protection

    Hi,
    the bottom line is that the servo is (electrically) well protected but the stall force that the servo can apply is likely to break your machine, the servo will almost certainly
    survive but its likely to bend or break something else.

    My machine can happily push nearly a ton in a fault situation before the servo trips out.

    Craig



  5. #5
    Member
    Join Date
    Jan 2013
    Location
    england
    Posts
    474
    Downloads
    0
    Uploads
    0

    Default

    Quote Originally Posted by M.Abid View Post
    Hi guys, my question is about a z-axis servo motor that is a 1 kW delta servo motor with a 6 kW HSD spindle.

    What occurred was that I wanted to cut 18mm mdf, but I accidentally entered 185mm, which is 18.5mm, in the final cut depth field on the Artcam program.
    and I start the machine to cut the piece, the z axis motor pushing down to achieve the 185mm cutting depth.
    The spindle collet makes contact with the mdf sheet and grinds, causing smoke to appear.
    When I am aware, I push the e-stop button, but everything said above happens first.
    My concern is that the servo drive will protect the servo motor from this type of condition when the motor is pushing itself but there is resistance.
    and also for will the vfd also protect the spindle from this when the spindle shaft is start jamming because of this type of mistakes.
    The drives will normally protect themselves from overcurrent in this case. However, the mechanical parts may be damaged. Machine geometry or even the spindle bearings.

    Back out of the "collision" and check the machine function and accuracy.



  6. #6
    Member
    Join Date
    Oct 2013
    Posts
    114
    Downloads
    0
    Uploads
    0

    Default Re: Regarding Z Axis delta servo motor stall / overload protection

    Quote Originally Posted by joeavaerage View Post
    Hi,
    the bottom line is that the servo is (electrically) well protected but the stall force that the servo can apply is likely to break your machine, the servo will almost certainly
    survive but its likely to bend or break something else.

    My machine can happily push nearly a ton in a fault situation before the servo trips out.

    Craig
    True, I forgot to mention that before pressing the e-stop button, I noticed that the z axis was not moving upward after jogging the z axis before pressing the e-stop button, so I restarted.
    the machine, but the z axis still does not move and does not come out after a second restart of the z moving upward. Will this indicate that the drive tripped and trigger fault code.

    Another thought was that the machine's maker might take the type of scenario into account and reduce the specifications to save the machine.

    Currently, nothing that can be seen on the machine appears to be damaged, and there is any way to tell if the ball screw is bent or not.



  7. #7
    Member
    Join Date
    Nov 2013
    Posts
    3736
    Downloads
    0
    Uploads
    0

    Default Re: Regarding Z Axis delta servo motor stall / overload protection

    Hi,
    if there is a fault of that description then open the cabinet and look at the Z axis servo drive, if its faulted it will
    have something like
    "ALM 08" or "ALM 09" or something like that.

    If I'm not mistaken current overload alarms of that type are latched, that is to say the drive MUST be reset before normal operation can resume.
    It maybe the machine maker has provided a button or other control to do this. If not you will have the turn the power off to the machine, wait 30 seconds or
    so and then repower. A power cycle resets the servo drive.

    Craig



  8. #8
    Member
    Join Date
    Oct 2013
    Posts
    114
    Downloads
    0
    Uploads
    0

    Default Re: Regarding Z Axis delta servo motor stall / overload protection

    Quote Originally Posted by servtech View Post
    The drives will normally protect themselves from overcurrent in this case. However, the mechanical parts may be damaged. Machine geometry or even the spindle bearings.

    Back out of the "collision" and check the machine function and accuracy.
    Thanks pal.
    Some times unintentional thing happens which we don't want ever.
    The machine looks works fine nothing sound/noise noticeably different from before.



  9. #9
    Member
    Join Date
    Nov 2013
    Posts
    3736
    Downloads
    0
    Uploads
    0

    Default Re: Regarding Z Axis delta servo motor stall / overload protection

    Hi,

    Another thought was that the machine's maker might take the type of scenario into account and reduce the specifications to save the machine.
    Yes they could do that but then the Z axis wouldn't work properly.

    Imagine a car maker saying 'bad accidents only happen at over 10km an hour so we are going to build our cars to do 9.9km an hour'. Really safe just a bloody useless car!

    Craig



  10. #10
    Member
    Join Date
    Oct 2013
    Posts
    114
    Downloads
    0
    Uploads
    0

    Default Re: Regarding Z Axis delta servo motor stall / overload protection

    Quote Originally Posted by joeavaerage View Post
    Hi,
    if there is a fault of that description then open the cabinet and look at the Z axis servo drive, if its faulted it will
    have something like
    "ALM 08" or "ALM 09" or something like that.

    If I'm not mistaken current overload alarms of that type are latched, that is to say the drive MUST be reset before normal operation can resume.
    It maybe the machine maker has provided a button or other control to do this. If not you will have the turn the power off to the machine, wait 30 seconds or
    so and then repower. A power cycle resets the servo drive.

    Craig
    Yes the same thing came in my mind after turn off the machine and restarted.

    I needed to check the code and open the cabinet. But I restarted in a hurry and with a little panic.

    Will the drive's restored log include the most recent error code or alarm?



  11. #11
    Member
    Join Date
    Nov 2013
    Posts
    3736
    Downloads
    0
    Uploads
    0

    Default Re: Regarding Z Axis delta servo motor stall / overload protection

    Hi,

    Will the drive's restored log include the most recent error code or alarm?
    My Delta B2 drives store fault codes, maybe five or six of them. You just have to hope it does not send a email to your boss 'the bloody plonker crashed the machine'

    Craig



  12. #12
    Member
    Join Date
    Oct 2013
    Posts
    114
    Downloads
    0
    Uploads
    0

    Default Re: Regarding Z Axis delta servo motor stall / overload protection

    Quote Originally Posted by joeavaerage View Post
    Hi,



    My Delta B2 drives store fault codes, maybe five or six of them. You just have to hope it does not send a email to your boss 'the bloody plonker crashed the machine'

    Craig
    how to find those codes i think look in to the manual the way



  13. #13
    Member
    Join Date
    Nov 2013
    Posts
    3736
    Downloads
    0
    Uploads
    0

    Default Re: Regarding Z Axis delta servo motor stall / overload protection

    Hi,
    there are two ways to read the stored codes.

    The first and preferred method is to use the Delta set-up and tuning software. That in turn requires that you have the proper cable to plug into the IEEE1394 programming
    socket and that you have the Delta software on your PC. Thereafter you just get the drive on-line and read the parameters. Whether the machine maker left the software on the PC
    is questionable.

    The other method is to push buttons like programming a microwave. To be honest its very tedious and error prone, it more likely that you'll cock up the programming of the drive
    than finding what you want. There are hundreds of parameters in at least four pages, if you cock it up you could stop the servo altogether. How would your boss feel about that?

    Craig



  14. #14
    Member
    Join Date
    Oct 2013
    Posts
    114
    Downloads
    0
    Uploads
    0

    Default Re: Regarding Z Axis delta servo motor stall / overload protection

    Quote Originally Posted by joeavaerage View Post
    Hi,
    there are two ways to read the stored codes.

    The first and preferred method is to use the Delta set-up and tuning software. That in turn requires that you have the proper cable to plug into the IEEE1394 programming
    socket and that you have the Delta software on your PC. Thereafter you just get the drive on-line and read the parameters. Whether the machine maker left the software on the PC
    is questionable.

    The other method is to push buttons like programming a microwave. To be honest its very tedious and error prone, it more likely that you'll cock up the programming of the drive
    than finding what you want. There are hundreds of parameters in at least four pages, if you cock it up you could stop the servo altogether. How would your boss feel about that?

    Craig
    I find a link https://trakmtsupport.dozuki.com/Gui...Servo+Drives/5



  15. #15
    Member
    Join Date
    Nov 2013
    Posts
    3736
    Downloads
    0
    Uploads
    0

    Default Re: Regarding Z Axis delta servo motor stall / overload protection

    Hi,
    Yep, that's how its done if you don't have the proper comms cable and software. I would advise against it....its so easy to make a mistake and screw up some other
    critical parameter. Your call. Get your bosses approval before hand or it could bite you BAD.

    Craig



  16. #16
    Member mactec54's Avatar
    Join Date
    Jan 2005
    Location
    USA
    Posts
    15362
    Downloads
    0
    Uploads
    0

    Default Re: Regarding Z Axis delta servo motor stall / overload protection

    Quote Originally Posted by joeavaerage View Post
    Hi,
    the bottom line is that the servo is (electrically) well protected but the stall force that the servo can apply is likely to break your machine, the servo will almost certainly
    survive but its likely to bend or break something else.

    My machine can happily push nearly a ton in a fault situation before the servo trips out.

    Craig
    It won't protect against this if the servo drive is set to 300% overload, this needs to be reduced to suit the machine mechanics, so it will survive, the motor / Drive and spindle will survive, you have to protect the mechanics of the machine, by setting max overload Parameters.

    Mactec54


  17. #17
    Member
    Join Date
    Nov 2013
    Posts
    3736
    Downloads
    0
    Uploads
    0

    Default Re: Regarding Z Axis delta servo motor stall / overload protection

    Hi,
    the maximum short term overload of a Delta B2 servo is 300% of rated current, and is the factory default. You can program it to be less if you wish, but in most cases
    its left as is.

    OP dove the spindle hard down into the material by mistake, everyones done it at some stage. It usually creates a hell of a bang, and not much in the way of servo or machine programming will save
    that. Or if you do program it 'to be gentle if it crashes' then the Z axis is as slow as a wet week and likely to stall under regular cutting, not much cop.

    Craig



  18. #18
    Community Moderator RaderSidetrack's Avatar
    Join Date
    Apr 2018
    Location
    East Tennessee
    Posts
    104
    Downloads
    1
    Uploads
    0

    Default Re: Regarding Z Axis delta servo motor stall / overload protection

    OK guys, if you think comments posted by another member is wrong - incorrect - not applicable - etc, its fine to reply with what you believe to be correct. After all, this is a discussion forum.

    But what is NOT acceptable is to post insults directed at another participant in the thread!

    Expect to see posts that contain insults edited by a moderator or deleted entirely.

    And all parties should keep in mind, "What is good for the goose is good for the gander too!"

    -----------------------

    Any time members see a problem with a thread, the appropriate response is to use the "Report" button to bring the problem to attention of the Moderator team.

    On a desktop system, the "Report" button is in the 'footer' of each message, and is an exclamation mark inside a black triangle, towards the left side of the message window. On my Android phone, the Report button is to the right of the "Reply" button, and has the label of "Report post that violates forum rules to moderator".

    Everyone, please use the Report button anytime you see a problem (spam, insults, fighting, etc) with a thread. Once you have reported the problem, your job is done. Simple!

    Last edited by RaderSidetrack; 02-03-2023 at 04:23 PM. Reason: add more


  19. #19
    Community Moderator RaderSidetrack's Avatar
    Join Date
    Apr 2018
    Location
    East Tennessee
    Posts
    104
    Downloads
    1
    Uploads
    0

    Default Re: Regarding Z Axis delta servo motor stall / overload protection

    As this thread has already been disrupted, I am going to make a further "moderator" post.

    Moderators sometimes face tough choices, and whatever action they take is NOT open to public discussion in the original thread.

    "Discussing moderation" is inherently off-topic, and is not going to be tolerated. You may not agree with moderator actions, and if you want to talk about that, send a PM to one or more moderators with your comments.

    DO NOT FURTHER DERAIL A THREAD WITH COMMENTS ABOUT MODERATOR ACTIONS OR DIRECTIVES!



  20. #20
    Member
    Join Date
    Oct 2013
    Posts
    114
    Downloads
    0
    Uploads
    0

    Default Re: Regarding Z Axis delta servo motor stall / overload protection

    Quote Originally Posted by joeavaerage View Post
    Hi,



    My Delta B2 drives store fault codes, maybe five or six of them. You just have to hope it does not send a email to your boss 'the bloody plonker crashed the machine'

    Craig
    HI Pal
    I checked the code which is the recent ONE which is L0003.



Page 1 of 2 12 LastLast

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
  •  


About CNCzone.com

    We are the largest and most active discussion forum for manufacturing industry. The site is 100% free to join and use, so join today!

Follow us on


Our Brands

Regarding Z Axis delta servo motor stall / overload protection

Regarding Z Axis delta servo motor stall / overload protection