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  1. #1

    A real bad day

    I have ran this dummy program many of times. Nothing in the spindle, just to run the machine. Partner 1 centurion5. Running on 3 phase converter I went to the house for lunch. I came back out and the shop was full of smoke. Open the console and that made a real bad day. I would like to have an opinion as to the cause.
    Attached Thumbnails Attached Thumbnails IMG_3713.jpg   IMG_3714.jpg   IMG_3715.jpg   IMG_3639.jpg  


  2. #2
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    Dec 2013
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    5717

    Re: A real bad day

    Looks like the VFD burned up, and took out the wiring to the drives.

    Normally VFDs need to be mounted vertically for proper air flow and cooling, but sometimes they just fail anyway.... Catastrophically, as seems to be the case here.

    It could be that the breaking transistor in the VFD shorted out and heated up the big resistor and that is what caused the heating of the wiring around it, but I find it odd that there is no discoloration on the resistor that would indicate overheating. Maybe it got hot enough to clean its self?
    Jim Dawson
    Sandy, Oregon, USA

  3. #3
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    Re: A real bad day

    Quote Originally Posted by Grasshopper75 View Post
    I have ran this dummy program many of times. Nothing in the spindle, just to run the machine. Partner 1 centurion5. Running on 3 phase converter I went to the house for lunch. I came back out and the shop was full of smoke. Open the console and that made a real bad day. I would like to have an opinion as to the cause.
    The RPC converters are good at doing this to CNC Machines, over time they will kill the Drives, and any sensitive electronics.
    Mactec54

  4. #4
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    Re: A real bad day

    Quote Originally Posted by Jim Dawson View Post
    Looks like the VFD burned up, and took out the wiring to the drives.

    Normally VFDs need to be mounted vertically for proper air flow and cooling, but sometimes they just fail anyway.... Catastrophically, as seems to be the case here.

    It could be that the breaking transistor in the VFD shorted out and heated up the big resistor and that is what caused the heating of the wiring around it, but I find it odd that there is no discoloration on the resistor that would indicate overheating. Maybe it got hot enough to clean its self?
    The Braking Resistor is not doing anything if the spindle was running, that only acts when the spindle is stopping and would not cause this burn up

    The RPC caused this burn up with over voltage, seen the same thing many times.

    The VFD is mounted in it's normal position, cooling is not a problem, this did not over heat, if it did it would of shut down.
    Mactec54

  5. #5
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    Re: A real bad day

    Quote Originally Posted by Grasshopper75 View Post
    I have ran this dummy program many of times. Nothing in the spindle, just to run the machine. Partner 1 centurion5. Running on 3 phase converter I went to the house for lunch. I came back out and the shop was full of smoke. Open the console and that made a real bad day. I would like to have an opinion as to the cause.
    Why where you using a RPC for this mill, it looks like your spindle HP is only 5Hp, you could of been running this machine on 240v Single Phase and this would not of happened.
    Mactec54

  6. #6
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    Re: A real bad day

    Quote Originally Posted by mactec54 View Post
    The Braking Resistor is not doing anything if the spindle was running, that only acts when the spindle is stopping and would not cause this burn up

    The RPC caused this burn up with over voltage, seen the same thing many times.

    The VFD is mounted in it's normal position, cooling is not a problem, this did not over heat, if it did it would of shut down.
    If the chopper transistor failed closed (shorted) it would dump power to the breaking resistor.

    Over voltage? Maybe.

    That VFD is laying on its back in the bottom of the cabinet by the looks of the pictures. That is not the way to install a VFD.

    It took some time to char the control wiring for the drives and that other wire bundle in the corner. That didn't happen instantly from a single flash out of the drive.
    Jim Dawson
    Sandy, Oregon, USA

  7. #7
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    Re: A real bad day

    Quote Originally Posted by Jim Dawson View Post
    If the chopper transistor failed closed (shorted) it would dump power to the breaking resistor.

    Over voltage? Maybe.

    That VFD is laying on its back in the bottom of the cabinet by the looks of the pictures. That is not the way to install a VFD.

    It took some time to char the control wiring for the drives and that other wire bundle in the corner. That didn't happen instantly from a single flash out of the drive.
    If the chopper circuit failed it would only heat up the Braking Resistor it would not burn anything up like this. everything was fried from over voltage.

    Jim there are no connection between the VFD drive circuits, and the Servo Drive circuits. but all where fried, there should be no confusion as to what happened. if there is a Transformer feeding the axis Drives, that also failed and feed line voltage to the Axis Drives cards.

    The VFD drive is mounted with screws, in the bottom of the cabinet, ( Not sure what you are looking at ) which is normal for these machines, it is not laying on it's side.

    Need to see more photos
    Mactec54

  8. #8
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    Re: A real bad day

    Quote Originally Posted by mactec54 View Post
    If the chopper circuit failed it would only heat up the Braking Resistor it would not burn anything up like this. everything was fried from over voltage.

    Jim there are no connection between the VFD drive circuits, and the Servo Drive circuits. but all where fried, there should be no confusion as to what happened. if there is a Transformer feeding the axis Drives, that also failed and feed line voltage to the Axis Drives cards.

    The VFD drive is mounted with screws, in the bottom of the cabinet, ( Not sure what you are looking at ) which is normal for these machines, it is not laying on it's side.

    Need to see more photos

    You might spend some time studying the pictures of the wiring and cabinet immediately around the breaking resistor, and look for the obvious signs of extend high temperatures in that immediate area.

    There is not enough power available for the drives' control circuits to heat those 16ga wires like that. Drive power, yes Control circuits, no.
    Jim Dawson
    Sandy, Oregon, USA

  9. #9
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    Re: A real bad day

    it has to be co\/1d just kidding ...
    Ladyhawke - My Delirium, https://www.youtube.com/watch?v=X_bFO1SNRZg

  10. #10
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    Re: A real bad day

    Quote Originally Posted by Jim Dawson View Post
    You might spend some time studying the pictures of the wiring and cabinet immediately around the breaking resistor, and look for the obvious signs of extend high temperatures in that immediate area.

    There is not enough power available for the drives' control circuits to heat those 16ga wires like that. Drive power, yes Control circuits, no.
    There is if the low voltage Transformer failed also, and supplied full line voltage, need more photos to know for sure, but what ever it was there was a lot of heat, a lot more than what you can get from just the Braking Resistor, which seems to be mounted in a strange place.
    Mactec54

  11. #11

    Re: A real bad day

    Thanks to all! I will get more pictures of the console, before this happened. The program has a tool change in the middle of the program. I am not an electronics person, just a toolmaker. I build injection molds. I have a inverter coming, I will have a tech help me through this, can't give up.
    I really don't understand your acronyms. Today prep, tomorrow colonoscopy yea.

  12. #12
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    Re: A real bad day

    Quote Originally Posted by Grasshopper75 View Post
    Thanks to all! I will get more pictures of the console, before this happened. The program has a tool change in the middle of the program. I am not an electronics person, just a toolmaker. I build injection molds. I have a inverter coming, I will have a tech help me through this, can't give up.
    I really don't understand your acronyms. Today prep, tomorrow colonoscopy yea.
    Then do away with the Rotary Phase Converter, it is not hard to wire this machine to run direct on 240v Single Phase supply, hope there is not too much damage.
    Mactec54

  13. #13

    Re: A real bad day

    mactec54, the machine is 7.5hp.? Here are some more pictures. I really would not like to fix the machine, without knowing why. The machine was running fine, until now.
    Attached Thumbnails Attached Thumbnails IMG_3731.jpg   inverter-1.jpg   inverter-2.jpg   IMG_3730.jpg  

    IMG_3733.jpg   what is this.jpg   glentek drive board.jpg  

  14. #14
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    Re: A real bad day

    After looking at the new pictures, it still seems that the heat was concentrated in two areas. 1) around the breaking resistor and 2) inside the VFD. In the wide shot of the panel, there seems to be a hot spot in the wire bundle, center, in the lower 1/3 of the picture also, but I cant really tell. The secondary fuse (glass fuse) on the transformer seems to be intact which would indicate no over current on that circuit.

    It also looks like the resistor, R50, on the Glentek board has been hot at some time in its life, this may or may not have happened during this incident. It's hard to tell from the pictures, but it looks like the only damage to the drive control wire bundles is that the cover sheath is burned off with perhaps no damage to the actual wires, again, it's hard to see in the pictures.

    It's my opinion that the breaking chopper transistor in the drive failed (shorted) and dumped power to the breaking resistor, thus causing it to heat up to the point of destruction of the local wiring. The damage around the VFD internal large resistors support that conclusion.

    Was the root cause an over voltage condition caused by extended operation on an unbalanced RPC as mactec45 suggests? I don't know. Without knowing what the loaded voltage output of the RPC was, it's hard to say. It could be that the VFD was just old and finally just died of old age.

    For a fix, I would install a new VFD, replace damaged wiring as needed, fire up the machine and see what happens. You won't really know if the Glentek drives are damaged until you try to run them. The VFD needs to be replaced in any case, so buying a new one is not wasted money even if the Glentek drives are damaged.
    Jim Dawson
    Sandy, Oregon, USA

  15. #15
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    Re: A real bad day

    Quote Originally Posted by Jim Dawson View Post
    After looking at the new pictures, it still seems that the heat was concentrated in two areas. 1) around the breaking resistor and 2) inside the VFD. In the wide shot of the panel, there seems to be a hot spot in the wire bundle, center, in the lower 1/3 of the picture also, but I cant really tell. The secondary fuse (glass fuse) on the transformer seems to be intact which would indicate no over current on that circuit.

    It also looks like the resistor, R50, on the Glentek board has been hot at some time in its life, this may or may not have happened during this incident. It's hard to tell from the pictures, but it looks like the only damage to the drive control wire bundles is that the cover sheath is burned off with perhaps no damage to the actual wires, again, it's hard to see in the pictures.

    It's my opinion that the breaking chopper transistor in the drive failed (shorted) and dumped power to the breaking resistor, thus causing it to heat up to the point of destruction of the local wiring. The damage around the VFD internal large resistors support that conclusion.

    Was the root cause an over voltage condition caused by extended operation on an unbalanced RPC as mactec45 suggests? I don't know. Without knowing what the loaded voltage output of the RPC was, it's hard to say. It could be that the VFD was just old and finally just died of old age.

    For a fix, I would install a new VFD, replace damaged wiring as needed, fire up the machine and see what happens. You won't really know if the Glentek drives are damaged until you try to run them. The VFD needs to be replaced in any case, so buying a new one is not wasted money even if the Glentek drives are damaged.
    I agree after seeing this lot of photo's, the VFD Drive failed and everything else got cooked, there was an over voltage to cause this though, so I would set the machine up to run on 240v single phase and not use the RPC for this machine.
    Mactec54

  16. #16
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    Re: A real bad day

    Quote Originally Posted by Grasshopper75 View Post
    mactec54, the machine is 7.5hp.? Here are some more pictures. I really would not like to fix the machine, without knowing why. The machine was running fine, until now.
    Not by the VFD Drive number that is a 5Hp VFD Drive, if your spindle motor is 7.5 Hp then the VFD Drive is way to small for that motor size.

    Even if it is you could still run it on 240v single Phase supply.
    Attached Thumbnails Attached Thumbnails VFD 23P7.PNG  
    Mactec54

  17. #17
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    Re: A real bad day

    ...the ground wire. looks like it did its job, what failed was a breaker/fuse antlog logic link do sences/stop the short to ground.

  18. #18
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    Re: A real bad day

    Quote Originally Posted by mactec54 View Post
    Not by the VFD Drive number that is a 5Hp VFD Drive, if your spindle motor is 7.5 Hp then the VFD Drive is way to small for that motor size.
    Even if it is you could still run it on 240v single Phase supply.
    Overloaded vfd and an unlucky safety failure perhaps?.

  19. #19

    Re: A real bad day

    Than you all. I pulled the cover on the spindle motor and it is 7.5 hp. I took pictures of the new VFD drive. It is the copy of the old one. That has me scared of the 7.5hp. If I may ask what is RDC and breaking resistor and where are they at. Rest assured I will have an Milltronics tech install after I get all the parts. I did pull all the XYZ drive boards and they look fried. I am also sending a picture of the 240 volt long tube, that is also fried. Just a toolmaker not electronic tech.
    Attached Thumbnails Attached Thumbnails what is this.jpg   IMG_3742.jpg   IMG_3744.jpg   IMG_3745.jpg  

    IMG_3746.jpg  

  20. #20
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    Re: A real bad day

    RPC = rotary phase converter

    Braking resistor = that big gray thing in the first picture ( the long gray tube). I'll try to give a simple explanation of its purpose without getting too technical. This will not be exactly technically correct and only applies to electric motors connected to VFDs and similar drives. When the motor is told to stop, it becomes a generator and the power needs to go some where, so rather than feeding the power back into the VFD, the VFD shunts off that excess power to the braking resistor which in turn converts the excess power into heat. Very much like the brakes in your car work, they convert the momentum of your car into heat.

    That CIMR-PCU40P2 VFD is a 460V, 1/2 HP rated. It will not work for your spindle motor. If your motor is rated at 7.5 HP then you need a VFD rated at 7.5HP, and in this case you need 230V (200 - 240) input, not 460V (380 -460)

    If you need help choosing a VFD, we'll be happy to help. And Mactec54 and I will argue about it But my favorite vendor is Automation Direct. https://www.automationdirect.com/adc...rpose/gs3-27p5
    Jim Dawson
    Sandy, Oregon, USA

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