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  1. #1
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    Anywhere to buy a 3kw spindle in Australia?

    Hi, Does anyone know where to get a 3kw water cooled spindle in australia, the bearings are going in mine and its only 6 months old, so need something quickly to replace it while I get it fixed,

    Thanks

  2. #2
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    Re: Anywhere to buy a 3kw spindle in Australia?

    How on earth did you manage to go through the bearings in 6 months ? ? ?

    Cheers
    Roger

  3. #3
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    Re: Anywhere to buy a 3kw spindle in Australia?

    I have no idea, from what I understand its a 4 bearing model with italian bearings, but it screams constantly when its on, just in last couple days, I have been cutting a lot of acrylic but I wouldnt say excessive cutting as I am only really running it 3-4 times a week.
    Its a 3kw gdz100-3B water cooled spindle, chinese jobby.

  4. #4

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    Re: Anywhere to buy a 3kw spindle in Australia?

    Quote Originally Posted by RCaffin View Post
    How on earth did you manage to go through the bearings in 6 months ? ? ?

    Cheers
    Roger
    Very easy if he has poor Grounding and high Rotor voltage, Rotor voltage does in most motor bearing when using VFD Drives
    Mactec54

  5. #5
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    Re: Anywhere to buy a 3kw spindle in Australia?

    Um - arcing across the bearing balls from the VFD? Yeah, weird, but that could do it.

    Have to strip it down and inspect the bearing. A carbon brush on the shaft for earthing might be needed.
    If you could identify the bearings and buy in replacements, you should be able to swap them over in one day. That might be as fast as anything else.

    Cheers
    Roger

  6. #6
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    Re: Anywhere to buy a 3kw spindle in Australia?

    Thanks for the replies guys, the manufacturer is sending me out the bearings to replace, I also ordered a second spindle from them, so I can reduce the down time on the machine, basically swap it out while I fix the other one, then atleast I will have a spare if something happens again, is there a way I can test if my spidle is arcing out from my VFD?

    Thanks
    Lyndon

  7. #7
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    Re: Anywhere to buy a 3kw spindle in Australia?

    the manufacturer is sending me out the bearings to replace
    OK, this manufacturer is worth knowing about. Very different from so many Chinese eBay distributors, who know nothing.

    Yes, you can check the spindle yourself. Simply put an AC voltmeter from the shaft to your 0V point - like maybe the frame. Just press a bit of wire against the spinning shaft (somewhere smooth!): any contact will do. If there is more than (say) 0.5 VAC, then there could be arcing through the bearings. This is a problem.

    Now, if there is a problem there, a simple carbon brush pressed against the shaft anywhere and connected to gnd/0V should help immensely. The arrangement needs to PRESS the brush against the shaft, but not all that heard. A kluge would suffice

    Of course, if the brush erodes away quickly or you end up with a big arc-mark around the shaft, then something is seriously wrong with the motor/spindle!

    Cheers
    Roger

  8. #8

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    Re: Anywhere to buy a 3kw spindle in Australia?

    Quote Originally Posted by RCaffin View Post
    the manufacturer is sending me out the bearings to replace
    OK, this manufacturer is worth knowing about. Very different from so many Chinese eBay distributors, who know nothing.

    Yes, you can check the spindle yourself. Simply put an AC voltmeter from the shaft to your 0V point - like maybe the frame. Just press a bit of wire against the spinning shaft (somewhere smooth!): any contact will do. If there is more than (say) 0.5 VAC, then there could be arcing through the bearings. This is a problem.

    Now, if there is a problem there, a simple carbon brush pressed against the shaft anywhere and connected to gnd/0V should help immensely. The arrangement needs to PRESS the brush against the shaft, but not all that heard. A kluge would suffice

    Of course, if the brush erodes away quickly or you end up with a big arc-mark around the shaft, then something is seriously wrong with the motor/spindle!

    Cheers
    Roger
    It is very normal to have rotor voltage more so when using a VFD Drive, there is nothing that is seriously wrong with the motor / spindle if it has a shaft voltage

    You can't use a standard meter to measure the shaft voltage it will give you a false reading or no reading at all
    Attached Files Attached Files
    Mactec54

  9. #9
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    Re: Anywhere to buy a 3kw spindle in Australia?

    @mactec

    No, I was not suggesting using a common voltmeter to measure the voltage, just to detect whether or not there seems to be a small or large voltage. Measuring requires a knowledge of the waveform AND how the meter converts the incoming AC voltage to DC. That is not needed here.

    Despite that, my thanks to you for the PDF. It was extremely educational. Clearly there is much to learn about the differences between a cheap commercial unit and a nice theoretical version of a 3-phase VFD. I was assuming that mfrs would filter their waveforms into clean balanced sine waves: silly me. (Me, I use industrial brushed DC motors and have none of the problems.)

    Just as a niggle, I strongly dispute Marathon's claim that there is any large difference between their conductive brush ring and a common carbon brush, but one must allow for the spin (or ignorance) of their marketing dept. The bit about maintenance of carbon brushes should be weighed against the fact that cars will often go for hundreds of thousands of miles without a change of brushes on their alternators (assuming they have them).

    Cheers, and thanks
    Roger

  10. #10

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    Re: Anywhere to buy a 3kw spindle in Australia?

    Quote Originally Posted by RCaffin View Post
    @mactec

    No, I was not suggesting using a common voltmeter to measure the voltage, just to detect whether or not there seems to be a small or large voltage. Measuring requires a knowledge of the waveform AND how the meter converts the incoming AC voltage to DC. That is not needed here.

    Despite that, my thanks to you for the PDF. It was extremely educational. Clearly there is much to learn about the differences between a cheap commercial unit and a nice theoretical version of a 3-phase VFD. I was assuming that mfrs would filter their waveforms into clean balanced sine waves: silly me. (Me, I use industrial brushed DC motors and have none of the problems.)

    Just as a niggle, I strongly dispute Marathon's claim that there is any large difference between their conductive brush ring and a common carbon brush, but one must allow for the spin (or ignorance) of their marketing dept. The bit about maintenance of carbon brushes should be weighed against the fact that cars will often go for hundreds of thousands of miles without a change of brushes on their alternators (assuming they have them).

    Cheers, and thanks
    Roger
    The VFD output PWM is nothing like a sine wave may be you can tell them how to fix this 60 year old problem

    It's not Marathon's conductive brush, it what is used throughout the industry and is superior to any kind of carbon brush will ever be, there is zero maintenance and 360 degree contact with this conductive brush design and is used by all the major AC motor manufactures they add them inside the motors in the manufacturing process, the outside brush is an option for those that don't have them, alternators have brush problems, go to an auto parts store and ask them how many alternators or repair kits they sell a week
    Mactec54

  11. #11
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    Re: Anywhere to buy a 3kw spindle in Australia?

    Thanks for the info, tho somewhat over my head, but I will find someone to check it out based on your input, I bought the machine direct from the manufacturer in china and not thru ebay, they gave me a 1.5yr warranty. having said that they wouldn't replace the motor until it actually blows or seizes effectively, but I did manage to get the bearings from them. My entire machine runs on single phase 220v. It uses a fuling inverter and has a single phase emi filter, pics attached.

    Thanks
    Lyndon

  12. #12

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    Re: Anywhere to buy a 3kw spindle in Australia?

    Quote Originally Posted by dragon_sa View Post
    Thanks for the info, tho somewhat over my head, but I will find someone to check it out based on your input, I bought the machine direct from the manufacturer in china and not thru ebay, they gave me a 1.5yr warranty. having said that they wouldn't replace the motor until it actually blows or seizes effectively, but I did manage to get the bearings from them. My entire machine runs on single phase 220v. It uses a fuling inverter and has a single phase emi filter, pics attached.

    Thanks
    Lyndon
    The filter helps the Main input Power supply it would need an output reactor between the spindle and VFD to have a small affect on the Spindle Rotor Voltage, but this causes a loss in performance, no amount of Filter protection can prevent Rotor voltage completely, How ever that's what ceramic Bearings are mostly used for


    What size is your spindle motor as that filter looks to be under rated @ 20A
    Mactec54

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