Damaged FW8S-STXL drive chain

Discussion in 'Filter Wheels' started by BrianR, Dec 8, 2019.

  1. BrianR

    BrianR Standard User

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    Dec 8, 2019
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    Hi,

    The drive chain on our campus observatory's FW8S-STXL has lost enough teeth in one spot that it doesn't always properly mesh with the drive wheel that is attached to the motor. The motor stutters while it is trying to keep moving and most of the time it requires a power-cycle to work again. (We've watched this happen with the cover off to verify the behavior.) Does a replacement chain exist for this?

    Thanks,

    Brian
     
  2. Colin Haig

    Colin Haig Staff Member

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    Oct 27, 2014
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    My colleague @Tim should be able to help you with a replacement part when he is back at work on Monday.
    Can I get the serial number of the Filter Wheel from you?
    Also, do you have any idea what the cause is of the teeth being damaged/worn out?
    e.g. are the scraping on something inside the filter wheel?
     
  3. BrianR

    BrianR Standard User

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    Dec 8, 2019
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    Thanks for the prompt response. I need to correct myself and say that this is a FW8G instead of FW8S. The serial number is 1311.

    It's not clear what caused the issue. The missing teeth are on the cover side, away from the filter wheel. The detached teeth were in the enclosure when I took the cover off, and it looked like they had come off whole rather than being worn down. The problem has been happening for a while, but became worse, so the teeth may have come off one-by-one. The cover is back on because we plan to observe tonight, but I will double-check the inside of the cover next chance I get. I've included a (slightly out-of-focus, sorry) image of the damaged part of the chain: IMG_20191208_000554863.jpg
     
  4. BrianR

    BrianR Standard User

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    Dec 8, 2019
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    Also, if it matters, we have the standard cover on it, rather than the self-guiding cover.
     
  5. Doug

    Doug Staff Member

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    Wow, that's extremely unusual. I'm not aware of a single instance of the chain breaking in that fashion. In fact they're rated for operation at something like 100X the speed we are operating them at.

    Check to make sure that the mechanism is operating smoothly. You should be able to turn the wheel fairly easily by hand.
     

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