Replacement fuses don't work

Discussion in 'The Projects Forum' started by NathanielZhu, Oct 30, 2015.

  1. NathanielZhu

    Thread Starter Member

    Dec 5, 2011
    39
    2
    I have a centrifuge that has an 8A 250V fuse that blew when I turned up the RPM to Max.

    So I went to microcenter and ebay to find a replacement fuse. The origional fuse does not indicate whether it was a fast blow or slow blow fuse so I decided to try both.

    I bought 8A, 250V fast blow fuse from microcenter and 8A slow blow fuses from ebay.

    Inserting either of these fuses and powering on the machine results in an instant spark and destruction of the fuse.

    just wth is going on? It makes makes no sense to me.

    The origional fuse had a different internal wire than the replacements but that shouldn't matter. It should be sold to perform as it is rated to perform but they don't.

    The origional had a glass fuse with a wire coiled around something white. The replacements were straight metal filament.

    Should I go up to 10A?
     
  2. #12

    Expert

    Nov 30, 2010
    16,283
    6,795
    The original fuse is slow blow.
    Unfortunately, if your machine blows a slow fuse just because you turned it on, the centrifuge is broken.
     
  3. NathanielZhu

    Thread Starter Member

    Dec 5, 2011
    39
    2
    To be sure, could I power on the device by shorting the circuit without the fuse to test whether the device powers on or does the fuse provide any essential function like adding resistance aside from just blowing?
     
  4. #12

    Expert

    Nov 30, 2010
    16,283
    6,795
    The fuse keeps the machine from going up in flames if it is really broken. Short the fuse AT YOUR OWN RISK!
     
  5. NathanielZhu

    Thread Starter Member

    Dec 5, 2011
    39
    2
    haha. I'll tell you how it goes. If I don't post back- probably means I'm a pile of ashes.

    edit*
    Yeah you were right. A Capacitor caught on fire
     
  6. RichardO

    Well-Known Member

    May 4, 2013
    1,235
    384
    Slow blow fuses look different than fast blow fuses. If both of your fuse types look the same I am guessing the slow blow fuses aren't.

    I don't think fuses normally say "slow" on them. Check for part numbers on both the original and the replacement slow blow fuses.
     
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