Fuse - Want to make sure I do this right

Discussion in 'General Electronics Chat' started by james211, May 17, 2014.

  1. james211

    Thread Starter Member

    May 29, 2012
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    So here is my setup, I have an arduino that controls a 4 channel relay shield. Connected to the shield are two 115Vac peristaltic pumps. Since this is using 115Vac I want to make sure I fuse this correctly. Where is the proper place to fuse, and what type of fuse should I use?
     
  2. MrChips

    Moderator

    Oct 2, 2009
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    Find out how much current (max) at 115VAC the pump requires and choose a slow-blow fuse that is twice that current.

    For example, if the pump needs 1/2 A max, use a 1A SB fuse.

    The fuse goes on the 115VAC LIVE wire to the pump. The fuse must be the first item that gets connected to the LIVE wire. If you reside in North America, the LIVE wire is usually colored BLACK.
     
  3. james211

    Thread Starter Member

    May 29, 2012
    210
    2
    According to the spec sheet, the max current is 30mA. I searched mouser and jameco and I didn't come up with much other than through hole fuses, which doesn't seem easily replaceable. Mouser did have two cartridge fuses but they don't stock them. Any thoughts?
     
  4. enggricha

    Member

    May 17, 2014
    62
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    30 mA for a AC Pump? Sounds wrong to me. You might wanna check that again.
     
  5. james211

    Thread Starter Member

    May 29, 2012
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  6. enggricha

    Member

    May 17, 2014
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    I doubt you will find fuses for this current rating. If the idea behind using a fuse is to protect the relay board, then U can use a bigger rating fuse like a 500mA or so that is well within the range of the relay board. What do u want to protect the pump or the relay board?
     
  7. james211

    Thread Starter Member

    May 29, 2012
    210
    2
    The motors ideally as they are about $70/ea.
     
  8. enggricha

    Member

    May 17, 2014
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    in that case it would depend on the maximum current the motors can take safely.
     
  9. bertus

    Administrator

    Apr 5, 2008
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  10. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,509
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    All you need is enough fusing sufficient to protect the wiring to the pump, the peristaltic pump itself is high impedance shaded pole clock type motor, so if it were to jam or stall any current rise would be insignificant.
    Max.
     
  11. james211

    Thread Starter Member

    May 29, 2012
    210
    2
    Awesome! Thank you! On a side note, I'm looking for something else that maybe you guys can help me with.

    I want this project to have one power supply, but the motors run on 115Vac and the arduino and relay board run on low voltage DC power. Is something like this the best option? Or is there a better way to do it?
     
  12. enggricha

    Member

    May 17, 2014
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    1
    Dint know such fuses existed for such small current. Thanks for the info.
     
  13. BReeves

    Member

    Nov 24, 2012
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    Think I would just use a 3AG 1 amp fuse in a wired holder and be done with it. 1 Amp will not usually melt anything, cheap and easily available especially if you are desperate and all you can find open is an auto parts store.
     
    MaxHeadRoom likes this.
  14. bertus

    Administrator

    Apr 5, 2008
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