Interesting videos on breakers and fuses

Rybren
Rybren Solar Expert Posts: 351 ✭✭
in Solar Beginners Corner #1
Someone had posted these videos on the Midnite forum and I thought it would be useful to share them here.

This is a cut and paste of the original post..

Research institute of sustainable energy at Murdoch UNI in West Australia did tests on the wrong polarity of DC breakers, mini DIN AC breakers & switches on DC.
here are some videos showing what can happen:

http://www.youtube.com/watch?v=a8f5pYOLn6I

http://www.youtube.com/watch?v=4kcwgPs-DBE

http://www.youtube.com/watch?v=ghBBW9aytzk

http://www.youtube.com/watch?v=Zp5ohYwUYpE

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Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,590 admin
    #2
    Re: Interesting videos on breakers and fuses

    Some of those breakers made very sad sounds. :cry:

    I saw all the tests with the breakers mounted horizontally--I wonder if they were mounted vertically, if it would have made a difference (probably not).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    #3
    Re: Interesting videos on breakers and fuses

    I think it would have been MORE spectaaxular than it was... (not a typo, just a new word)
     
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #4
    Re: Interesting videos on breakers and fuses
    BB. wrote: »
    Some of those breakers made very sad sounds. :cry:

    I saw all the tests with the breakers mounted horizontally--I wonder if they were mounted vertically, if it would have made a difference (probably not).

    -Bill
    Not in the least. The problem, I believe is that magnetic arc deflectors and arc chutes are pointing in the wrong direction when you reverse the current. The overcurrent trip mechanism may have a permanent magnet bias too, since the ones they showed first are DC-only.
    SMA SB 3000, old BP panels.
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  • williaty
    williaty Solar Expert Posts: 60 ✭✭
    #5
    Re: Interesting videos on breakers and fuses

    That makes me wonder if the Square D QO breakers that I'm using are polarity sensitive. They rated to 48VDC but don't have polarity markings on them.
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #6
    Re: Interesting videos on breakers and fuses
    williaty wrote: »
    That makes me wonder if the Square D QO breakers that I'm using are polarity sensitive. They rated to 48VDC but don't have polarity markings on them.
    If they do not have polarity markings on them, then they are not polarity sensitive and have been tested with both polarities.
    For voltages as low as 48 volts, extinguishing an arc is much easier. And for AC, since the current goes through zero twice per cycle, the arcs tend to extinguish themselves if you can get enough distance between the contacts.
    SMA SB 3000, old BP panels.
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