Prevention of Arcing.

Discussion in 'General Electronics Chat' started by cjdelphi, May 27, 2009.

  1. cjdelphi

    Thread Starter New Member

    Mar 26, 2009
    While reading other peoples posts here I usually think about them and think up something else for fun.

    The number 1 reason for degradation or at least a main reason, for killing a mechanical switch is the arching that takes place everytime you switch something on and off other than say a piston type switch where it's on all the time and when you push the button you actually switching on a solid state relay or transistor of some kind to serve the power hungry device.

    What about something which when switched on powers up from 1v > XXv for example 12v power supply wouldn't a startup procedure of say 1v 2v > 12v which takes a couple of seconds prevent the arching? and thus prolong the switch?

    I dunno, the switch can easily be replaced i guess which is cheaper than having the circuit replaced also would a startup procedure like that degrade the life of sensitive electronics?

    I'm just kicking around thoughts (i'm bored)
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    While voltage can encourage arcing due to it's magnitude, the current through the contacts (and between them during the arc) is what causes the contacts to burn.

    I've got one toggle switch that has been in use for 29 years without failing.
  3. R!f@@

    AAC Fanatic!

    Apr 2, 2009
    the way I see it it's inductive loads that creates arc in mechanical switches.
    U know when the EMF collapse the voltage will develope across the opening switch, and since AC is faster then a spring loaded switch, the air gap in the switch as the contacts separate breaks down and igniting air to a spark. And after like a long life cycle of on and off's the contacts will be melted
  4. studiot

    AAC Fanatic!

    Nov 9, 2007
    It's called soft start and is also used for other purposes eg to prevent the thump from speakers at turn on.

    Mercury wetted switches or switches which work by dipping the contacts into liquid mercury are designed to avoid arcing.
  5. radiohead

    Distinguished Member

    May 28, 2009