Destructive switch contact test

Discussion in 'General Electronics Chat' started by Man_in_UK, Jun 5, 2015.

  1. Man_in_UK

    Thread Starter Senior Member

    May 13, 2008
    To settle a friendly argument I would like to build a tester that would stress mechanical switch contacts until they fail. There will be a counter to keep track of switch operations. Some sort of control over the intensity of the arc would be required so that I can chose to kill the contacts over a period of days, or weeks depending on the results I get.

    Can you suggest a circuit that would give a reasonably constant arc over a mechanical switch?

    I am only stuck on creating enough inductance to give an arc. The method of counting operations and timers etc is of no importance just now.

    All ideas welcome.
  2. crutschow


    Mar 14, 2008
    A power transformer has a high value of inductance. You could use the primary of any power transformer or the secondary of a low voltage transformer. Some experimentation would determine what works best.
    The amount of DC current going through the inductor before you open the contacts will determine the intensity of the arc up until the transformer core saturates.
  3. Man_in_UK

    Thread Starter Senior Member

    May 13, 2008
    So an old PC PSU giving 12VDC at about 25amp ..... straight into a hefty transformer with a big resistor to calm things down a bit ?
    Sounds simple enough. Good idea.
  4. dl324

    Distinguished Member

    Mar 30, 2015
    Or switch a 1HP motor; that should get you a good arc.