Thyristor heat dissipation

Discussion in 'General Electronics Chat' started by mortezab, Jul 7, 2011.

  1. mortezab

    Thread Starter New Member

    Jul 7, 2011
    I would like to compute the heat dissipation of a thyristor which is used in Soft-Starters. As far as I know, heat dissipation in thyristors is composed of the two terms, P=V.I(av)+R.I(av)^2. To understand each term of this equation, I am looking for some references in which there is a good description for heat dissipation calculation of thyristors.Thank you in advance for your help.
  2. PackratKing

    Well-Known Member

    Jul 13, 2008
    This info should be on your data sheet...........

    Otherwise, depending on what you are softstarting, anywhere from a "Dremel" hand tool, to a 5 hp 3-phase motor fer instance.........I would start with a heatsink that can dissipate at least ten watts, and use a infrared spot thermometer[ pyrometer ] if you prefer, and closely track temp rise on at least ten start cycle, and re-evaluate your heatsink requirements accordingly.

    Calculations are ok, real time operation doesn't always listen, as there are no dependable mathematic variations to cover how "joe schlameel" runs the equipment :D