SCR regulated auto battery charger

Discussion in 'The Projects Forum' started by tinkerman, Dec 25, 2012.

  1. tinkerman

    Thread Starter Member

    Jul 22, 2012
    136
    34
    Would like some help from some of you electronic whiz people understanding this control circuit. The design was taken from an industrial 3 phase 120 volt DC at 90 amp charger. Those units are still in service and have been almost trouble free for 40 plus years. In about 1984 I modified the control circuit for use on single phase 12 volt car charger rated at 25 A max. It works great. What I like about it is the current limit and the trickle charge features. The main transformer was made from an old 120/240 street light ballast. The CT I can't recall but it was probably some small 120 volt or similar transformer. It has one wrap of heavy wire from the main transformer for a primary. This is an old design with old parts by today's standards but I still plan to triplicate this board for use it two other similar sized car chargers I have in use.

    Never did have a full understanding on how this thing works though. I'm OK with the UJT and the PNP transistor but when we get to the 2N2222, the diodes, anti-hunt, current limit I'm basically lost.

    Anyone interested in some coaching?

    TIA
     
    Last edited: Dec 25, 2012
  2. tinkerman

    Thread Starter Member

    Jul 22, 2012
    136
    34
    Forgot the schematic! :mad:
     
    Last edited: Dec 26, 2012
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