What will happen at primary side of transformer

Discussion in 'General Electronics Chat' started by ranatungawk, Sep 6, 2009.

  1. ranatungawk

    Thread Starter AAC Fanatic!

    Oct 30, 2008
    A I have a 230V/12V, 3A step-down transformer.

    What will happen at primary side of transformer if I attach a 12V/5A device at secondary side? Will primary side attributes (such as voltage or current) change?
  2. Externet

    AAC Fanatic!

    Nov 29, 2005
    The increased current demand on the secondary will increase the current on the primary and being beyond the 36 VA rated capability of the transformer, it will overheat. It may fail with time running in that condition.
  3. bountyhunter

    Well-Known Member

    Sep 7, 2009
    The voltage on the secondary will also drop due to the increased voltage drop across the winding. It will overheat the transformer.
  4. marktchaos

    New Member

    Sep 7, 2009
    Also if the transformer is struggling to provide the extra current it will be operating closer to magnetic saturation and if it goes into saturation really high currents will flow in the primary and it could fail catastrophically. One hopes it was designed with more margin of safety than that though.