Surge Protection Circiut Help

Discussion in 'Power Electronics' started by Slex04, Jun 1, 2017.

  1. Slex04

    Thread Starter New Member

    Jun 1, 2017
    3
    0
    upload_2017-6-1_14-52-54.png
    We are using this surge protection circuit on 16VAC transformers. What we found is that the 500mA fuse tends to open circuit regularly. There is never a sign of surge presence as there is no other reported damages to household equipment. We tried a slow-blow fuse but although less complaints there is still fuses that blow unnecessary.

    Has anyone got some advise for me. Is this circuit at fault or wrong components causing it to function at lower Voltages?

    I would appreciate some advice

    Regards

    Alex
     
  2. AlbertHall

    AAC Fanatic!

    Jun 4, 2014
    8,129
    2,015
    How much current is being drawn - how near is it to 500mA?
     
  3. Slex04

    Thread Starter New Member

    Jun 1, 2017
    3
    0
    Hi

    The Secondary or Load does not draw more than 3A. This is not more than 220mA at primary. The actual use of the the transformer averages at about 1A load..and this is why I suspect the surge protection circuit and not the load ..
     
  4. Sensacell

    Moderator

    Jun 19, 2012
    2,424
    802
    Re-size the fuse.

    44% of the trip current is way too close.

    Ask yourself- "what does the fuse prevent?"
    It's should prevent the wiring and components from catching on fire, this will happen at a much higher current than 500 mA.
     
  5. Slex04

    Thread Starter New Member

    Jun 1, 2017
    3
    0
    Thank you ..I realize the fuse is not for overload protection in this instance...so it should rather be 1A at least
     
  6. crutschow

    Expert

    Mar 14, 2008
    23,081
    6,848
    Does the 16V secondary have a bridge rectifier and a large capacitive filter?
    If so , it may be a turn-on current surge that is popping the fuse.
    A surgistor in series with the primary would help that.
     
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