Need help for motor driving with triacs

Discussion in 'The Projects Forum' started by mesuthh, Jan 17, 2011.

  1. mesuthh

    Thread Starter New Member

    Jan 17, 2011
    8
    0
    Hello people;
    I really need help friends [​IMG]
    I am tring to drive a single phase (230V AC) motor 4A with BT137(8A), but triac gets hot like 35 celcius degree (even I am using cooler) and after some switching it is getting failed. So that later on I have changed the triac with BTA41(40A) and bigger cooler, but it is still hot around 30 degree, and in one week BTA41 also gets failing. I am tring to drve the triac with Moc3041, and I am tring to switching the triac when 5Vdc available on Moc3041.
    I have tried to use snubber but it is not solving the problem
    you can reach the view of my circuit on [​IMG] here I am triying drive the motor with 5V dc control to moc3041 so triac fries and the motor starts, and one more think I am also drving a 25uf 400 V capacitor (paralell with the motor) with that motor for compansating

    if someone has an advice I will be really thankfull to him/her
    Regards
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
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  3. mesuthh

    Thread Starter New Member

    Jan 17, 2011
    8
    0
    Dear beenthere ;
    No, it is not for speed controll, just for switching
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
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  5. mesuthh

    Thread Starter New Member

    Jan 17, 2011
    8
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    I will try thank you very much
    by the way Do we need snubeer network
     
  6. eblc1388

    Senior Member

    Nov 28, 2008
    1,542
    102
    It is a bad idea to place in series a LED with the MOC3041 at 5V drive voltage and I'm going to tell you why.

    The MOC3041 IR emitter requires a typical of 30mA for reliable operation and at that current the typical voltage drop is between 1.25V and 1.5V. With the added LED voltage drop of 2~3V(depends on color), you don't have much headroom for the series resistor.

    30mA for a common LED might also be a bit too high.

    If you want indication, connects them in parallel, LED and IR emitter each having its own current limiting resistor.
     
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