SINGLE PHASE THYRISTOR POWER REGULATOR.

Discussion in 'The Projects Forum' started by mnyakuzi, Feb 4, 2016.

  1. mnyakuzi

    Thread Starter New Member

    Feb 4, 2016
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    hi all,
    am trying to make a single phase thyristor power regulator for heating purposes which can accept a 4-20mA single from the plc and control the firing angle and hence control the power to the load and in my case electric heater. through a feedback from the temperature controller.
    ive tried in vain to find a circuit for the same. any ideas will be highly appreciated.
     
  2. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    Welcome to AAC!
    For heating control, burst mode (i.e whole cycle switching) would be better than phase-angle control in that it would produce less EMI.
    What voltage/power rating does the heater have?
     
  3. mnyakuzi

    Thread Starter New Member

    Feb 4, 2016
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    0
    basically my project is plc controlled heating of electric furnace
    trying to make a thyristor controller and use the 4-20mA for analogue control and also be able to record the temperature trends. making the controller has been an obstacle so far Since this is for project purposes,its only 500w heater,240v ac,50hz
     
  4. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    Is this a school/college project?
     
  5. crutschow

    Expert

    Mar 14, 2008
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    Easiest is just to use a SSR (Solid-State-Relay) to control the heater using a burst-mode control as Alec_t said.
    Use the control signal to adjust the duty-cycle controller to turn the power ON for several cycles and then OFF for a number of cycles.
    The ON/OFF ratio determines the average power.
    Can you program the PLC to generate this variable duty-cycle in response to the temperature?
     
  6. ian field

    Distinguished Member

    Oct 27, 2012
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    In that context; a zero crossing type SCR/triac opto-coupler driving the SCR would be better than a common or garden SSR.
     
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