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How This Heater get ON and OFF

  1. Mar 11, 2009 #1

    1.If i apply voltage 440volts at L1,L2,L3 the K3 (contactor) will get on automatically?
    2.How this SSR work and what should be the voltage at 4,5,6 and 7,8,9(X1 terminals)?

    The main thing i want to ask is how this heating 1 and heating 2 gets ON and OFF and at what voltage?

    Thank you.
  2. jcsd
  3. Mar 11, 2009 #2


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    Science Advisor
    Gold Member

    Welcome to PF ismat. It looks like the heaters are being controlled by SSR (which is a silicon controled rectifier, I think) and its ouput is controlled by pluses supplied to the + and - terminals. These pulses could be coming from a PID controller. And K3 appears to be contacts for a relay. Are there other parts of the circuit you are not showing?

    The voltage at 4,5,6 is just your 440V line voltage. The voltage at 7.8.9 will be pulsed 440V.
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