How Do Heater Contactors and SSRs Control Heating Elements?

[ismat143]

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.

 

[dlgoff]

Welcome to PF ismat. It looks like the heaters are being controlled by SSR (which is a silicon controlled 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.

 

[oswaler]

I cannot provide a specific answer without knowing more details about the specific heater and its components. However, I can explain some general principles that may help you understand how the heater turns on and off.

1. Applying voltage at L1, L2, and L3 will activate the K3 contactor, which is a type of switch that controls the flow of electricity to the heater. When the contactor is on, it allows electricity to flow to the heater, turning it on. When the contactor is off, it stops the flow of electricity, turning the heater off.

2. The SSR (solid state relay) is another type of switch that uses electronic components instead of mechanical ones. The voltage at terminals 4, 5, and 6 controls the switching of the SSR, while the voltage at terminals 7, 8, and 9 controls the power supply to the heater. The specific voltage required at these terminals will depend on the specifications of the SSR and the heater.

In general, the heating elements in the heater will turn on when they receive the appropriate voltage and turn off when that voltage is removed. The exact voltage required will depend on the design and components of the heater. It is important to consult the manufacturer's instructions or a qualified electrician for the specific voltage requirements of your heater.