This is my first time to make a heater system, so I hope someone can help me. We try to design Heater application. We imagine that there is a thermocouple fit in the middle of the region we want to control by heater. Thermocouple will be connected to PID temperature conntroller. The output of the controller will be 4...20mA or 0...10VDC. I will use this signal to control the output power of a solid state contactor. I connected the heater to a transformer (380/110VAC) to increase the output current. We have the suggestion to use solid state contactor to control input power of the transformer. So please send to us recommended selection of SSC for our application or give me another description.

 

Commercial devices known as "phase angle fired SCRs" with a soft start are used to drive the primary of a transformer.

SCRs are sized for the amperage needed at whatever the transformer's primary voltage is.

The soft start feature is used on inductive loads.

These devices come with a control signal input compatible with the controller's 4-20mA output. It's straightforward: mount them, wire them, use them.

I use Control Concepts brand, but there are dozens of manufacturers of these devices.

Bud

 

What is the amperage of the heater? If it is less than 100 amps and at 110 volts, a low cost solid state contactor such as http://www.power-io.com or www.omega.com would work fine. Install it between the transformer and the heater. If the amperage is higher, then you may need a "phase angle" power controller in front of the transformer, instead. These are available in any amperage but at 3-7 times the cost. Try http://www.watlow.com or http://www.eurotherm.co.uk