CD Automation supplies a wide range of thyristor power controllers designed for two phase switching of three phase heating loads.
An economical means of switching three phase heating loads is to switch two phases only, which is possible on delta or floating star loads with constant resistance heaters.
This method of switching works due to the fact that if two phases are switched off then the third phase has no return conduction path. Two phase switching can only be used with burst cycle or on/off firing of the thyristors. Phase angle firing cannot be used with this method.
Two key benefits of using two phase switching to control a three phase load include reduced cost with one less thyristor module in the circuit in addition to the thyristor power controller dissipating less heat because there are only two thyristor modules in the circuit. The reduced heat dissipation minimises enclosure fan cooling requirements and allows the control panel to run cooler, maximising the life of the power electronics.
CD Automation provides a wide range of two phase switching thyristor power controller assemblies from 30 amps per phase, with the REVO-S and REVO-M series right up to 2700 amps per phase with the MULTIDRIVE 2 PH controller.
All these thyristor power controllers have an RS485 port running Modbus RTU protocol, allowing the user to not only configure the thyristor remotely but also enable important electrical parameters such as current, voltage and power to be read. Fieldbus modules are available to convert Modbus RTU RS485 to Profibus, Ethernet, Devicenet and CANbus.
Semiconductor protection fuses are internal to the thyristor and are supplied as standard.
Practical Control Solutions
can advise on all aspects of selection, application, configuration and commissioning of thyristor power controllers.