TRIAC power controller for electric heaters RNS

Applications

Applied in ventilation systems for regulating the power output of electric heaters with load current rating up to 120 A.

Design and control

The controller casing is made of flame-retardant thermoplastic. The controller is equipped with an ON/OFF button and a heating temperature control knob. Electric power output is regulated by proportional connection and disconnection of the full load depending on the pre-set heating temperature. The RNS-16 is capable of controlling only one heating stage. Unlike the smaller models, RNS-25 are capable of controlling
one or three heating stages with the power output equal or exceeding that of the controlled stage. The power output of the first stage is controlled steplessly by switching the full load on and off. The second and third stages are controlled in steps. For overheating
protection the electric heater must be equipped with two built-in thermal contacts: TK50 with intervention temperature of +50 °C and automatic restarting and ТК90 with response temperature of +90 °С andmanual restarting. The air temperature is set by means
of the built-in potentiometer or the external control device generating a 0-10 V control input for increasing the duct temperature proportionally in the range from 0 to +40 °C. The duct temperature sensor must be installed downstream of the heater in the direction of the air stream at the minimum distance of 50 cm from the heater. If the controller runs in the heating power output mode in disregard of the temperature sensor feedback, no duct temperature sensor is necessary whereas the heating power output is regulated in the 0 to 100% range by means of the 0-10 V control signal.

Protection

Input circuit of the power controller has a thermal fuse for overload protection.

Mounting

The controller is designed for indoor mounting. Installation shall be performed with respect to the free air circulation for inner circuit cooling. The controller is for vertical installation. Do not install the controller above the heaters and in bad air convection areas.