Electric heater for building running off three-phase power supply has bridge-type rectifier with six diodes connected to smoothing circuit and impulse switching circuit

摘要

The heater is run off a 3x400V 50 Hz supply. The rectifier (1) produces direct current which is smoothed by a choke (2) in series with a pulse switching circuit (3). There is a filter circuit (S) in parallel with the choke and the pulse switching circuit, consisting of a capacitor (C) and a resistor (R) in series. Current from the pulse switching circuit energizes the heater (7). The pulse switching circuit consists of a bridge circuit with four IGBT (Insulated gate bipolar) transistors. It is controlled by a sensor (6) connected to a muP regulator (4) to regulate the heater output.