Three Phase Thyristor Triggering Card – TSC-307

Libratherm offers Thyristor Switch Card TSC-307, which has been specially designed for switching 3 phase Resistive or Capacitive load. This SCR Switch card generates 3 sets of gate/cathode firing pulses to trigger 3 sets of back to back connected silicon controlled rectifiers (SCRs) or thyristors. The gate/cathode triggering pulses are generated using zero cross over cathodic firing techniques. The 3 sets of gate/cathode pulses (12pulses) are galvanically isolated using the on card ferrite core pulse transformers.

TSC-307 accepts 3 independent or one common linear signal of 4-20mA/0-5V/0-10V/Potentiometer or DC pulse/Contact input from temperature controller or from PLC and generates 3 independent gate cathode triggering pulses (G1K1+G2K2) for 3 pairs of back to back connected SCRs. Hence, one can control 3 independent single-phase loads or a single 3 phase load in star or delta configuration. The linear signal is pulse-width modulated to generate pulsating output with the variable on/off duty cycle time of 2 to 30 seconds, adjustable using on card potentiometer.

Each card can simultaneously trigger 3 sets of back to back SCRs or 3 thyristor modules (such as SKKT series of Semikron) to switch 3 phase load banks.

The SCR Firing Card TSC-307 has the provision to accept 2 external thermostat contacts, which can be used to operate the cooling fan mounted on the heat sinks and to trip the circuit in case of overheating. On card LED indicates the on/off status of incoming DC power supply, ON/OFF status of load banks, and status of heat sink temperature.