Product Description:

The PST6250.331-L module is manufactured by Bosch Rexroth Indramat as part of the PST Thyristor Power Units series. Installed downstream of a PLC or motion controller, it delivers phase-angle or burst-firing control to high-current loads used in industrial automation. By replacing electromechanical contactors with semiconductor switching, the device reduces wear and supports rapid, repetitive power modulation that is essential for heating zones, transformer primaries, and similar controlled-energy applications inside modern production machinery.

With a continuous thermal capability of 200 A, the PST6250.331-L carries large load currents using only its internal air path. The gate and logic circuits draw a separate 24 V DC supply, isolating the control electronics from line voltage. It can modulate transformers up to 250 kVA, covering typical heating or welding installations. The housing has an IP20 rating, requiring installation in a closed cabinet while still preventing accidental contact. Rated operation extends to 55 °C ambient, supported by the built-in air-cooled heat sink. A 2.2 kΩ de-excitation resistor speeds current decay, a MOV clamps line surges, and inlet air may be 45 °C without derating.

During maximum service the cabinet dissipates 70 W, a value used for enclosure thermal calculations and fan sizing. The controller permits a maximum duty cycle of 50 %, allowing symmetrical bursts without overheating the silicon. Installation is approved up to 2000 m altitude, where reduced air density is offset by the limited dissipation. Field wiring can reach 95 mm², and the recessed mounting style keeps power bars flush with the panel door. Communication with higher-level systems is handled through the INTERBUS timer interface, and the product operates as a thyristor power unit for standard zero-cross and phase-angle control strategies. The final assembly weighs 12.5 kg, which should be considered during panel mounting.