Product Description:

Bosch Rexroth Indramat manufactures the PST6250.330-L thyristor power unit within the PST Thyristor Power Units series. This module is installed in heating, melting, or high-current process equipment to modulate mains power through phase-controlled silicon devices, allowing precise regulation of resistive or inductive loads. By supplying controllable AC power, the unit interfaces with PLCs and fieldbus systems to integrate thermal processes into automated production lines and protect downstream components from inrush and line disturbances.

The unit operates with a nominal load current of 200 A, allowing it to feed large heating elements without saturation. Its internal trigger electronics synchronize with the mains at 50/60 Hz, ensuring stable phase control regardless of regional supply frequency. All logic circuits are powered from a separate 24 V DC control supply so the power section can be isolated when needed. During operation, cabinet dissipation is limited to 70 W, a value that guides enclosure ventilation design. An IP20 protection rating supports placement inside guarded panels, while MOV overvoltage suppression shields the thyristors from line spikes. Connection lugs accept conductors up to 95 mm², and the recessed mounting frame simplifies flush installation in control cabinets.

For intermittent thermal loads, the power stage is rated for a 50% ED duty cycle, meaning half-period energization within each minute to reduce semiconductor temperature rise. The unit can operate at installation heights up to 2000 m and at ambient temperatures reaching 55 °C; inlet cooling air must not exceed 45 °C to keep the air-cooled heat sink within safe limits. The assembly weighs 12.5 kg, so it can be handled without lifting equipment. Integrated temperature monitoring activates when heat sink limits are approached, and the INTERBUS timer coordinates firing sequences with field PLC timing. Parallel, serial, and fieldbus interfaces report status and receive setpoints for closed-loop control.