Product Description:

The PST6250.332-L thyristor power unit is produced by Bosch Rexroth Indramat within the PST Thyristor Power Units series. It gates line voltage to maintain controlled current for industrial transformers and resistive loads in automated cells. Phase-angle firing is coordinated through an INTERBUS channel, so its internal timer aligns energy delivery with commands issued from higher-level motion or process controllers.

It accepts a three-phase supply between 400 V –20% to 600 V +10% at a line frequency of 50/60 Hz, and it is rated for a nominal system current of 200 A. When installed, the electronics section is powered from 24 V DC, with reliable operation maintained anywhere in the 19 to 30 V DC logic range. The power stage can feed transformers up to 250 kVA and includes a 2.2 kΩ de-excitation resistor to discharge energy when firing pulses are removed. A metal-oxide varistor handles overvoltage suppression across the anode-cathode path, and the 95 mm² terminal blocks accommodate the specified connection cross-section for incoming conductors. All process and diagnostic data are exchanged through an INTERBUS I/O port, and the integrated INTERBUS timer allows synchronized firing sequences within distributed control systems.

During operation, the unit uses air cooling, enabling continuous service inside panels that reach ambient temperatures as high as 55 °C. The permissible duty cycle is limited to 50%, so thermal loading remains within acceptable limits even when the assembly is installed at altitudes up to 2000 m. The enclosure carries an IP20 rating, preventing accidental contact with live parts but requiring installation inside a control cabinet. MOV-based overvoltage protection, the series resistor, and the dedicated logic source help protect the thyristors during mains transients. The product communicates exclusively by INTERBUS, and its mechanical layout reserves space for heavy conductors that match the stated connection cross-section.