Product Description:

The PST6250.355-L is a thyristor power unit developed by Bosch Rexroth Indramat within the PST Thyristor Power Units series. As a solid-state switching assembly, it regulates incoming line power and delivers controlled AC energy to connected process equipment that requires accurate current control. The unit combines firing electronics, protective functions, and a communication interface in one cabinet-mounted package, which allows it to fit cleanly into industrial control systems that use coordinated power management.

It accepts a supply frequency of 50/60 Hz, allowing connection to standard industrial mains. The internal control electronics are powered from 24 V DC, which separates the logic supply from the power section. During operation, the thyristor stack carries a nominal system current of 200 A and can be used with transformers rated up to 250 kVA for high-power applications. Protection against accidental contact is provided by an IP20 housing, and switchgear losses are limited to 70 W to help reduce cabinet heat. Metal-oxide varistor suppression helps limit transient overvoltage on the mains, while terminals accept conductors up to 95 mm² and integrated temperature monitoring can reduce output or shut the unit down when thermal limits are reached.

Air cooling moves cabinet air across the heat sinks, and the incoming airflow must remain below the 55 °C ambient limit while the cooling air stays within the stated 45 °C value. Continuous conduction is limited to a 50% duty cycle so thermal loading remains within the intended operating range during repeated cycles. Reliable operation is permitted at installation altitudes up to 2000 m without performance loss. An INTERBUS timer supports coordinated firing control with upstream PLCs, and the 12.5 kg assembly can be installed alongside other drive components in a standard control cabinet.