Product Description:

The PST6250.346-L thyristor power unit is produced by Bosch Rexroth Indramat within the PST Thyristor Power Units series. It serves as a solid-state switch that modulates mains voltage for heaters, electroplating baths, and other process loads, giving automation systems precise electrical power control without mechanical contactors. Because switching is handled electronically, the unit can regulate load power with repeatable timing during continuous industrial operation.

The unit can supply a continuous current of 200 A, allowing connected equipment to draw that magnitude indefinitely without overstressing the silicon junctions. A duty cycle of 50% commands its firing logic to conduct through only half of each timing window, which helps reduce delivered heat when full conduction is unnecessary. Its 2-phase thyristor topology uses paired devices on two mains phases to reduce current ripple while simplifying wiring. Control electronics are isolated on a 24 V DC supply so disturbances on the power bus do not affect trigger accuracy. Safety is reinforced by integrated temperature monitoring, which disables gate pulses whenever an internal sensor detects excessive chassis heat.

Air moves across the heat sinks because the unit is air cooled, removing a cabinet heat loss of 70 W. The open-frame design meets IP20, which helps prevent accidental contact with live parts. Operation is permitted at ambient temperatures up to 55 °C, provided inlet air remains below 45 °C. With a mass of 12.5 kg, the unit can be mounted on DIN rails or mounting plates without extra braces. Terminal connections accept conductors up to 95 mm², and an MOV network reduces incoming surges. A 2.2 kΩ de-excitation resistor dissipates stored energy after shutdown. The INTERBUS timer aligns pulses with supervisory logic, and altitude capability reaches 2000 m without derating.