Product Description:

The PST625E.101-W is a thyristor-based power control module produced by Bosch Rexroth Indramat within the PST Thyristor Power Units series. It is intended for machine-level resistance welding and similar high-current automation tasks, where transformer current must be controlled closely to maintain repeatable heat input. The unit can regulate welding current for as many as eight electrodes and is built for installation in a control cabinet with water cooling. In that role, it serves as the control link between the incoming line supply and the welding transformer.

During operation, the converter carries a nominal current of 230 A rms and can deliver up to 400 A on the transformer primary for short weld pulses. These currents are supported by an internal transformer rated at 155 kVA, which gives the unit enough magnetic capacity for stable pulse delivery under heavy welding loads. The semiconductor stack is limited to a 50% duty cycle, so the operating pattern must include equal on and off periods for thermal balance. An enclosure rating of IP20 requires cabinet mounting, and cooling is handled by a water-cooled baseplate that suits the stated climatic category. This arrangement keeps heat away from the power section while allowing the controller to remain part of a protected cabinet installation.

The control section is supplied with 24 V DC, and the timer circuit can execute 64 stored welding programs. A total of 16 digital inputs and twelve transistor outputs coordinate sensors and clamps, while a dedicated solenoid channel provides 1 A for valve actuation. Up to eight electrodes can be energized concurrently, which supports machine-based welding sequences that require several active current paths under one controller. Power wiring enters through terminals sized for 95 mm² conductors, helping reduce resistive loss while the coolant stabilizes the heat sink at 30 °C. The I/O layout allows the module to manage weld timing, clamping steps, and valve control within the same operating cycle.