Product Description:

The PST6100.336-L power unit is produced by Bosch Rexroth Indramat as part of the PST Thyristor Power Units series. It is intended for resistance welding installations where precise energy delivery is needed at each electrode. Operating as a controlled rectifier stage, the unit converts a plant two-phase supply into regulated current pulses for the welding transformer. This allows automated stations to apply repeatable heat input across multiple weld schedules and maintain consistent weld quality during production.

The unit has a nominal system current of 130 A on a dedicated two-phase line. It can drive transformer primaries up to 76 kVA when the duty cycle remains at 50%. The thyristors dissipate 70 W of heat, which is removed through an air-cooled path with cabinet air up to 55 °C. The housing has an IP20 rating that helps prevent accidental finger contact, so the unit is intended for installation inside an enclosure. Metal-oxide varistor overvoltage clamps protect the semiconductors from mains transients, and power cables up to 50 mm² can be connected to the terminals. The logic section supervises nine electrodes and monitors welding force with a resolution of 50 N so current control can follow clamp pressure accurately. A minimum pre-weld gate time of 16 ms is available for squeeze control before welding energy is released.

Up to 256 weld schedules can be stored in the controller layer. Each schedule can be addressed through the INTERBUS fieldbus, allowing the production cell to switch operating parameters during sequence changes. Reliable operation is maintained when incoming cooling air does not exceed 45 °C and the installation altitude remains below 2000 m. If either limit is exceeded, the current rating must be reduced. The timer can still start sequences at the minimum pre-weld interval, which helps keep timing behavior predictable in compact control cabinets.