Product Description:

The PST625E.101-L thyristor power unit is manufactured by Bosch Rexroth Indramat as part of the PST Thyristor Power Units series. Designed for resistance welding and other high-current switching duties, it modulates line power through solid-state thyristors to supply up to eight electrodes in an automated station. Within an automation cell, the unit serves as the power stage that responds to controller timing commands and shapes current flow for repeatable weld cycles. Its role is to deliver controlled power during demanding production tasks while also supporting stable operation of connected welding equipment.

Energetic components are housed in an enclosure rated at IP54, so airborne dust and incidental splashing cannot easily reach the internal bus bars. The climatic category of 3K3 indicates suitability for industrial spaces with moderate humidity and vibration. Heat generated by the thyristor stack is removed through an air-cooled channel, and performance remains stable as long as incoming ventilation does not exceed 45 °C. Internal signal boards are separated from the power section and have additional IP20 touch protection. Surge stress on the mains is suppressed by an MOV network, and the field wiring lugs accept conductors up to 95 mm² for robust power connections.

The control section provides 16 opto-isolated digital inputs for external commands such as weld enable or squeeze confirmation, and it includes 12 transistorized digital outputs for status reporting to a line PLC. Parameter storage supports up to 64 machine programs, allowing different weld schedules to be selected for different workpieces without changing hardware. All low-level electronics are powered by a 24 VDC logic rail and dissipate only 10 VA, which helps limit added cabinet heat. A 24 V timer channel synchronizes firing angles with external events, while the integrated mini-DIN female port provides V24/RS232 access for setup and diagnostics. The unit can energize eight machine electrodes simultaneously, giving the welding cell flexible layout options.