Product Description:

The PST6100.177-L, produced by Bosch Rexroth Indramat for the PST Thyristor Power Units series, is an air-cooled power unit used to regulate AC energy delivered to downstream equipment in automated plants. By triggering paired thyristors, it controls the effective voltage applied to a welding transformer, heater, or other inductive load, allowing the supervisory PLC to maintain stable process conditions. The module is designed for panel integration and accepts low-level firing signals from the system controller so that load current can be shaped in real time.

Its nominal system current is 130 A, meaning the silicon devices and busbars can conduct that RMS value continuously without exceeding thermal limits. A maximum transformer rating of 76 kVA is supported, allowing the unit to drive a secondary device of that size while retaining voltage control authority. The gating section is synchronized to line cycles at 50/60 Hz, so it can be installed on global power grids. A separate control supply of 24 V DC powers the firing logic and an internal timer circuit that handles pulse duration. The housing is rated IP20, which prevents accidental finger contact but requires a clean cabinet environment. Because conduction is limited to a duty factor of 50%, the unit dissipates 70 W of cabinet power loss and remains within its temperature range when a 50 mm² feeder is used. Overvoltage spikes on the mains are clipped by the built-in metal-oxide varistor, and integrated temperature monitoring shuts the unit down if excessive heat is detected.

The unit can operate in ambient temperatures up to 55 °C provided the incoming cooling air does not exceed 45 °C. Installation is permissible at elevations up to 2000 m above sea level without current derating. Air is pulled through the heat-sink fins by the cabinet ventilation system to support the air-cooled design. If the thermal limit is approached, the integrated sensors signal the controller to reduce the duty cycle.