Siemens 3UG3522-1AC20 Soft Starter For AC Motors

Siemens 3UG3522-1AC20 is a discontinued typemonitoring relay from Siemens, designed to monitor the current in AC circuits for overcurrent and undercurrent conditions. The unit is 22.5 mm wide and provides one changeover (CO) contact for signaling or interlocking, with screw-terminal wiring. It operates from AC 24 V at 50/60 Hz, and its current-monitoring range spans from 0.1 A to 10 A, allowing setpoint-based control without a separate sensor. The device is intended for use in machine controls and panel installations where precise current thresholds trigger alarms or protective actions. When replacement is needed, Siemens lists 3UG4622-1AW30 as a compatible alternative, noting that wiring compatibility must be observed. The 3UG3522-1AC20's legacy status means it may appear in older equipment catalogs and service parts inventories, often alongside other typemonitoring relays in the same family. For technicians maintaining legacy Siemens systems, this model provides a compact, screw-terminal current monitor that integrates with simple signaling circuits to flag deviation from nominal current levels.