The Siemens 3UG4501-1AA30 is a SIRIUS level monitoring relay with analog setting, designed to detect conductive liquid levels in tanks, wells, or sumps using two or three probe electrodes. It operates on a 24 V AC/DC supply and switches loads up to 3 A at 250 V or 400 V (50/60 Hz), making it suitable for direct control of small pumps, valves, or alarm circuits without an intermediate contactor.
The 3 A switching capacity at 250/400 V covers most pilot-duty and small motor loads; for higher currents, use the relay to drive a contactor coil. The 22.5 mm width fits standard DIN-rail spacing; screw and snap-on mounting allows both permanent and tool-less installation.
No last-time-buy or phase-out constraints apply.
An external reset input (terminal) allows remote reset of the relay after a level trip — useful for unattended pump stations. The relay provides galvanic isolation between input (sensor) and output (load) circuits, preventing ground loops in multi-tank installations.
The 3UG4501-1AA30 carries CE marking and is designed to meet IEC/EN 60947-5-1 and related standards. RoHS and REACH declarations are available from Siemens upon request.