The 3UG3521-1AC48-0AA1: The 2...500 mA sensing range covers small motor loads, solenoid currents, or signal loops — typical for monitoring conveyor drives or pump motors in a panel. The 22.5 mm housing fits standard DIN-rail spacing, so it swaps into existing rail without drilling. One CO contact (changeover) gives a single alarm or trip output; for applications needing separate run and fault signals, the replacement 3UG4621 series offers more flexibility.
Siemens 3UG3521-1AC48-0AA1 Monitoring Relay, Discontinued, 2
MPN3UG3521-1AC48-0AA1
Siemens SIRIUS 3UG3521-1AC48-0AA1, discontinued monitoring relay, 22.5 mm, over/undercurrent 2...500 mA AC/DC, 1 CO contact, DC 24 V, screw connection.
Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Jul 2026
Product details
Frequently asked questions
What replaces the 3UG3521-1AC48-0AA1?
The official replacement is 3UG4621-1AW30. The 3UG4621-1AA30 can also be used if wired correctly, but it is not a pin-for-pin substitute.
What are the key specifications of the 3UG3521-1AC48-0AA1?
It is a 22.5 mm monitoring relay for over- or undercurrent detection, sensing 2...500 mA AC/DC, with one CO contact, 24 V DC supply, and screw terminals.
MPN
3UG3521-1AC48-0AA1