The Siemens 3UG5533-1AL30 is an analog monitoring relay for voltage supervision, covering 20 to 275 V AC/DC with internal power supply from 24 to 240 V DC and AC 50 to 60 Hz. It detects both overshoot and undershoot conditions, with independently adjustable ON delay and tripping delay from 0.1 to 30 seconds, and switches via a single changeover contact with screw terminals.
The 20 to 275 V AC/DC measuring range means it covers most common control voltages in industrial panels — 24 V DC, 48 V DC, 110 V AC, and 230 V AC — without needing a separate supply transformer. The internal power supply (24–240 V DC/AC) powers the relay itself from the same monitored circuit or a separate auxiliary, whichever is more convenient. Adjustable ON delay and tripping delay (0.1–30 s) let you ride through momentary dips or surges that shouldn't trip the line — useful for motor starting inrush or capacitor bank switching. Set the trip delay longer than the transient duration to avoid nuisance trips. The single changeover contact is adequate for signaling to a PLC input or dropping out a contactor coil. For applications needing two isolated signals, you'd add an auxiliary relay block.
RoHS compliant since June 2023, with a REACH Article 33 notification for lead (CAS 7439-92-1 > 0.1% w/w). The REACH declaration is available on request for your substance-of-concern register. Group code R711 and product group 5885 are the internal Siemens classifications — useful when cross-referencing in their system or ordering through Siemens Industry Mall.