Siemens 3RR2142-1AA30 Monitoring relay, can be mounted to Contactor 3RT2, Size S0 basic, analog adjustment Apparent. Siemens 3RR2142-1AA30 is the exact printed commercial reference for a current monitoring relay in the SIRIUS 3RR Current Monitoring range. Siemens' official product description is: Monitoring relay, can be mounted to Contactor 3RT2, Size S0 basic, analog adjustment Apparent current monitoring 4...40 A, 50...60 Hz, 2-phase Supply 24 V AC/DC 1 change-over contact Monitoring for Current overshoot and undershoot Phase failure, Cable break with or without fault buffer ON delay 0-60 s Noise pulse suppression 0-30 s Switching hysteresis 6% Screw connection system.