The Siemens SIRIUS 3RV1982-1AA0 is an undervoltage release designed for the 3RV1.6, 3RV1.7, and 3RV1.8 series of motor starter protectors. It operates on a 24 to 30 V AC/DC control supply, tripping the upstream circuit breaker when the control voltage drops below the dropout threshold — a standard method for preventing motor restart after a supply dip.
This undervoltage release snaps onto the side of the 3RV1 circuit breaker, occupying no additional DIN rail space. The 24–30 V AC/DC control coil is wired in series with the emergency-stop or undervoltage monitoring circuit — when the control voltage disappears, the release mechanically forces the breaker to trip. Verify the coil voltage matches your control transformer tap before wiring.