Guard door interlock with spring-actuated lock
The Siemens 3SE5322-0SE21 is a SIRIUS mechanical safety switch designed for guard door monitoring on machinery. It uses a spring-actuated lock (closed-circuit principle) with an auxiliary release and a lock, so the door stays locked until the solenoid is energised — fail-safe on power loss. Rated thermal current Ith is 10 A, with switching capacity at 24 V rated 3 A. The contacts are slow-action with positive opening, meaning the NC contacts are mechanically forced open even if welded.
Locking force and actuator approach
Locking force is 1 300 N, which holds the guard door closed against operator force or machine vibration. The actuator accepts approach from 5 directions, simplifying alignment on hinged or sliding guards. The magnet coil runs on 24 V DC. The switch is supplied without an actuator — the separate actuator and tumbler design means you order the actuator head separately to match the guard geometry.
Environmental rating and wiring
IP66/IP67 protection lets it handle washdown and outdoor installation — the plastic enclosure resists corrosion. Screw terminals accept 1x (0.5... 1.5 mm²) or 2x (0.5... 0.75 mm²) solid/stranded. Three cable entries M20 x 1.5 give flexibility for top or side entry. Mounting position any, fastened by screw fixing.