A magnetically actuated hermetically sealed switch mounted in the elevator shaft or on the car to detect the position of a permanent magnet for floor-level, door-zone, or limit signalling.
Full Definition
Reed switches in elevator applications consist of two thin ferromagnetic contact blades sealed in a glass capsule (or plastic housing for modern types) filled with inert gas. When a permanent magnet (fixed to the car or to the shaft) passes within range, the blades flex and make contact, closing the circuit. Reed switches are used for: floor-level detection (opening door zone), re-levelling zone detection, pit and top-of-shaft limit positions, and directional proximity sensing. Rated operating voltage is typically 5–250 V AC/DC with switching current up to 0.5 A. Reed switches offer high switching speed, no mechanical wear, and intrinsic hermetic sealing (suitable for damp pit environments). They are more fragile to shock than inductive sensors and must not be installed where shock or vibration levels exceed the manufacturer's specification. EN 81-20 does not mandate reed switch technology specifically but the switch must fail to a defined safe state.
