Magnetic reed switch Schmersal
Magnetic reed switches are often used to replace mechanically actuated limit switches with plungers, roller and turning levers and as important connecting element for non-contact limit switches. In the elevator industry, magnetic reed switches are used for positioning and control. They are preferably used where mechanically actuated limit switches no longer function satisfactorily due to unfavourable operating conditions such as high or low start-up speeds, high switching frequencies, strong dust or dirt influence, high humidity, chemical atmospheres or large fluctuations in operation intervals.
The magnetic reed switches consist of two units, the switch and the actuating magnet. The contacts of the switch are protected from dust, humidity and corrosion through the enclosed glass tube. Magnetic reed switches thus have an extraordinarily high contact reliability. The enclosures are made of thermoplastic; the versions for the different applications are rectangular, cylindrical or flat. Magnetic reed switches are fitted with mounting holes, threaded bolts, screwed flanges or on C-rails. They are provided with a central fixing screw or slotted holes for the adjustment. BN 260 is highly insensitive to transverse misalignment.
Design and function
There are normally open (NO), normally closed (NC) and bistable contacts; with some types, the switching conditions are indicated by LED. The switches are actuated with actuating magnets with and without enclosure.
Depending on the type of switch, a specific actuating magnet for lateral or front actuation as well as different actuating distances can be chosen. In order to avoid malfunctions, the actuating planes are provided with symbols. Because of their bias voltage, bistable contacts are the most sensitive switches. Depending on the application, magnetic reed switches with pre-wired cable, cable entry or connectors are available. Protection class is up to IP 67.