Magnetic contact

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A magnetic contact is an automatic detector for monitoring z. B. doors , windows , roller doors or other moving parts. The magnetic contact consists of one or more reed contacts and a permanent magnet . If the door or window is opened by unauthorized persons, the reed contact opens because the magnet is removed (change in the magnetic field) and interrupts the zone . The reed contacts are usually cast in a waterproof plastic housing. The contacts are housed in solid aluminum housings to protect heavy goals and in the event of mechanical stress. These can also be run over with motor vehicles. The safest are so-called "external field-protected" or "double reed magnetic contacts", which trigger an alarm when a second magnetic field is applied.

Magnetic contacts certified by VdS Schadenverhütung (VdS) have a four-wire supply line and are provided with bridging protection. Reed contacts are sensitive to demagnetization . When assembling a magnetic contact and the associated magnet, attention must therefore be paid to magnetic insulation (e.g. by using non-magnetic screws) so that there are no negative influences on the magnetic contact.

Individual evidence

  1. ↑ VdS guideline 2311: VdS guidelines for burglar alarm systems - planning and installation. 2017-04 Chapter 9.2.1

literature