LSA Protection Magazine

- Sep 21, 2017-

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     In line with signal potentials, a distinction is made between 3-point and 5-point protection.

     In case of connection modules, only 3-point protection is possible.

     Switching modules are basically recommended for 5-point protection (components in the signal path) because - once the protective plug has been removed - the contact in the module is open, so that possible faults cannot make their way to the downstream network. 5-point protection can also be implemented using disconnection modules.

    KRONE supplies various types of protective circuits:

􀂄     3-point protection: pure overvoltage protection (high-voltage or secondary protection)

    􀂄 5-point protection: overvoltage protection combined with current protection

    􀂄 5-point protection: graded protection (high-voltage and secondary protection with current protection).

Fail-Safe

     Protective circuits with an integrated fail-safe feature are highly recommended. Components for overvoltage protection are usually designed for pulse-shaped loads only. Therefore, if permanent overloads are possible (e.g. mains contact), a safe short-circuit to earth must be ensured. Overloaded or overheated protection components would not only lose their protective function, they could cause fire or an explosion thereby leading to considerable damage.