Control technology

KZR-4S Short-Circuit Relay

The KZR-4S Short-Circuit Relay monitors the current in three-phase networks. It is equipped with 2 limit value relays, whose response values can be set independently of each other, ranging from 0.2 A to 20 A for the 5A variant and from 0.04 A to 4 A for the 1A variant.

Each limit value has its own adjustable time delay. The switching behavior of the limit value relays can be selected as closed or open ( normally energised or normally de-energised ), and set for over- or undercurrent detection.
Current is measured via current transformers. The current measurement circuits are galvanically separated from each other and from the measurement electronics. Suitable current transformers are to be provided for adapting to the measurement circuits. The auxiliary voltage and release input are galvanically separated from the measurement circuits.

Special feature: The threshold relay 1 can operate as a current-depended delayed overload relay. This behaviour is modelled on the thermal - temporal overload triggering of motor circuit breakers. The KZR-4S meets the VDE 0108 requirement with 110 % nominal current within a 12-hour interval. This current-dependent overload trigger can be switched off, resp. combined.
Use the current version of the downloadable parameterisation software for setting the device parameters.

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