Pilot Wire

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  3A20 Pilot Wire Intertrip Send & Receive Relays

  The operating element of the 3A20 Series is based on the well proven 6R heavy duty attracted armature control relay. The DC version of this relay is inherently immune to AC voltages & the addition of an AC filter circuit & copper shield over the core of the receive relay greatly enhances this attribute while maintaining high sensitivity to DC voltages. A mechanical flag indicator is provided on both the…
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  3A300 Pilot Wire DC Intertrip System

  The 3A300 has been designed to integrate a complete scheme allowing bi-directional group intertripping of up to four remotely connected sites. Inherent 5KV or 15KV isolation allows application on electrical networks where large induced voltages may be experienced on the pilots. System reliability is provided by the extensive built in supervision facilities. Security is achieved through the high isolation & AC immunity of the intertrip receive elements. The efficient compact…
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  3A400 Pilot Wire Supervision System

  The 3A400 concept is based on the need to improve the performance of existing pilot wire protection schemes by increasing reliability & availability as well as adding an over current guard function. With the 3A400 this can be achieved at considerably lower cost than the replacement of the existing proven protection relays & change over to a fibre optic communication channel. A revised protection scheme using the 3A400 comprises the…