ZyXEL Communications PLA-470 V2 - V3.0.5 Przewodnik Instalacji Pobierz pdf (Strona 161)

Figure 7.24 illustrates the same principle but with two magnetic ferrites over a

three-phase network.

Choice of Injection Cable

It is preferable to inject the signal over the neutral cable for a single-phase network and on

one of the phases for a three-phase network. Better performance is achieved by injecting

the signal over a single cable than over several cables at the same time.

This method for connecting PLC devices requires access to the electrical wirings

of the 110 to 220V/50 to 60 Hz network, unlike capacitive coupling, which is

restricted to the connection of a device to an outlet. Therefore, it is important to

request a competent electrician to carry out the coupling operation that requires the

knowledge of the electrical hazards close to the cables and components of the electri-

cal network.

Figure 7.25 illustrates an Eichhoff PLC injector with the magnetic coil open

(on the left) and closed (in the middle) as it is around the electrical wiring, and the

F-type coaxial connector (on the right) used to connect the injector to the cable TV

modem.

142 Equipment

Figure 7.24 PLC signal injection by inductive coupling with two magnetic ferrites over a

three-phase network

Figure 7.25 Eichhoff PLC injector with coil and magnetic ferrites

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