Nautel XR3-PREINST, Руководство по предварительной установке

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XR6/XR3 Pre-installation Manual Electrical requirements
Issue 3.0 2009-07-15 Page 5-3
A surge protector panel containing suitably rated varistors is available from Nautel. Install the surge
protector panel close to the station reference ground, and as close as possible to the ac service
entrance.
The ac power source usually has the lowest impedance path to ground during a lightning strike and
normally carries most of the lightning-induced current away from the transmitter site. When lightning
hits the power source (for example, striking a transmission line near the transmitter site), a significant
induced current may flow towards the transmitter. The goal of lightning protection is to route the
current around the transmitter to the best available ground.
For detailed information about surge protectors and lightning protection, refer to the Nautel Site
Protection Manual.
Recommended configuration for three-phase ac power source.
Use a 4-wire Wye (star)
configuration, with the three phases balanced to ground.
Wiring
Table 5.3 on page 5-4 shows the wiring recommendations for each ac voltage, and identifies the wire
gauges that are specified for worst case conditions. Smaller gauges may be used when actual
conditions related to transmitter power and wiring allow it. A certified electrician should be consulted
to ensure that all wiring meets local electrical code requirements.
CAUTION:
For three-phase applications do NOT use open delta ac power sources that
use two identical transformers. These systems are susceptible to third
harmonic distortion and line transients, and may cause peak voltages to
exceed the line voltage. This can cause increased power supply noise or
even component failure (for example, rectifier failure).
CAUTION:
Table 5.3 on page 5-4 is based on recommendations by the Canadian
Electrical Code. Local codes may vary.