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ELECTRICAL INSTALLATION
IRIG-B
GPS CONNECTION
OPTIONAL
AMPLITUDE MODULATED
SIGNAL CAN BE USED)
2–20
Correct polarity is also essential. The IEDs must be wired with all the positive (+) terminals
connected together and all the negative (–) terminals connected together. Each relay must
be daisy-chained to the next one. Avoid star or stub connected configurations. The last
device at each end of the daisy-chain should be terminated with a 120 ohm ¼ watt
resistor in series with a 1 nF capacitor across the positive and negative terminals.
Observing these guidelines will ensure a reliable communication system immune to
system transients.
IRIG-B is a standard time code format that allows time stamping of events to be
synchronized among connected devices within 1 millisecond. The IRIG time code formats
are serial, width-modulated codes which can be either DC level shift or amplitude
modulated (AM) form. The type of form is auto-detected by the relay. Third party
equipment is available for generating the IRIG-B signal; this equipment may use a GPS
satellite system to obtain the time reference so that devices at different geographic
locations can also be synchronized.
Figure 24: IRIG-B connection
GPS SATELLITE SYSTEM
IRIG-B
TIME CODE
GENERATOR
+
(DC SHIFT OR
–
RG58/59 COAXIAL CABLE
TO OTHER DEVICES
339 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 2: INSTALLATION
GE MULTILIN
339 RELAY
F1
IRIG-B(+)
RECEIVER
F2
IRIG-B(-)
896741.CDR
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