6–142 350 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
S5 INPUTS/OUTPUTS CHAPTER 6: SETPOINTS
Critical Failure Relay
#7
The 350 relay is also equipped with one output relay (# 7 - “Critical Failure Relay”) for fail-
safe indication. There are no user-programmable setpoints associated with this output
relay. The logic for this relay is shown below.
The Critical Failure Relay (Output Relay 7) is a form C contact (refer to the Typical Wiring
Diagram) with one NO and one NC contacts (no control power). Output relay 7 is energized
or de-energized (state change) depending on the following conditions:
1. Output Relay 7 will be de-energized, if the relay is not IN-SERVICE or the control power
is not applied to the relay
2. Output Relay 7 will be energized when the control power is applied to the relay and
the relay is IN-SERVICE mode.
3. Output Relay 7 will stay de-energized, when the control power is applied, if the relay
was not programmed as “Ready”, or upon major self-test failure during relay boot up.
4. Output Relay 7 will change state from energized to de-energized if the 350 relay
experiences any major self-test failure.
Courtesy of NationalSwitchgear.com
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