Schweitzer Engineering Laboratories SEL-701, Instruction Manual

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Date Code 20010719
701 Motor Protection Relay
Event Analysis
Example Sequential Events Recorder (SER) Report
9.19
Table 9.7 Example Sequential Events Recorder (SER) Report Explanations
Table 9.7
Example Sequential Events
Recorder (SER) Event Report Explanations
Item # Explanation
13, 12, 11, 10, 9, 8 After a 10-second accelerating time, the motor relay indicates
the motor is running (11). Later, the current unbalance alarm
element (46UBA, aliased as UNBALNC_I_ALARM) times out,
causing the relay to close output contact OUT1, programmed to
indicate protection element alarms (9, 8).
7, 6 The current unbalance trip element (46UBT, aliased as
UNBALNC_I_TRIP) times out, causing the relay to trip. Since
now both ouput contact OUT1 and TRIP are asserted, the relay
places a ‘b’ in the T1 output column of the event report.
5, 4, 3 Declining current due to the opening contactor allows the
unbalance detecting overcurrent elements to drop out and the
relay deasserts output contact OUT1.
2, 1 As the current continues to drop, the relay declares the motor
stopped.