Siemens SIPROTEC 7SJ531 - Page 68

-ETHOD OF OPERATION3*
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3TART UP CRITERION IS A SETTABLE CURRENT THRESHOLD
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$%4 WHEN THIS LIMIT IS EXCEEDED THE TIMER
ACCORDING THE ABOVE FORMULA IS RELEASED
4HE DEFINITE TIME STAGE OPERATES WHEN THE ROTOR IS
LOCKED 7HEN THE START
UP PERIOD OF THE MOTOR LASTS
LONGER THAN THE MAXIMUM PERMISSIBLE LOCKED ROTOR
TIME TRIP IS EFFECTED PROVIDED THE LOCKED ROTOR INPUT
OF THE RELAY IS ENERGIZED FROM AN EXTERNAL SPEED
MONITOR 3TART
UP CRITERION IS AGAIN THE THRESHOLD
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&IGURE  SHOWS THE LOGIC DIAGRAM OF THE START
UP
TIME MONITORING
3TART UP TIME MONIT OFF
2OTOR LOCKED
ANNUNCIATION
4RIP
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2OTOR LOCKED
3424
350 BLK
OFF
34!24 3506
31
2
3424
350 OFF
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3424 350 TRIP
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2ESET MEASUREMENT
3424 350 PU
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43424 350
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&UNCTION NUMBER
"LOCK START
UP TIME MONIT
3TART
UP TIME MONIT ON
3424 350 ACT
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&REQUENCY OUTSIDE
OF WORKING RANGE
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ON
&IGURE  ,OGIC DIAGRAM OF START UP TIME MONITORING
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