-ETHOD OF OPERATION3*
6
#
' #
5NBALANCED LOAD
PROTECTION OFF
OFF
) PROTECTION
)
,
)
,
)
,
)
)
)
4 )
) 4RIP
) &AULT
) &AULT
4 )
NEGATIVE SEQ
2EVERSED PHASE ROTATION
"LOCK UNBALANCED
LOAD PROTECTION
&.O
&.O
&.O
&.O
31
2
ON
ANNUNCIATION
) BLOCKED
4RIP
) OFF
F
&REQUENCY OUTSIDE
OF WORKING RANGE
) ACTIVE
&.O
&.O
&.O
&UNCTION NUMBER
5NBALANCED LOAD
PROTECTION ON
&IGURE ,OGIC DIAGRAM OF THE UNBALANCED LOAD PROTECTION
3TART UP TIME MONITORING FOR MOTORS
4HE START UP TIME MONITOR PREVENTS THE MOTOR FROM
DAMAGE CAUSED BY EXCESSIVELY LONG START
UP OC
CURRENCES 4HESE MAY HAPPEN WHEN FOR EXAMPLE
THE ROTOR IS LOCKED THE DRIVING TORQUE IS TO HIGH OR
IMPERMISSIBLE VOLTAGE BREAK DOWN OCCURS -A
CHINES WITH THERMALLY CRITICAL ROTOR MAY BE STRESSED
UP TO THEIR THERMAL LIMITS WHEN THEY ARE STARTED SEVER
AL TIMES
4HE START
UP TIME MONITOR PROVIDES A DEFINITE TIME
STAGE AND A CURRENT DEPENDENT INVERSE TIME STAGE
4HE INVERSE TIME STAGE OPERATES NORMALLY WHEN THE
ROTOR IS NOT LOCKED BUT THE RUN
UP PERIOD OF THE MO
TOR IS PROLONGED BY REDUCED VOLTAGE AND CONSE
QUENTLY DECREASED CURRENT 4HE TRIP TIME OF THIS
STAGE RESULTS FROM THE FORMULA
T
)
3424-!8
)
4
3424-!8
FOR ) )
3424
$%4
WHERE
T
TRIPPING TIME
)
ACTUAL CURRENT RMS
)
3424 -!8
PARAMETERIZED START UP CURRENT
)
3424 $%4
PARAMETERIZED PICK UP THRESHOLD FOR
START
UP DETECTION
4
3424 -!8
PARAMETERIZED START UP TIME
ONLY FOR MODEL 3*J JJJJ JJJJ
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