Functions
2.7 Motor Protection (Motor Starting Protection 48, Motor Restart Inhibit 66, Load Jam Protection)
SIPROTEC, 7SK80, Manual
E50417-G1140-C344-A4, Release date 08.2010
139
Example:
Motor with the following data:
The setting for address 4402 Load Jam I> as secondary value is calculated as follows:
The tripping delay time can remain at the default setting of 1 s. The warning threshold is set to 75% of the trip-
ping element (4404 I Alarm ≡ 0.95 A sec.).
The tripping delay time can remain at the default setting of 2 s.
In order to block the function during motor startup, the parameter 4406 T Start Blk. is set to double startup
time (T Start Blk. = 2 · 8.5 s = 17 s).
2.7.4 Motor (Motor Starting Protection 48, Motor Restart Inhibit 66, Load Jam
Protection)
Functions relevant to Motor Protection and Restart Inhibit for Motors and Load Jam Protection are described
in the aforegoing two sections and contain information concerning configuration.
2.7.4.1 Settings
The table indicates region-specific default settings. Column C (configuration) indicates the corresponding sec-
ondary nominal current of the current transformer.
Nominal voltage V
Nom
= 6600 V
Nominal current I
Nom
= 126 A
Long-term current rating I
max
= 135 A
Startup duration T
startmax.
= 8.5 s
Current transformer I
NomCTprim
/ I
NomCTsec
= 200 A / 1 A
Addr. Parameter C Setting Options Default Setting Comments
4101 FCT 48 OFF
ON
OFF 48 Startup Time Supervi-
sion for Motors
4102 STARTUP CURRENT 1A 0.50 .. 16.00 A 5.00 A Startup Current
5A 2.50 .. 80.00 A 25.00 A
4103 STARTUP TIME 1.0 .. 180.0 sec 10.0 sec Startup Time
4104 LOCK ROTOR TIME 0.5 .. 180.0 sec; ∞ 2.0 sec Permissible Locked Rotor
Time
4105 STARTUP T WARM 0.5 .. 180.0 sec; ∞ 10.0 sec Startup Time for warm
motor
4106 TEMP.COLD MOTOR 0 .. 80 %; ∞ 25 % Temperature limit for cold
motor
4301 FCT 66 OFF
ON
OFF 66 Startup Counter for
Motors
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