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
133
Temperature Behavior during Changing Operating States
For a better understanding of the above considerations several possible operating ranges in two different op-
erating areas will be discussed in the following paragraph. Settings indicated above are to be used prevaling 3
cold and 2 warm startup attempts have resulted in the restart limit reaching 66.7%.
A) Below the thermal restarting limit:
1. A normal startup brings the machine into a temperature range below the thermal restarting limit and the
machine is stopped. The stop launches the equilibrium time 4304 T Equal and generates the message
„66 TRIP“. The equilibrium time expires and the message „66 TRIP“ is cleared. During the time T
Equal the thermal replica remains "frozen" (see Figure 2-37, on the left).
2. A normal startup brings the machine into a temperature range below the thermal restarting limit, the
machine is stopped and is started by an emergency startup without waiting for the equilibrium time to
expire. The equilibrium time is reset, the thermal replica is released and „66 TRIP“ is reported as going
(see Figure 2-37, to the right).
Figure 2-37 Startups according to examples A.1 and A.2
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