Application Guide - NP900 Series
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A996A
Figure 3.3.4-132 FSP Starts counter update when thermal hot and cold status is
considered.
If the motor thermal load is monitored, the available starts can be updated on-line in the
IED and the precise follow up of the motor status can be monitored and correct amount of
starts can be allowed for the motor. In the figure above the motor is allowed for 4 starts
when it is cold, while 3 starts are allowed when the motor is hot. In the figure described
situation motor is started 3 times when it is cold and the hot limit is reached before the
motor is started 4
th
time. Now the motor was allowed for 4 cold and 3 hot starts and due to
the 3 cold starts the counter accumulated used starts amount allows only 1 start to be
done due to motor has been started previously already 3 times when cold. When the
motor in this situation is started again while the thermal status is “hot” the restarts inhibit is
activated and the start cooling time is counted according to hot starts reduction rate. If the
motor would be stopped now and the thermal load would let to count under the “hot” limit
the starts reduction would be counted according to “cold” motor status.
