Ice NP900 Series, Инструкция по применению

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Application Guide - NP900 Series 266 (504
)
A996A
Operating principle of the FSP function is to calculate in each start a equivalent start
stress given by the set starts per hour and safe stall time settings (hot and cold)
regardless of the actual start duration. In each start attempt time equivalent to safe stall
time is added to the starts counter which is then deduct by the safe stall time divided by
given starts time in hours. By this way the start counter can be applied so that it will follow
the motor thermal status and given starts per hours accurately.
Figure 3.3.4-131 FSP Starts counter update (picture is not in actual time-scale).
In the example above the motor is allowed four starts in given time (t), motor is started 4
times and the counter is updated accordingly. When only one start is left in the start
counter the FSP alarm is activated to note that only one start is allowed. After this start is
used, the restart inhibit is activated until the motor can be started again.
Cumulative start-up counter is updated constantly in each program cycle and the time for
inhibit/alarm and amount of used and available starts can be read from the IED. The
counter is updated in every start by safe stall time multiplied by nominal start-up current.
In each start the counter is increased by this product which is then in every cycle deduct
by starts/given time divided by program cycle time. By this way the start up counter can be
set precisely for each motor.