Figure. 5.4.18 - 98. Outputs in normal motor start, no speed switch.
The Ist> function should be set so that it takes into account the application's required starting time for a
normal motor start. The setting of the function should include a setting margin for the expected starting
time. If the starting of the motor is dependent on the process status (e.g. the motor's drive may have a
full load or have no load when started), the setting should afford it the longest possible starting time as
the status may affect the motor's starting time. If the start-up situation is supposed to always be the
same, a sufficient setting for the function's starting monitor would be the expected starting time with an
additional 10 % margin. During start-up the function monitors the accumulated
I
2
t value and when it
drops below the calculated
I
2
t value, the function allows the starting process continue.
If the starting of the motor takes longer than the function's set value, the function trips the breaker and
halts the starting process; if the motor cannot start normally there is something wrong with the
application.
A
AQ
Q-M257
-M257
Instruction manual
Version: 2.07
© Arcteq Relays Ltd
IM00021
191
Summary of Contents for AQ-M257
Page 1: ...AQ M257 Motor protection IED Instruction manual...
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