4.2.5
Delayed Protection Enabling During Motor Starts
When the EMR-3MP0 detects a motor start, various timers are started. Each of these
timers blocks a protective function until the set delay expires. (See
way false trip decisions by these protection functions during the motor start are
prevented.
MotorStart_E95
Module input state: External blocking (during the motor start phase)
MStart . Start
t
0
MStart .
t-Blo-IOC
56
MStart . IOCStartBlock
t
0
MStart .
t-Blo-GOC
56
MStart . GOCStartBlock
t
0
MStart .
t-Blo-UnderLoad
56
MStart . ULoadStartBlock
t
0
MStart .
t-Blo-IUnbalance
56
MStart . UnbalStartBlock
t
0
MStart .
t-Blo-JAM
56
MStart . JamStartBlock
The setting parameters for all these start delays are available within the menu [Protection
Para / MStart / Start Delay Timer].
• IOC (Instantaneous overcurrent):
The setting »t-Blo-IOC« defines the time (in seconds) after a start is recognized until
the IOC trip and alarm functions are enabled. Use this delay to inhibit IOC tripping on
a current peak caused by magnetic inrush when the motor is first energized (usually
two to three cycles).
• GOC (Ground fault):
The setting »t-Blo-GOC« defines the time (in seconds) after a start is recognized until
the »50X[x]« protection modules are enabled.
• UnderLoad:
The setting »t-Blo-UnderLoad« defines the time (in seconds) after a start is
recognized until the »37[x]« protection modules (ANSI 37 underload functions) are
enabled.
• IUnbalance (Current unbalance):
The setting »t-Blo-IUnbalance« defines the time (in seconds) after a start is
recognized until the »51Q[x]« protection modules (ANSI 46 current unbalance
functions) are enabled.
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EMR-3MP0
4 Protective Elements
4.2 Motor Starting and Control Module