2-12
MIGII Digital Protection for Electrical Machines
GEK-113188A
2.9 LOCKED ROTOR (48)(MIGII Q)
2 PRODUCT DESCRIPTION
2
2.9LOCKED ROTOR (48)(MIGII Q)
After a motor start, once the magnitude of any of either phases A, B or C exceeds the pickup level (1.01 to 10 xFLC) for a
period of time specified by setting, a trip will occur. This feature may be used to indicate a stall condition when running. Not
only does it protect the motor by taking it off line quicker than the thermal model (overload curve), it may also prevent or
limit damage to the driven equipment that may occur if motor starting torque persists on jammed or broken equipment.
The pickup level should be set higher than the motor loading during normal operations but lower than the motor stall level.
Normally the delay would be set to the minimum time delay, or set such that no nuisance trips occur due to momentary load
fluctuations.
A setting to block the element after a motor start is included, avoiding set pickup levels higher than the motor starting
current.
Summary of Contents for Multilin MIGII
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