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How are the Long Time, Short Time, Instantaneous, and Ground-fault pickup levels determined on a Micrologic trip unit?

Issue:
How to set dials on trip unit? What do the dials mean?

Product Line:
Circuit Breakers

Environment:
Applies to micrologic trip unit with Long Time, Short Time, Instantaneous, and Ground Fault on their trip unit.

Cause:
Inquires on how to set trip unit up? What the dials mean?  How are the settings determined?

Resolution:
The settings are determined by a coordination study.

Description of what the dial settings mean:

The Long Time (current rating) (Ir ) is the long-time pickup setting multiplied by the sensor plug amperage (In ).
The short-time current (Isd ) equals the short-time pickup setting multiplied by the long-time pickup (Ir ).
The instantaneous current pickup amperage (Ii ) is equal to the instantaneous pickup setting multiplied by the sensor plug amperage (In ).
Ground-fault pickup values (Ig ) is equal to the ground-fault pickup setting multiplied by the sensor plug amperage (In ).


CTA-ID : 7989
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