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What is the meaning of LSI Trip unit in Eaton MCCB?

In Eaton molded case breakers...

L = adjustable long delay pickup (LDPU) (a magnitude of current adjustment)

S = adjustable short delay pickup (SDPU) (a magnitude of current adjustment)

I = independently adjustable short delay time (delay time dial for delaying tripping on SDPU) (a magnitude of time adjustment)

In industry, generally, "I" would = adjustable instantaneous pickup (INST) (a magnitude of current adjustment) but,

in Eaton molded case breakers with LSI functionality, there is no "I " adjustment dial - we only have "I "as independently adjustable short delay time for changing tripping time on SDPU from as short as instantaneous (no intentional delay for tripping) to as long as the longest dial setting.