clarity on contactor ratings for type-2 Co-ordination between Fuse less selection & fuse protected selection.

hi folks!
Enclosed herewith Siemens Type-2 co-ordination table for Fuseless & fuse protected selection for IE-2 motor.
why contactor ratings are different when used with breakers & fuses.
e.g. For 75 kW 415V IE2 Motor
Fuse less : Line & Delta contactor ratings : 150 A & Star: 65A
Fuse protected : Line & Delta contactor ratings : 80 A & Star: 65A

can anybody elaborate on this.




A fuse is faster to react than a circuit breaker under fault conditions, this reduces the amount of let through energy so less damage is done to the contactor. This is why a smaller contactor can be used with fuses for type 2 co-ordination. Using fuses will save you money in an initial design but you need to make sure you keep spare fuses.