What good is N plus 1 redundancy with a UPS?

Answer 1

The basic idea of fault tolerance through redundancy is to size the system so that there is at least one more unit than the minimum required to carry the load. Thus, if a load is 10 amperes, a fault tolerant redundant system might have three (3) 5 ampere units in parallel;one more than is needed, hence: N+1 redundancy. The failure of any one power module leaves sufficient power available to support the whole load.