Page 14 - Application Guide Semiconductor Fuse Link

Occasional (non-repetitive) overload coeffi cient C
f3

Another overload condition to be considered is the single (non-repetitive) pulsed overload, or
«occasional» overload.
Such a situation occurs only a few times during the service life of a fuse, and would apply for
example when the fuse has to ride through a fault which is cleared by a downstream overcurrent
protection device.
The objective is to ensure that the peak element temperature is below a level which would cause
damage to the element notches.

In this case the allowable pulse current is signifi cantly higher than is the case for repetitive overloads,
and is given by

I1 Cf3 IMELT

The coeffi cient Cf3 is typically 0.75.

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