For what it's worth, SKM does allow you to reduce the induction motor contribution to less than 5 cycles.
I don't see a problem being a little bit conservative with motor contribution:
- In some cases, the motor contribution makes devices trip faster. Here, the motor scenarios would be ignored.
- In the event that the motor contributes fault current without reducing trip time, then this would represent a higher energy condition.
In either case, the variability of utility fault current and the assumtions that we make to accurately model it, (80%, 60%, 40% etc) seem to have a much greater impact on study results than how we model the 5 cycles of induction motor contribution.
SKM only allows 10 scenarios. These end up consisting of up to 5 utility scenarios paired with motors/no motors. This takes the software long enough to calculate, I can't imagine trying to subdivide the motor modelling if we had 10 more scenarios to work with!