IRP=34 Alternative Stone 3-phase

IRP = 34 same as IRP = 32, except that

krg=1[Sn+SlSlr1Slr]n{k_{rg}} = 1 - {\left[ {\frac{{{S_n} + {S_l} - {S_{lr}}}}{{1 - {S_{lr}}}}} \right]^n}