Thanks Loosemoose,
I got the similar answer from other resources.
Maximum Transient Current:
A short-lived oscillation/decay in a system caused by a sudden change of voltage or current expressed as a function of time exponentially. The universal time constant formula is given by-
Change= (Final-start)(1-e-t/τ)
ITransient = Imax (1- e-t/τ)
Where,
τ= L/R
e= eular’s number ≈ 2.7182818
e.g. t=1 sec , τ= 1
Itransient = Imax(1- e-1)= Imax* 0.6321 ≈ 0.5*Imax