what is the starting......

The starting time is the time from the switching-on of the motor until having reached its stationary operation.

in which
J = total moment of inertia, to be accelerated, in kgm²
n = operating speed in r.p.m.
M_b= accelerating torque in Nm ( = Motor torque - Load torque)
The starting time tA is proportional to the total moment of inertia and inversely proportio­nal to the the accelerating torque.

The Motor torque and load torque curves verses speed in the same graph is necessary. Then you will have the accelerating torque for each value of speed from zero to the nominal speed and also average accelarating torque. By numerical calculation methods you can calculate the starting time more accurately.

Correct! Refer IEC 76 and calculate starting time. But foremost you need to have correct gd2 data of coupling and load.