Starting Torque for 3 Phase Induction Motor

Dear all

Attached are the performance Curves for 3 Phase Squirrel Cage Induction Motor (2 Pole, 2967 RPM 50 Hz). The Motor is used to drive Centrifugal Compressor Train through Gear Box. As per attached Motor Torque Speed Curves, Motor can develop Peak Torque equal to 2.5 times Full Load Torque which seems to be well above the Mechanical Load (Inertia of Compressor Train and Load due to Gas Flow and Pressure)

Being from Mechanical background looking at the curves, I am unable to understand if the Actual Peak Torque developed by Motor during startup is equal to 2.5 times the Full Load Torque or this is just a value indicating what Motor is capable of delivering and actual Peak Torque developed will jus match the load Curve at the bottom ?
The curves are necessary, but you lack other information, such as:
a) Inertia of motor !
b) Inertia of compressor !
c) Gear box Ratio !
If you are interested I will provide you with an example of the procedure to use...
Regards, Phil Corso