What Calculations are Possible with Below Specs when Selecting a MV Softstarter

You're going to need more information....application, location etc....Then you need to contact a few suppliers and ask for recommendations....

Addition, subtraction, multiplication, division to begin with.

Well, one ought to calculate more than a few phone calls to a few manufacturers of <...MV Softstarter...> equipment.

As Solar Eagle notes, you do not have enough information to safely apply a soft-start or reduced voltage starter for this motor. (Soft start defined as applying rated frequency at reduced voltage to motor, to reduce power system reactive demand / voltage dip, during acceleration, typically.)

You need to know the load accelerating time, usually Wk2, and you need to confirm the time that the motor rotor can withstand slip frequency operation, from motor designer. Significant slip frequency (rotor actual speed vs stator frequency) operation produces high amounts of heat in the motor rotor, assuming an induction motor, for instance. Motor overload relays are designed to protect stator windings, but not necessarily the rotor under unusual conditions, soft-start, for instance.

There is no standard for motors of this size in NEMA, for instance. There are design standards for up to 250HP 6 pole motors, so for designs outside this range, you need to confirm that the thermal duty imposed on the rotor during starting does not exceed the motor design. For the motor designer to answer this, you need the load inertia, and your planned starting voltage and/or current limit.

www.landbelectric.com/download-document/78-maximum-nema-inertia-starts.html