Motor Starting Time Calculator

Calculate the approximate starting time for asynchronous motors. Please review the notes towards the bottom of the page to understand the implications.

Motor Details

Rated Speed (RPM):

Inrush Torque (Nm):

Maximum Torque (Nm):

Motor Inertia (kg.m2):

per unit Voltage:

Mechanical Load Details

Load Type

Lift Fans Piston Pumps Flywheel

Load Torque (Nm):

Load Inertial (kg.m2):

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Motor Starting Time Calculation

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This Cacluation

The calculation uses the simplified method given in our site post 'How to Calculate Motor Starting Time' to determine the approximate starting time.

Tips:

per unit voltage: this setting allows for reduced voltage starting scenarios.  For for direct online starting the motor would be operated at full voltage (per unit voltage =1).  For star-delta the voltage during starting would be 1/√3 of the normal running voltage  (per unit voltage = 0.577).  Similar situation for other starting methods.