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Motor Acceleration Time


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Hi Sujit welcome to the forum. The acceleration time is a funtion of the load on the motor as well as the starter type. Unfortunatly there is no simple formula that can calculate every potential combination of load and starter type. If you provide a litle more detail we may be able to help.
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Hello Sujit


The acceleration rate of a motor, is a function of the total inertia being accelerated by the motor, and the acceleration torque of the motor.

The acceleration torque at any speed, is the difference between the torque produced by the motor at that speed, and the load torque at that speed.

You can plot the load speed torque curve, and the motor speed torque curve (at the starting voltage or current used) and take the difference between the two curves to get the acceleration torque at that speed.


Have a look at the Electrical Calculations software at http://www.LMPhotonics.com You can calculate and graph the acceleration of motors and loads. If the load inertia is low, the acceleration is fast. If the load inertia is high, the acceleration is slow.


Motors have a maximum acceleration time. This is related to the energy that is dissipated in the rotor during start, not a measure of the rate of acceleration. When the motor is starting, there is high slip energy dissipated in the rotor of the motor. The total dissipation is equal to the full speed kinetic energy of the load. Different motors have different abilities to absorb the kinetic energy of the load.

Maximum start times vary between 10 seconds and 40 seconds under DOL conditions.


Best regards,


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