## Permissible inertia for Brother gearmotors

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Joined: Thu Dec 29, 2016 10:19 am

### Permissible inertia for Brother gearmotors

Q: I am considering using a Brother motor(G3F40N10-MV9AWN) to rotate a 5-kg drum mounted vertically. The drum has a diameter of 1000mm. The speed and torque characteristics of the motor meets my application needs just fine. I am unsure if the load inertia would exceed the specifications. How do I find the permissible inertia for Brother gearmotors?

A: The permissible rotor inertia for our Brother gearmotors is shown below under Allowable Inertia moment (IA) for motors with different output power (kW):

Brother Permissible Inertia Table.JPG (62.14 KiB) Viewed 563 times

The output power ratings can be converted as below:

1HP=0.7457 kW

The permissible inertia for the motor with gearheads can be calculated as below:

Equations for gearhead permissible inertia.JPG (18.83 KiB) Viewed 563 times

When selecting an AC motor, the load inertia should be calculated and the selected motor’s permissible inertia should exceed the load inertia for instant start/stop operations. If the load inertia exceeds the permissible inertia, the acceleration/deceleration time for the motor should be calculated accordingly to prevent the motor from stalling.

Calculation example:

Permissible inertia for G3F40N10-MV9AWN

Sample calculation.JPG (28.18 KiB) Viewed 548 times

The permissible inertia for G3F40N10-MV9AWN exceeds the load inertia of the drum application, which means instant start/stop is allowed for the motor.

More information about the allowable inertia of Brother motor is shown in the attachment below. Please let us know if you have any additional questions!
Attachments
Mid Series Allowable Inertia Moment of Motor Shaft (J= (GD^2)4).pdf