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I have built a simulation model for a permanent magnet DC motor, but I am having trouble accepting the results.

dynamic equation states. machine accelerates as long as there is torque imbalance between elctrical and load torque, below.

dw/dt = (1/J)*(Telectrical - Tload - Tfriction)

I get acceleration of about 1140 rads/s^2 , which is crazy, even when the motor is loaded 100%.

So the only thing comes to my mind is: does the rotor inertia (J) change with the loading of motor? if so, how would I work it out?

Thanks in advance

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# DC motor question

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