Drive Questions

Two questions regarding sinamics s120 drive with sensorless vector control for ac induction motor
1) If i increase inertia of the motor, does speed acceleration will increase ? How can i find out what relation between motor inertia to speed acceleration ?

2) If i put proportioanl value for speed controller or current controller very inappropriate could it cause motor damage ?

Thank you.

These look like homework questions.

arocon said:

1) If i increase inertia of the motor, does speed acceleration will increase ? How can i find out what relation between motor inertia to speed acceleration ?

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This is more of a physics question than a drive question. if you increase the inertia will it require more or less power to accellerate?

arocon said:

2) If i put proportioanl value for speed controller or current controller very inappropriate could it cause motor damage ?

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Think about what effect increasing these gains might have? What is the consequence of setting any control loop gain too high?

Nick

I think it is mostly a drive question. The answer is that, within the torque and current limits of the motor/drive system, changing the inertia of the rotating machinery will not change the acceleration rate. When you program a specific accel/decel ramp into a VFD, it will force the motor to follow the ramp until either the torque or current limit is reached. At that point, either the drive will stop accelerating until the torque or current comes down or, if electronic shear pin action is active, the drive will fault and coast to a stop.