The second is reduced mechanical system stress. When the large
inrush current occurs, there are significant magnetic forces created
in the motor windings. These cause some parts of the winding to be
attracted to each other and to other parts repulsed. This mechanical
shock can damage the winding insulation leading to early failure.
The mechanical shock of the high torques produced with the large
starting current can cause failure of system elements such as
the motor shaft, belting, gear box, and drive train, and damage
to fragile product.