The influence of the third deviation of way above time on the design of Electrical Machines

There are more and more demands to reduce jerks in electrical drives. This is derived from the wish to reduce mechanical stresses according to peak-torques. The consideration of the dynamic motion gives equations for way, speed, acceleration and jerk. The last one is the third deviation of way above time. The reduction of jerks demands to change the acceleration. On the other hand the run-up time must not be increased. Therefore there must be a change of the maximum acceleration occurring during the run-up period. Thus it can be shown that according to the jerk-free motion the maximum value of acceleration must be greater. When designing the motor this is to be taken into account. That means the maximum torque/thrust of the motor becomes greater. The motor size is bigger. Thus we have now besides the well known influence of the temperature-rise a second quantity influencing the motor design