Calculation using change-over frequency
Frequent starting of motors is called switching mode and the maximum changeover frequency per hour must be checked. The manufacturer's data usually show
the allowable no-load switching per hour, i.e., the number of change-overs at
which the motor reaches its maximum temperature without load and without an
additional flywheel moment during idle operation. The frequency of changeover plays an important role in operating mode S4.
The allowable frequency of change-over of a motor is determined by its temperature limit. It is derived from the square mean value of current from the cycle
characteristic. This mean value may not exceed the rated current of the
machine.