Actions to increase the cogging torque and effects of the increased cogging torque to permanent magnet DC motors

In this paper the cogging torque of an existing permanent magnet DC motor must be increased. Thus motors are frequently used in motor vehicles. In order to hold a position the motor must be under current, because in most cases the cogging torque is too small to keep the motor in position. The possibilities to decrease cogging torques are well known. Consequently in this case these facts become valid too, but the start and end of the design process is noticeable different. Therefore all steps to increase the cogging torque is checked by basic theory. But this doesn´t say that the problem is described by analytic methods. In contrast the finite element program ANSYSreg is a basic tool of this paper. The cogging torque is calculated by means of co-energy and not by the Maxwell stress tensor. The reasons are explained in this paper too