# Negative magnetic periodicity

Machines with concentrated windings and a negative magnetic periodicity can be simulated much faster due to the fact that the simulated cross-section can be cut in half.

Figures 1a and 1b show negative periodicity for integer-slot windings. A negative periodicity actually doubles the number of winding symmetries, and cuts the cross-section of the machine that has to be simulated in half when applying odd periodic boundary conditions. Negative periodicities are also common for concentrated windings with an even number of stator slots, such as the 12 slots, 10 poles windings shown in Figures 1c and 1d. These is good news with approximately four times faster simulations for load simulations with the concerned winding layouts.

Fig. 1 Winding examples with 12 slots and negative periodicity: a) 2 poles, single layer, b) 2 poles, double layer, c) 10 poles, single layer, d) 10 poles, double layer.