pairs of the rotor is pr 10 the number of externally effective pole pairs in this case corresponds to the number of pole pairs of the rotor the numbers of pole pairs of the electric machine 1 can generally be combined according to the following formula fig2 shows the electric machine 1 according to fig1 in longitudinal section it can be seen here that the rotor 7 is so designed as to be pot shaped the pot shaped rotor 7 is connected to a shaft 13 in a non rotatable manner a housing 14 of the electric machine can also be seen in fig2 the housing 14 has a first flange 15 on the drive side the housing 14 has a second flange 16 on the non drive side a first bearing 17 is arranged between the first flange 15 and the shaft 13 and is designed as e g a ball bearing the electric machine 1 also has a supporting element 18 on which the inner stator 10 is held a second bearing element 19 is arranged between the supporting element 18 and the rotor 7 and can likewise be designed as a ball bearing fig3 shows a further embodiment variant of an electric machine 1 in cross section the electric machine 1 represented in fig3 differs from that in fig1 in that the electric machine 1 has a first cooling device 20 for cooling the inner stator 10 the first cooling device 20 comprises a plurality of cooling tubes 21 which are arranged within the iron core assembly 11 of the inner stator 12 the cooling tubes 21 are uniformly arranged in a circumferential direction of the inner stator 12 the cooling tubes 21.