| 摘要 |
The invention concerns revolving field motors with fractional slot winding, which are excited by permanent magnets. A problem associated with these electric motors is a high stopping torque which is undesirable in particular when the current-free motor is racing due to an external torque. To solve this problem, it is proposed that the stopping torque of each individual permanent magnet (5, 6) is symmetrical within each half division (b), defined as the angular distance between the median planes of a ridge (2) and an adjacent groove (3) of the stator (1), about the median plane of the half division (b), and that an odd number of supernumerary or subnumerary grooves is present. In a proposed complement or alternative, the number of permanent magnets (5, 6) chosen has no common factor with the number of supernumerary or subnumerary grooves. Possible fields of application are all drives with revolving field motors excited by permanent magnets. |
