| 摘要 |
The invention relates to a small electric motor or generator which is suitable especially as a dynamo for cycles and has a disc-shaped rotor (2) with axially magnetised poles on the ends which consist of permanent-magnet material, which rotor (2) is supported such that it can rotate with the rotor shaft (3) opposite at least one coaxially arranged coil system (4, 4a, 4b). The coil system consists of a pot-shaped iron return path (7) having pole tongues (8) at the ends which are directed radially against the rotor shaft (3), and having an annular coil (9) arranged therein. The annular coil (9) is a single cylindrical coil which occupies the space between the ends of the iron return path (7). This results in simpler production of such small motors or generators and an improved electrical efficiency is also achieved which is especially important for use as a cycle dynamo since excessively high mechanical losses for specific required light power must be accepted in the case of known dynamos. <IMAGE>
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