Polyphase electromagnetic transducer having a multipolar permanent magnet

An electromagnetic transducer comprising a stator and a rotor mounted to rotate relative to the stator, said rotor being adapted to spin around a rotation axis, defined by a positioning axle of such rotor, and including a multipolar permanent magnet which defines a rotor plane perpendicular to said rotation axis and is formed by a set of rotor pole pairs arranged in a circular manner about said rotation axis, the number of such rotor pole pairs being even and greater than two, each rotor pole pair having a magnetic axis oriented substantially along the direction of said rotation axis with a sense opposite to that of the adjacent pole pairs and defining an angle .alpha. in said rotor plane relative to said rotation axis the value of which is substantially equal to 360.degree. divided by said number of rotor pole pairs, and including N magnetic energization means respectively associated with N magnetic flux guidance branches, N being an integer greater than two, and comprising first and second principal stator parts, the first principal stator part defining N principal magnetic poles magnetically insulated from one another by zones of high magnetic reluctance and having a first superposition portion superposed onto said multipolar permanent magnet relative to a projection thereof in said rotor plane, each of such principal magnetic poles including at least one secondary magnetic pole, which is at least partially superposed onto said said multipolar permanent magnet relative to a projection thereof in said rotor plane, said secondary magnetic poles substantially defining a first stator plane parallel to said rotor plane, each secondary magnetic pole defining in said first stator plane an angle relative to said rotation axis the value of which is substantially equal to that of said angle .alpha., each secondary pole of each of said principal magnetic poles being angularly shifted relative to each secondary pole of each of the two adjacent principal magnetic poles and relative to said rotation axis by a deviation angle the value of which, modulo the value of said angle .alpha. is equal to said value of such angle .alpha. divided by N, said second principal part defining a magnetic return pole a second superposition portion of which is superposed onto said multipolar permanent magnet relative to a projection thereof in said rotor plane, such second superposition portion substantially defining a second stator plane parallel to said rotor plane, said first and second stator planes being located on either side of said rotor plane, each of said magnetic flux guidance branches having a first end magnetically coupled to a different said principal magnetic pole and a second end magnetically coupled to said return pole.