maxon DC motor maxonmotorusa（maxon直流电机 maxonmotorusa）.pdf

maxon DC motor Permanent magnet DC motor with coreless winding This presentation shows the design and operation principle of the maxon DC motor. These are small DC motors with permanent magnets and winding without iron core. • In a first part we present the differences to the conventional DC motor with iron core and the advantages of such a coreless design. • The second part treats the magnetic circuit in the stator and some of the characteristics of the permanent magnets in use. • In the third part we have a closer look at the coreless winding and the current flow. • Then we investigate the interaction between current and magnetic field and the influencing parameters. • In the fifth part we present the commutation process and the different properties of graphite and precious metal brushes. • At the end some remarks about service life and bearings. © 2012, maxon motor ag, /academy Page 1 maxon DC motor Permanent magnet DC motor with coreless winding Low power conventional DC motors (below approx. 1 kW) mostly use permanent magnets to produce the stator magnetic field. The winding is on the rotor side. Its wound around an slotted iron core for flow concentration and enhancement. DC motors with ironless winding dont use the iron core. Thats the system maxon uses and which is to be presented here in more detail. © 2012, maxon motor ag, /academy Page 2 maxon DC motor Permanent magnet DC motor with coreless winding Lets have a look at a conventional DC motor. There are three main subassemblies • The stator with the permanent magnet segments at the periphery, the housing that serves for guiding the magnetic flux, and the mounting flange. • The rotor with winding and iron core that are mounted on the shaft. The shaft itself is supported in the stator by sleeve bearings or ball bearings. On the rotor there is also the