Outrunner
An external rotor is a type of rotating electrical machine in which the stationary part ( stator ) of the machine is inside and is enclosed by the moving part ( rotor , "rotor" ). The machine can be used as an electric generator or as an electric motor , depending on the operating point and design . Typical representatives of asynchronous motors with squirrel cage rotors are axial fans , ceiling fans, centrifugal motors and other applications in which the rotor's moment of inertia does not play a role or is even desirable.
Emil Ziehl designed the first external rotor motor for Berliner Maschinenbau AG in 1897 . The US patent was granted in 1900, the German patent in 1904.
In the electronically commutated direct current motors , which are often designed as external rotors, the rotor consists of several alternately radially aligned permanent magnets arranged in a ring or a correspondingly multi-pole magnetized ring. These include, for example:
- Role dynamos , gearless hub dynamos and hub motors ( direct drive )
- Magnetic ignition and alternator on some motorcycles, also flywheel
- Direct drive of floppy disk drives as well as the head drum and the capstan of video recorders
- Direct drive of the polygon mirror of the scanner unit of laser printers
- Axial fan for direct voltage
literature
- Gregor D. Häberle, Heinz O. Häberle: Transformers and electrical machines in power engineering systems . 2nd Edition. Europa-Lehrmittel, Haan-Gruiten 1990, ISBN 3-8085-5002-3 .
Web links
Individual evidence
- ↑ External rotor motor chronicle . Ziehl-Abegg , 11/1999, p. 3.
- ↑ http://www.google.com/patents/US662484