Crank inductor
A crank inductor is an electrical generator that is operated by hand or feet . It is operated by turning a crank or a pedal drive (known as a pedal generator ).
Working principle
With the drive, a laminated iron armature is rotated around a horseshoe magnet in the device , on which a copper winding of about 4000 to 8000 turns is applied. As a result of the movement in the magnetic field , an alternating voltage is generated in the wire winding by electromagnetic induction . A spur gear ratio is installed between the crankshaft and armature shaft in order to achieve an armature speed that is sufficient for the generator to work at the desired frequency.
application
Crank inductors are used to generate test voltages, e.g. B. for the insulation measurement , in blasting machines to trigger explosions as well as in telecommunication technology :
A crank inductor is used in telephone sets in local battery operation to generate the ringing voltage . This ringing voltage causes a visual display ( indicator , signal lamp, drop flap on a flap cabinet ) or an alarm clock to respond to the remote station (exchange or other telephone) . Such a crank inductor supplies an alternating voltage of 30 to 100 V at a frequency of 15 to 25 Hz . The crank inductor with its alternating voltage is not suitable for the voltage supply for the actual call; a direct voltage source, the "local battery", is required for this near the telephone.
The technique was used by the Deutsche Bahn marshals until the end of the 20th century; crank inductors are still used today as block inductors for the field block, especially in mechanical interlockings . The protection against external voltages is a particular advantage here, as neither the direct voltage from the interlocking battery nor the mains alternating voltage can trigger incorrect blocking processes. In the military and disaster control ( THW , fire brigade , rescue services , etc. ), crank inductors are still used in simple field telephones .
literature
- Albert Palm: Electrical measuring devices and measuring devices. Springer Verlag, Berlin / Heidelberg 1963.
- Wilhelm Hille, Otto Schneider, Klaus Grossmann: Electrical expertise. Tape. 2, BG Teubner Verlag, Stuttgart 1991, ISBN 978-3-519-26806-2 .
- Ernst Hettwig, Walter Mai: Self-dialing long-distance traffic in railway telephone systems. 2nd edition, Springer Verlag, Berlin 1944.
- Wilhelm Lehmann: The electrical engineering and the electrical drives. Springer Verlag, Berlin / Heidelberg 1962.
- Paul Martin Pflier: Electrical measuring devices and measuring methods. Springer Verlag, Berlin / Heidelberg 1951.
Individual evidence
- ↑ Electricity simply made by yourself: Pedal generator creates energy through muscle power ( Memento of the original from July 10, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. - Article in Wohnen online from April 27, 2010 (accessed on: June 4, 2013).
Web links
- The crank inductor of the field telephone 33 (accessed on August 14, 2017)
- Telecommunications equipment crank inductor (accessed on August 14, 2017)