Electric motorcycle from Kravogl
The electric motorcycle from Kravogl is a form of a historical electric motor , which was developed and built by Johann Kravogl in 1867. Although the efficiency of this motor is around 15%, which was very high for comparable machines of the time, this design could not establish itself because of the low achievable power.
The rotor consists of a rotatable, ring-shaped cylinder ( torus ), in which a winding with several dozen taps distributed over the circumference, similar to a ring armature winding , is completely housed. The individual taps are led to the outside on a commutator . Inside the hollow ring there is a heavy soft iron body mounted on rollers with a length of approx. 1/3 of the circumference, which comes to rest in the lower area of the wheel when switched off due to gravity. When the supply voltage is connected, the commutator and the correspondingly connected taps on the individual windings exert a force on the soft iron body on the inside, which lifts it upwards. As a result of gravity, the soft iron body remains in a position dependent on the load and the rotatably mounted outer jacket begins to rotate. The cyclic switchover at the individual winding taps with the help of the commutator attached to the shaft ensures a permanent rotary movement of the jacket.
The higher the mechanical load on the motorcycle, the further the soft iron body on the inside is lifted upwards and when a certain vertex in the upper third is exceeded, the machine “goes out of step”. An increase in the weight (mass) of the soft iron body leads to problems due to friction and storage, which is why the performance of this type of construction is limited to around 7 W (approx. 0.01 PS).
A total of four engines of this type were built, of which Emperor Franz Josef bought one for the Polytechnic Institute in Vienna (today Vienna University of Technology) for 2000 guilders and awarded Johann Kravogl the gold cross of merit. This engine is owned by the Technical Museum in Vienna .
literature
- Johann Müller: Textbook of Physics and Meteorology . 8th, revised and enlarged edition. third volume, 1881, p. 517 ( online ).
Individual evidence
- ↑ L. Pfaundler: About the jacket ring machine from Kravogl and its relationship to the construction of improved dynamo-electric machines . In: Journal of the Electrotechnical Association in Vienna, 1st year . tape 1 . Vienna 1876, p. 141 to 145 .
- ↑ Johann Kravogl's motorcycle queried on March 28, 2012