Emil Stöhrer

Emil Stöhrer

Emil Stöhrer (born September 25, 1813 in Delitzsch near Leipzig ; † August 25, 1890 in Leipzig) was a German mechanic , electrical engineer and inventor of electric generators , electric motors , an electric car , electric telegraphs and musical instruments .

Life

Emil Stöhrer was born as the son of a doctor in Delitzsch in 1813, in the year of the victorious Battle of the Nations near Leipzig against Napoleon for the liberation of Europe. He received a school education up to the Abitur exams , which he completed from 1827 to 1829 in the Princely and State School Schulpforta . Then he began his apprenticeship with the well-known Leipzig university mechanic Johann Gottlieb Wießner , who was very well known for his scientific instruments.

After this technical training, he went on a hike to acquire practical skills, which led him to Paris, the then stronghold of precision mechanics and electromechanics. Ampere was also effective here, on which the distinction between current strength and voltage as well as the verification of electrodynamic current effects go back. This environment also gave rise to suggestions that later prompted Stöhrer to build electromagnetic devices, which he advanced to become the leading manufacturer in Germany. His wandering ended with the establishment of his own workshop in Jena .

Eventually he married a daughter of his former teacher Wießner and at the same time entered the workshop of his father-in-law at Weststraße 88 (today Friedrich-Ebert-Straße) in Leipzig, which he continued to run alone from 1842 after his death. After more than 20 years, he handed the business over to his son Emil Stöhrer (born March 1, 1840 in Leipzig) in 1863. He himself then founded a second workshop for electrotherapeutic devices in Dresden and also handed it over to his son Emil in 1880 after more than 15 years. After his unexpected death in 1882, he took over both businesses himself.

Professional Activities

Stöhrer's professional activity in the field of electrical engineering coincides with a period of physical-theoretical forerunner, combined with close cooperation between theoretical and experimental physicists with experienced mechanics and business people interested in business. As a prerequisite for the strong development of electrical engineering during this time, the outstanding work results are to be seen, as these were achieved in particular by Gustav Theodor Fechner (1801–1887), Carl Friedrich Gauß (1777–1855), Wilhelm Eduard Weber (1804–1891), Michael Faraday (1791–1867), Emil Lenz (1804–1865) and subsequently through James Clerk Maxwell's (1831–1879) complete presentation of the electromagnetic field and light theory .

In this environment, Stöhrer initially created widely applicable electric batteries and induction devices. He was one of the first to build electric generators and electric motors with relatively strong currents, which aroused the interest of his contemporaries in an economic use. He himself also used electromagnetism to drive an electric car , with which he drove from the city center to the Leipzig suburb of Connewitz , about 5 km away, in 1842 , and for which he also had a patent.

In 1844 he improved his electro-magnetic machines by arranging several permanent magnets (horseshoe magnets) in a circle and juxtaposing them with just as many electro-magnets that were rotatably attached to a common axis. This "Stöhrer'sche machine" has long been considered the most suitable of its kind throughout Germany and has been used in a variety of practical applications.

In 1846 Stöhrer developed an electrical pointer telegraph that was operated with alternating current from a magnetic inductor. He was encouraged to do this by Weber, who had been appointed to the physics chair at the University of Leipzig as the successor to Fechner and who had already worked with Gauss in Göttingen on electromagnetic telegraphs. With the pointer telegraph from Stöhrer, the letters and other characters were arranged in a circle on a disc and could be selected with the help of a pointer, which was shifted by equal amounts on the transmitter and receiver side according to the transmitted current pulses, thus transmitting the individual characters one after the other.

This pointer telegraph was used from 1847 on the Saxon-Bavarian State Railway on the Leipzig-Hof line, whose terminal station has been preserved in Leipzig to this day and has since been connected to the main station by the city ​​tunnel . When the aim was to modernize the Bremen – Bremerhaven electrical telegraph line from 1846 in 1849 , the letter telegraph by Emil Stöhrer from Leipzig was also tested, but the Morse system was then awarded the contract for the transmitting and receiving devices .

Stöhrer also dealt with the construction of musical instruments , in particular a pianino with harmonium and a highly original string instrument in piano shape with keyboard , which could replace a full string orchestra and which at exhibitions in Paris and Vienna as the most perfect of its kind was praised.

Stöhrer was thus a historical personality who combined technical skills and experience with scientific methodology, which resulted from direct collaboration with physicists such as Wilhelm Eduard Weber, and with the economic interests of a manufacturing businessman to create an engineering-based way of working.

Honors

• Stöhrer was vice president of the Leipzig Polytechnic Society . This society had commercial and technical problems promoting industrial development in Leipzig.
• Stöhrer became well known through his numerous publications . This also includes his articles in the “Polytechnisches Zentralblatt” and in the “Annalen der Physik und Chemie”.
• In 1860 he was awarded an honorary doctorate (honoris causa) from the University of Jena for his groundbreaking achievements .
• Stöhrer also became an honorary citizen of Leipzig.

literature

• Lothar Hirsemann: The development of electrical engineering in Leipzig up to the subject at the municipal trade school. Scientific reports of the Technical University, Volume 3, Leipzig 1988, ISSN  0138-3809 .
• Helmut Gast: On the history of the technical educational institutions in Leipzig. Colloquium "On the historical development of technical sciences and technical education in Leipzig" on October 27, 1988. Scientific reports of the Technical University, No. 12, Leipzig 1989.
• Author collective of the THL, management and overall editing Norbert Kammler, Helmut Gast: Technical education in Leipzig - from the beginnings to the present. Fachbuchverlag, Leipzig 1989.
• Lothar Hiersemann: The development of automation technology from ancient Greece to the invention of the hand wheel clock in the 10th century. Contributions to the history of technology and technical education, volume 2. Technische Hochschule, Leipzig 1991.
• Alfred Löhr: Electrical communications engineering. In: Jörn Christiansen (Ed.): Bremen is getting bright, 100 years of living and working with electricity. Hauschild: Bremen 1993, pp. 301–310, here p. 317 (note 29), fig. 12.
• Werner Kriesel , Hans Rohr, Andreas Koch: History and future of measurement and automation technology. VDI-Verlag, Düsseldorf 1995, ISBN 3-18-150047-X .
• Lothar Hiersemann: Emil Stöhrer - inventor of electromagnetic machines. In: University of Technology, Economics and Culture Leipzig. The rector Hubertus Milke (ed.): Leipziger technician portraits. Printing and binding Gebr. Klingenberg Buchkunst Leipzig 2007.
• Robert Knott: Article Stöhrer, Emil. In: Allgemeine Deutsche Biographie , published by the Historical Commission at the Bavarian Academy of Sciences, Volume 36 (1893), pp. 322–323. Digital full-text edition in Wikisource, URL: https://de.wikisource.org/w/index.php?title=ADB:St%C3%B6hrer,_Emil&oldid=2493946 (Version from February 1, 2016, 1:35 p.m. UTC)

Web links

• Homepage of the HTWK Leipzig