International Electrotechnical Exhibition

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Contemporary image showing the entrance to the exhibition site with arches and electrically powered waterfall
International Electrotechnical Exhibition of 1891 on the site of the former Western Railway Stations at Frankfurt am Main
The transmission route

The 1891 International Electrotechnical Exhibition was held between 16 May and 19 October on the disused site of the three former Westbahnhöfe (

Frankfurt am Main, Germany. The exhibition featured the first long-distance transmission of high-power, three-phase electric current, which was generated 175 km away at Lauffen am Neckar.[1]
As a result of this successful field trial, three-phase current became established for electrical transmission networks throughout the world.

History

The "Elektrotechnische Gesellschaft" (Electrotechnical Society) was founded in Frankfurt in 1881 with the aim of promoting electricity and, in particular, furthering research into its application for industry and technology. Three years later, some ten manufacturers of electrical equipment had set themselves up in the city. In around 1890, some of the enterprises were established which would later become major firms in Frankfurt: Hartmann & Braun, Staudt & Voigt (from 1891 Voigt & Haefner) and W Lahmeyer & Co (from 1893 Elektrizitäts-AG, previously W Lahmeyer & Co). And it was in Frankfurt that the "second

industrial revolution" began to emerge – a revolution that would bring about fundamental changes similar to those created 100 years previously by the introduction of the steam engine to the world of work. In 1891, the German electrical industry was ready to demonstrate its capabilities to the world at the International Electrotechnical Exhibition. A site was chosen – that of the former western stations between the city and the new main station
, which had been completed in 1888.

Prompted by the Paris "

marks
.

As far as Germany was concerned, the International Electrotechnical Exhibition settled once and for all the question of the most economical means of transmitting electrical energy. When the exhibition closed, the power station at Lauffen continued in operation – providing electricity for the administrative capital, Heilbronn, thus making it the first place to be equipped with a power supply using three-phase AC. The name of the local power company (ZEAG) bears testimony to this event. The Frankfurt city council constructed its own power station near the harbour; yet another was built by a private company in the suburb of Bockenheim.

Equipment

A hydraulic turbine at Lauffen powered a three-phase alternator with a revolving field. The alternator revolved at 150 revolutions per minute, and had a rotating field magnet with 32 poles. It was rated at 300 hp and had a terminal voltage of 55 volts. The frequency of the current was 40 Hz. Power from the alternator was stepped up to 8000 volts for transmission by oil-insulated transformers. Later tests were carried out with transmission voltage up to 25,000 volts (between phases).

The

transmission line was erected with the assistance of the German Post Office and used about 60 tonnes of copper wire, 4 mm
in diameter. At the exhibition, the voltage was stepped down by further oil-filled transformers and connected to motors and a motor-generator system for lamps.

Overall efficiency from turbine to load was an average of 75%, which resolved many doubts of the practicality of long-distance electric power transmission.[2]

Gallery

  • Entrance to the exhibition
    Entrance to the exhibition
  • Distinguished visitors at the power station: photograph by Oskar von Miller. Among others: Karl von Leibbrand, Emil Rathenau, Marcel Deprez, Gisbert Kapp, Dr. John Hopkinson, Charles Brown, Emil Huber, and the telecommunications pioneer William Henry Preece, who would later be knighted.
    Distinguished visitors at the power station: photograph by Oskar von Miller. Among others: Karl von Leibbrand, Emil Rathenau, Marcel Deprez, Gisbert Kapp, Dr. John Hopkinson, Charles Brown, Emil Huber, and the telecommunications pioneer William Henry Preece, who would later be knighted.
  • Waterfall powered by a 100 HP Pump
    Waterfall powered by a 100 HP Pump
  • Three-phase motor with associated pump behind the artificial waterfall. The map shows the route of the overhead cable, which followed approximately that of a railway line. There were some 3,000 masts, 9,000 oil insulators and 60 tonnes of (4 mm)-diameter copper wire.
    Three-phase motor with associated pump behind the artificial waterfall. The map shows the route of the overhead cable, which followed approximately that of a railway line. There were some 3,000 masts, 9,000 oil insulators and 60 tonnes of (4 mm)-diameter copper wire.
  • Lithograph showing the pump and transformer house behind the waterfall
    Lithograph showing the pump and transformer house behind the waterfall
  • Power station at Lauffen where current was generated
    Power station at Lauffen where current was generated
  • Three-phase generator at the Lauffen power station
    Three-phase generator at the Lauffen power station
  • The exhibition featured the first ascents for passengers in a tethered balloon
    The exhibition featured the first ascents for passengers in a tethered balloon
  • Official poster
    Official poster
  • Exhibition site
    Exhibition site
  • Stand of Siemens & Halske
    Stand of
    Siemens & Halske
  • Stand of Helios AG
    Stand of Helios AG
  • Postcard on sale for the (then) princely sum of 5 pfennigs
    Postcard on sale for the (then) princely sum of 5 pfennigs
  • Postage stamp marking the 100th anniversary of the transmission of electricity
    Postage stamp marking the 100th anniversary of the transmission of electricity

See also

References

  1. ISSN 2080-8593
    .
  2. ^ * Silvanus P. Thompson, Polyphase Electric Currents and Alternate-Current Motors, E. & F. N. Spon, London 1895. Thompson gives a detailed description of the Lauffen and Frankfurt machines on pages 27–33, with illustrations. The transmission system is described on pages 106–110

Bibliography

External links
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