The 1891 International Electrotechnical Exhibition was held between 16 May and 19 October on the disused site of the three former ( Western Railway Stations) in

Frankfurt am Main Frankfurt am Main () is the most populous city in the States of Germany, German state of Hesse. Its 773,068 inhabitants as of 2022 make it the List of cities in Germany by population, fifth-most populous city in Germany. Located in the forela ...

Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...

. 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. 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 The Second Industrial Revolution, also known as the Technological Revolution, was a phase of rapid Discovery (observation), scientific discovery, standardisation, mass production and industrialisation from the late 19th century into the early ...

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 A steam engine is a heat engine that performs Work (physics), mechanical work using steam as its working fluid. The steam engine uses the force produced by steam pressure to push a piston back and forth inside a Cylinder (locomotive), cyl ...

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 " Exposition Universelle" ( World Fair) of 1889, Leopold Sonnemann, publisher of the '' Frankfurter Zeitung'' newspaper, interested the Electrotechnical Society in the idea of an exhibition. The Society expressed an interest and started preparations in the same year. However, there was another consideration apart from the setting up of an international exhibition – Frankfurt had an urgent problem to solve. The construction of a central

power station A power station, also referred to as a power plant and sometimes generating station or generating plant, is an industrial facility for the electricity generation, generation of electric power. Power stations are generally connected to an electr ...

had been under discussion in the city's political and technical committees since 1886. However, agreement had still to be reached over the type of current, and opinions were divided between

direct current Direct current (DC) is one-directional electric current, flow of electric charge. An electrochemical cell is a prime example of DC power. Direct current may flow through a conductor (material), conductor such as a wire, but can also flow throug ...

alternating current Alternating current (AC) is an electric current that periodically reverses direction and changes its magnitude continuously with time, in contrast to direct current (DC), which flows only in one direction. Alternating current is the form in w ...

and three-phase current. It fell to the exhibition to demonstrate a commercially viable method for the transmission of electricity. Three-phase current with a minimal loss of 25% would be transmitted at high voltage from Lauffen am Neckar to Frankfurt. This took centre stage at the exhibition and was evidenced in the large three-section entrance gate. The central section took the form of an arch bearing the inscription "Power Transmission Lauffen–Frankfurt 175 km." Rectangular panels flanked the arch: the one to the right carrying the name of the " Allgemeine Electricitätsgesellschaft" ("AEG" – General Electricity Company), which had been founded in 1887; the left-hand panel displayed the name of the "

Maschinenfabrik Oerlikon Maschinenfabrik Oerlikon was a Swiss engineering company based in the Zürich district of Oerlikon (Zürich), Oerlikon known for the early development of electric locomotives. It was founded in 1876 as the ''Werkzeug- und Maschinen-Fabrik Oer ...

" (Oerlikon Engineering Works). The entire entrance was illuminated with 1000 light bulbs and an electrically powered waterfall provided a further attraction. With 1,200,000 visitors from all over the world, the exhibition was an out-and-out success. The cost of a one-day entry ticket for an adult amounted to a considerable 15

marks Marks may refer to: Business * Mark's, a Canadian retail chain * Marks & Spencer, a British retail chain * Collective trade marks A collective trademark, collective trade mark, or collective mark is a trademark owned by an organization (such ...

. 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

at Lauffen continued in operation – providing electricity for the administrative capital,

Heilbronn Heilbronn () is a List of cities and towns in Germany, city in northern Baden-Württemberg, Germany, surrounded by Heilbronn (district), Heilbronn District. From the late Middle Ages on, it developed into an important trading centre. At the begi ...

, 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

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 Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min, or r⋅min−1) is a unit of rotational speed (or rotational frequency) for rotating machines. One revolution per minute is equivalent to hertz. Standards ISO 80000-3:2019 de ...

, and had a rotating field magnet with 32 poles. It was rated at 300 hp and had a terminal voltage of 55

volt The volt (symbol: V) is the unit of electric potential, Voltage#Galvani potential vs. electrochemical potential, electric potential difference (voltage), and electromotive force in the International System of Units, International System of Uni ...

s. The

frequency Frequency is the number of occurrences of a repeating event per unit of time. Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio ...

of the current was 40 Hz. Power from the alternator was stepped up to 8000 volts for transmission by oil-insulated

transformer In electrical engineering, a transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple Electrical network, circuits. A varying current in any coil of the transformer produces ...

s. Later tests were carried out with transmission voltage up to 25,000 volts (between phases). The

transmission line In electrical engineering, a transmission line is a specialized cable or other structure designed to conduct electromagnetic waves in a contained manner. The term applies when the conductors are long enough that the wave nature of the transmis ...

was erected with the assistance of the German Post Office and used about 60

tonne The tonne ( or ; symbol: t) is a unit of mass equal to 1,000 kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton in the United States to distinguish it from the non-metric units of the s ...

s 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.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 pp. 27–33, with illustrations. The transmission system is described on pp. 106–110

Gallery

Lauffen-Frankfurt 1891c.jpg, Entrance to the exhibition Lauffen-Frankfurt_1891b.jpg, 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. Lauffen-Frankfurt_1891a.jpg, Waterfall powered by a 100 HP Pump Lauffen-Frankfurt_1891g.jpg, 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. IEAFrankfurt1891h.jpg, Lithograph showing the pump and transformer house behind the waterfall Lauffen-Frankfurt 1891f.jpg, Power station at Lauffen where current was generated Lauffen-Frankfurt 1891e.jpg, Three-phase generator at the Lauffen power station IEAFrankfurt1891b.jpg, The exhibition featured the first ascents for passengers in a tethered balloon IEAFrankfurt1891c.jpg, Official poster IEAFrankfurt1891d.jpg, Exhibition site IEAFrankfurt1891e.jpg, Stand of Siemens & Halske Internationale Elektrotechnische Ausstellung, Frankfurt 1891, Helios.jpg, Stand of Helios AG IEAFrankfurt1891g.jpg, Postcard on sale for the (then) princely sum of 5 pfennigs Lauffen-Frankfurt1891-1991.jpg, Postage stamp marking the 100th anniversary of the transmission of electricity

References

Bibliography

* Jürgen Steen (Hg.): "Eine neue Zeit ..!", Die Internationale Elektrotechnische Ausstellung 1891. Frankfurt am Main 1991 (Ausstellungskatalog Historisches Museum Frankfurt am Main), * Horst A. Wessel (Hg.): Moderne Energie für eine neue Zeit, siebtes VDE-Kolloquium am 3. und 4. September 1991 anlässlich der VDE-Jubiläumsveranstaltung "100 Jahre Drehstrom" in Frankfurt am Main (= Geschichte der Elektrotechnik, Bd.11). Berlin/Offenbach 1991, * Volker Rödel: Fabrikarchitektur in Frankfurt am Main 1774–1924, Frankfurt 1986, S.30f., * Sabine Hock: ''Mehr Licht für Frankfurt'', Oskar von Miller brachte Frankfurt auf den Weg zur Elektrifizierung, ''Wochendienst'' Nr. 16 vom 26.04.2005, hg. v. Presse- und Informationsamt der Stadt Frankfurt am Main

External links