The Ottenbach Small Hydro is a 1920 electrified small hydroelectric power station of the former Silk Weaving Mill A. F. Haas & Co. in the Swiss village of
Ottenbach
Ottenbach is a municipality in the district of Affoltern in the canton of Zürich in Switzerland.
History
Ottenbach is first mentioned in 831 as ''in loco vocato marcha Hotumbacharia''. In 1169 it was mentioned as ''Arnoldus de Ottonbac''.
...
. It is preserved in its original condition of 1920, still able to operate, aimed to be an historical witness of the industrial archaeology. The ensemble of factory, power plant and hydraulic structures is a cultural asset under preservation order.
History
From 1645 onwards, the millers of Ottenbach and Rickenbach used in addition to the ditches in the village the water of the
river Reuss to grind the grain, because those did not supply enough water during the summer months. In 1833, the
Canton of Zürich
The canton of Zürich (german: Kanton Zürich ; rm, Chantun Turitg; french: Canton de Zurich; it, Canton Zurigo) is a Swiss canton in the northeastern part of the country. With a population of (as of ), it is the most populous canton in the ...
granted the license to use the water to operate a grain mill. In 1836 the miller Jakob Beerli built a canal with a dam in order to bring the water of the Reuss to the millwheel in a more regulated manner.
In 1869, the Zurich Mechanical Silk Weaving Mill (owned by Bodmer & Hürlimann) bought the former mill from Heinrich Schmid, who had bought it from his cousin Jakob Beerli and converted it into a textile factory. On November 9, 1871, Bodmer & Hürlimann received the water rights concession No. 19 from the Canton of Zurich, signed by the Town Clerk and Swiss poet
Gottfried Keller
Gottfried Keller (19 July 1819 – 15 July 1890) was a Swiss poet and writer of German literature. Best known for his novel '' Green Henry'' (German: ''Der grüne Heinrich'') and his cycle of novellas called ''The People from Seldwyla'' (''Die Leu ...
. It was based on the old water rights concession of 1833 with minor modifications, and water power was used as a direct mechanical drive of the looms via the still existing bevel shaft and the transmission system. The mill wheel was replaced by a
Jonval turbine
The Jonval turbine is a water turbine design invented in France in 1837 and introduced to the United States around 1850 and were widely used. The Jonval turbine is a "mixed-flow" turbine design. Mixed-flow designs were well suited for the low-head ...
(Bell Maschinenfabrik) in 1881. In 1909, the old turbine house was replaced by a new building according to the plans of the Hickel Engineering Office in Lucerne, and the bottom of the discharge channel was lowered so that a new
Francis turbine
The Francis turbine is a type of water turbine. It is an inward-flow reaction turbine that combines radial and axial flow concepts. Francis turbines are the most common water turbine in use today, and can achieve over 95% efficiency.
The proces ...
(Uzwil Machine Factory) could be inserted into the former idling channel. At low water-levels in winter, a coal-fired locomotive was coupled to the transmissions instead of the turbine system. Two horse-drawn carts had to travel back and forth between Ottenbach and
Affoltern am Albis railway station
Affoltern am Albis is a railway station in the Swiss canton of Zürich, situated in the municipality of Affoltern am Albis. The station is located on the Zürich to Zug via Affoltern am Albis railway line. Affoltern am Albis station is less than ...
to bring the required amount of coal.
In 1920, today's plant components were built in and the looms were electrically powered by a new, more powerful Francis turbine and a generator. During the global economic crisis, the company was overtaken by the Silk and Decorative Fabric Weaving mill A.F. Haas & Co., which produced until 1970 and since then has been running a textile trading business, today named Haas Shopping.
In 1977, the canton of Zurich purchased the adjacent nature reserve of Bibelaas, including the small power station, canal and dam, as a measure to protect the banks of the Reuss. In 2011/12, the headrace canal and the dam had to be repaired due to the damage caused by the floods of 2005 and 2007.
Turbine house
The machines and drives in the turbine house date back to 1920, when the looms were converted to electric operation. In the basement there is the turbine, guide vanes and water chamber. In the engine room, the large bevel gear wheel, which sits on the turbine axis and is equipped with original wooden teeth from 1920, is set in motion by the rotational force of the turbine. With the small bevel gear wheel and the transmissions, the rotational force is transmitted to the bevel shaft, which drives the generator at 1000 revolutions per minute. The regulator measures the speed and then regulates the flow of water to the turbine in order to adapt the output to the water supply. In island operation mode it maintains the main frequency of 50 Hz.
The water supply can be regulated by means of the guide vane, which is arranged around the turbine and consists of adjustable vanes. The water flows through the guide vanes onto the blades of the approx. 62 kW (84 hp) Francis turbine built by the Maschinenfabrik Bell and sets them in rotation.
From 1920 onwards electrification was installed. The looms were no longer driven mechanically via the bevel, but electrically with the electricity produced by the generator. Excess electricity was fed into the public grid from 1939 onwards, with the generator frequency being determined by the grid. The complex transmission system with large wheels and leather belts reminds us of the time before 1920 and, conversely, electricity could be drawn from the grid when the turbine was at a standstill.
Built in 1920 by
Brown, Boveri & Cie
Brown, Boveri & Cie. (Brown, Boveri & Company; BBC) was a Swiss group of electrical engineering companies.
It was founded in Zürich, in 1891 by Charles Eugene Lancelot Brown and Walter Boveri who worked at the Maschinenfabrik Oerlikon. In 1 ...
, the three-phase synchronous generator with attached exciter machine has an output of 62 kW. At a frequency of 50 Hz it has a speed of 1000 revolutions per minute.
In the engine room, the underground guide vanes are controlled by the regulator built by Bell Maschinenfabrik, to which they are connected by a linkage. Once the turbine has been started up with the handwheel, the oil pressure with the centrifugal governor ensures that the desired number of revolutions is constantly maintained.
The
Art Deco
Art Deco, short for the French ''Arts Décoratifs'', and sometimes just called Deco, is a style of visual arts, architecture, and product design, that first appeared in France in the 1910s (just before World War I), and flourished in the Unite ...
-style switching wall with electromechanical measuring devices from Trüb, Fierz & Co. was used to control the lighting in the rooms hosting the looms. The direct current required for this was generated with a dynamo that is no longer available today and stored in an accumulator battery consisting of 150 glasses each filled with 100 litres of sulphuric acid.
Factory canal and side weir
![HKO Schwemmfalle](https://upload.wikimedia.org/wikipedia/commons/6/6f/HKO_Schwemmfalle.JPG)
By the 200-metre-long dam - the longest of its kind in the Canton of Zurich - the Reuss water is directed through four gates to the headrace channel. With the gates, the amount of water flowing into the headrace channel can be regulated. The gravel water trap is used to flush away gravel and sand from the canal. For this purpose, it is opened once a year for a few days.
The small power station is a run-of-river power station in which the water level of the headrace and tailrace canals is the same and the water can only be stored for a short time by closing the overflow or idle gate. When the gate is closed, the water is backed up until it flows over the gates out of wooden panel.
In operating mode, the idle channel is closed and the turbine inlet channel is opened. By lifting the turbine inlet gate, the water from the headrace channel can flow through the flotsam screen into the turbine inlet. A worm gear is used to move a rack attached to the latch in order to lift or lower the wooden panels of the gate, consisting of several boards in their lateral guide rails. Since 1900, the canal, dam, alluvial traps have remained practically unchanged. The water out of the turbine flows back into the Reuss via an tailrace canal.
Association Historical Ottenbach Small Hydro (VHKO)
Founded in 2013, the association is responsible for regular operation, ongoing maintenance work and flood protection on behalf of the Canton of Zurich's preservation of historical monuments. It carries out inspections and demonstrations (operation of the plant) for the public and researches and documents the technical and economic-social history of the small power plant.
Group tours are available on request, open days are published on the website. The original equipment of 1920 is running for guided visits.
See also
*
List of power stations in Switzerland
The following page lists power stations in Switzerland. For traction current see List of installations for 15 kV AC railway electrification in Germany, Austria and Switzerland.
Hydroelectric
There are 556 hydroelectric power plants in Switzerla ...
References
External links
{{Commonscat, Kleinkraftwerk Ottenbach, Ottenbach Small Hydro
Website Ottenbach Small Hydro
Energy infrastructure completed in 1920
Dams in Switzerland
Hydroelectric power stations in Switzerland