Tube power plants 1 and 2 of the German city of Duisburg, is visible from far away, it is one of the local attractions.
Power plants built in 1967 and still supply the city with energy and heat from coal.
Total pipe plants, located at the loading platforms, consists of three closely standing tubes, which discharge the flue gas. In the center is the tower, which is located inside the elevator, lifting people to a height of 180 m at a speed of more than 3 m / s. From a platform for visitors to the steep spiral staircase leads to the engine room, resembling a giant mushroom growing among the chimneys.
On the site can only be reached by elevator. For safety, a second elevator — evacuation, it can be used to free people from the cabin lift and bring down to earth. Because it takes a lot of time, it is especially important to work the lift was reliable. For this reason, in the past year it has been modernized elevator.
The old elevator control system is installed in the 80s of the last century, because to find the spare parts was not easy. Printed circuit board recovered by hand, and is also affected the decision of staff power, in charge of the lift and replace the control system. However, an old elevator and set it in motion DC motor power employees want, if possible, leave. This is not unusual. However, although the machine room is located above the area for visitors, a control system located in the basement of the power plant, at the bottom of the elevator shaft.
When the elevator design, this separation was justified: it is possible to immediately detect the fault, it is convenient to maintain and repair, especially taking into account the lack of stairs to the top of the tower. Located at the height of the engine room has been exposed to wind and weather conditions, which created a system for electronics adverse conditions. The tiny machine room too crowded to accommodate additional cabinet to the control system.
It took a very long cables. The engine was located at a distance of 220 m from the control system. This also influenced the decision to keep the DC motor. Management has made an order power company Otis, which then instructed the Emotron companies to design and put into operation a control system for an existing elevator.
Position sensor on the motor DC Otis’ in the elevator, moving at a speed of 3 m / s.
The main difficulty was to lossless forward signals from the position sensor. Required position sensor, which would be responsible for the accurate determination of the velocity of the elevator car in the shaft. To this end, the company chose a sinusoidal position sensor companies Wachendorf Automation GmbH & Co. KG, has conducted extensive testing of such devices and successfully use the standard version of the device with a cable length up to 150 m. The company then Wachendorf has worked closely with the company to organize a reliable signal transmission over a distance of 220 m, in spite of the significant interference.
— We have modified our position sensor in accordance with the terms of Duisburg — said a consulting engineer for Applied Systems Company Wachendorf Automation Kai Nagel.
Goetz Benchek the company Emotron elaborates:
-In this case, the position sensor operates on 15 V, instead of the usual 5 V, and its terminals are special resistors.