Timestamps:
0:00 intro
0:25 normal ride
2:57 motor room
7:18 car top / lift shaft
This video presents a group of two lift that are among the rarest to still be found. They were constructed in 1975 by Schlieren and are still in almost fully original condition, the only things replaced being the door drives.
These lifts run on Aconic controllers. The Aconic was invented by Schlieren in 1959 and first ever installed in 1961. It was a revolutionary concept, being a controller not operating on relays, but on transistors. The Aconic controller is fully silent, and has no moving parts. It was Schlieren's flagship, mostly installed in high-demanding applications such as high-rise buildings and groups of multiple lifts. Aconic made it possible to use algorithms to serve calls that are more adcanced than what would be possible with relay controllers.
The Aconic controller consists of resistor frames (blue) with transistor blocks (yellow) plugged into them. The transistor blocks can easily be replaced. The resistors in the resistor frame are used to connect the transistors so that they make connections. With this concept, any circuit needed could be built. Aconic uses a set of predefined circuits that are combined so that they fulfil the functionality required. All signals within the controller are digital, they can only either be on or off.
The Aconic also uses some PCBs. These carry out basic functionalities that cannot be achieved within the resistor frames. This includes an oscillator, input debouncing, reed relays for lanterns, transistors for switching contactors and more.
The floor selector system of Aconic is fully contactless through inductive switches on the car top and vanes in the shaft. The floor position is stored digitally within the controller itself, there is no mechanical device needed.
The second interesting system installed in these lifts is the Monotron drive system. It was originally invented in the 1950s by Schlieren and has then gone through several iterations. This install here uses the Monotron III system, which already uses PCBs.
Monotron works as follows:
The motor has two windings and an eddy current brake. The windings have 4 and 6 pairs of poles. Any trip begins with the slower winding being energised. On a single floor trip, the motor will not go faster than this. On a multi floor trip, the Monotron drive will know through the tacho generator when the motor is spinning fast enough to switch to the second speed. On revision, the additional contactor SRE will switch both windings in series, resulting in a slower speed.
The levelling of Monotron always happens directly, there is never a creep distance. This was the great selling point of Monotron: Offering speeds of up to 1.75m/s, which is faster than what can be achieved with a pole-changer, without needing a Ward-Leonhard group (DC generator).
The levelling is done by switching off motor power at the break engage point. Now the transistors on the RED print will supply the eddy current brake (rear part of the monoblock motor) with a DC voltage. The tacho generator produces a voltage proportional to the speed of rotation. Integrated over time, this will reconstruct travel distance. The braking distance is set to a fixed value which the system tries to match exactly. During the braking sequence the Monotron system continuously compares the setpoint of the speed with the actual speed and will therefore either increase or decrease the voltage on the brake to adjust the braking force. This system enables perfect levelling independent of car load and direction of travel.
The Aconic mostly being used in high-rise applications means that by today almost none of these controllers remain, as high-rise lifts are very unlikely to outlast 40 or more years without any modernisation. Since Schindler bought Schlieren in 1960, Schindler as well installed this system in their high-rise lifts. But even the number of remaining Aconic controllers installed by both companies combined is very low.
There were other drive systems available for the Aconic, depending on the use case. High-Rise lifts could make use of the Transitronic system, which is an electronically controlled Ward-Leonhard drive (DC gearless) that also featured levelling with no creep distance.
Manufacturer: Schlieren, 1975
Capacity: 16 persons / 1200 kg
Type: Traction, 1:1 roping
Floors: 10: E, 1-9
Fixtures: Schlieren Drulux
Speed: 1.75 m/s
Travel height: 25.2m
Logic: Aconic
Drive: Monotron III
Motor: KDL, 22 kW
Gearbox: Schlieren S14, ratio 2/70
WARNING/DISCLAIMER: DO NOT attempt to copy anything shown in the video without having the proper knowledge of how to do so! LIFT SHAFTS and MACHINE ROOMS are very DANGEROUS places and are NOT MEANT to be accessed by inexperienced or untrained personnel!
Dangers in these environments include but are not limited to crushing, electrocution, falling and burns.
29 июн 2024
