Today the industrial evolutions and developments have created an accelerating growth in the production cycle and manufacturing technologies so that using of techniques, tools and machinery and also using of transportation and transition equipment, labor productivity and more efficient using of time have resulted in the production process. Among these tools are conveyer machinery and lifts. These equipment do a high volume of handling raw materials, goods, equipment, spare parts, scraps and wastes and so on in the current industry that it has been very effective to reduce the production costs. On the other hand, the increasing trend of constructing the residential, commercial and industrial units and the country population’s need to housing and related services has led that the service and welfare productions associated with building industry have a more active presence in the economy in recent years.
The elevator and lifts industry has become one of the popular industries due to the society need, government policies in mass housing and also increasing the services level in various residential and commercial applications and a significant growth has been established in the field of manufacturing types of elevators and lifts and also transferring of technology and these industries dynamics in the country in recent years.
Ascenseur is a French word and is s electromechanical device that most of elevators’ parts and supplies was mechanical and electrical at the beginning of elevator invention but this device also evolved along with sciences advancement in the field of electronics and semiconductors and artificial intelligence field entering to the industry and it was situated as a fully functional device with the domain of quite widespread access level among urban communities. In reviewing of the buildings architecture in the past, it is received that there has been ability to construct tall buildings but perhaps the reason for why this work has not spread, has been many steps of the buildings. This problem continued until a man named Elisha Otis, an American mechanic, unveiled it at an exhibition in New York in 1854 by inventing a latched wheel on lifting and by using it, and this invention was a beginning of an evolution for wide using in order to exploit in the construction of high-rise buildings. If the rope breaks, it will stop the lift shortly after falling.
It is said that Naser al-Din Shah Qajar says about definition of elevator in his travelogue to Europe: we went to St. Thomas hospital …. Of underthings orders and they were laying an ill person on the bed and they were dragging from the downward room to the top level, it was very spectacular that the ill did not move.
Types of elevators:
All elevators are similar to each other in having features such as having a cabin, vertical movement and stopping at different levels. But they are different in terms of how to apply the driving force behind the cabins and they divided to four groups as follows.
- Traction elevators: the work basis of these elevators is based on friction force between wire ropes and sheave. There are some weights as cabin weight plus half of cabin capacity in the weight frame. For example if the cabin capacity is 900 kg (i.e. a 12 persons passenger elevator because the average weight is 75 kg per person) there are some weights as 450 kg plus the cabin weight in the weight cadre. The required tension force to move the cabin is reduced by this weight because if you consider the cabin capacity, the weight difference between weight cadre and cabin will not exceed of half of cabin capacity (450 kg in the previous example) under any circumstances and the elevator traction system will consume the power extremely to handle a mass as half of the cabin capacity in moving up or down.
Hydraulic elevators: these elevators must move all cabins and passengers and because of absence of weight cadre and hydraulic jack system in hydraulic elevators, it needs for more powerful engines. In these elevators, a three-phase immersed in oil motor as well as a special electric valve that is so called as power unit has the task of providing the oil pressure for the hydraulic jack. The hydraulic system uses a significant power only in half of its moving distance (upward only) and it uses of gravity force in the other half (downward only) and this matter eliminates its higher power consumption than the two-speed elevators.
Vinci elevators: is a types of elevators that is suspended by chain or steel rope and the propulsion is come into it in a way other than friction. There is not weight frame in this types of elevators.
Magnetic elevators: in these elevators, the rails and connected equipment on the wall of elevator shaft with a permanent magnet play role of motor stator and the elevator cabin plays role of rotor. The magnetic field is made and is induced to the rotor by connecting electricity to the stator. The made magnetic field is cut-off in some points and the mounted windings become charged on the rotor by inducing electricity by stator windings and so the cabin is driven.
Workshop elevators: the workshop elevators are supplement and accelerator of tower construction and high-rise structures. These elevators are able to be assembled from the beginning by themselves and be high risen by the building’s structure. These elevators have capability to work a height of 500 meters and more than it and they are manufactured in 1, 1.5 and 2 tons capacities.
Propulsion: the elevators propulsion was previously of direct current motors and was by direct current electricity that the various starters such as ward-Leonard drive system are used for this types of motors. By eliminating of direct current motors (DC) and introducing of three-phase induction motors, for years that is used of electric three-phase induction motors or asynchronous and recently is used of permanent magnet motors (PM) or synchronous. The brake lining mechanism is used in these motors that prevents motor’s unwanted movement in the stopping status by using of friction force.
Elevator control board: the elevators were commanded by commandership Relay board in not far past. The control was reaching from these boards to so-called two-speed motors. These motors were able to move with two fast and slow speeds by their two windings. The elevator was moving with fast speed and in order to stop in the floors and decreasing the stop time shake was changing to slow speed and it was stopping with this speed over a short path.
Elevator drive control board: using of elevator control boards has become common by industrial electronic development and inverters more cheapening and they gradually replace of contactor systems. Reduction of shakes when changing speed and increasing the power factor due to connecting to mediator through inverter capacitor bank is among advantages of inverter control boards that are known as drive boards.