The difference between traction and hydraulic elevators

The most famous type of elevator used in buildings is usually the traction type. In fact, in general, it can be stated that the driving force in this type of elevators is provided by an electric motor that is usually installed on the top of the elevator shaft in a place called the engine room. On the top of this engine, there are some steel cables or towing wires that are connected to the elevator cabin on one side and to the elevator weights on the other side, which are located in a metal frame called the weight frame. It is interesting to know that the material These weights are usually made of cast iron or concrete and the weight of these weights is equal to the weight of the cabin plus half the capacity of the cabin. In fact, the weight of each person in elevator calculations is usually 75 kg; Therefore, the reason for putting weights in the elevator system is to help lift the elevator, otherwise, very powerful motors with high kilowatts should be used for this. It should be noted that the basis of the operation of these types of elevators is based on the force of friction between the towing wires and the motor shaft.

It is interesting to know that recently hydraulic elevators have become very popular and have opened their place among home users. In fact, in Europe, more than 70% of hydraulic elevators below 5 floors are used, and the advantages of this type of elevators include smooth movement at the initial start; very low breakdown and depreciation; Ease of troubleshooting and repair; Creating beautiful and glass elevators due to the removal of the weight frame and tow wire; the need for a light structure; No need for an engine room on the roof; He pointed out the creation of high tonnage and heavy duty elevators and the beauty of the roof of the house as well as its precise alignment on the floors.

Generally, hydraulic elevators work with electric motor, oil pressure pump and hydraulic jack. In fact, in hydraulic elevators, because there is no weight frame and the hydraulic jack system must move all the cabins and passengers; Therefore, there is a need for stronger engines in the formation of their system. It is interesting to know that in these elevators, a three-phase motor immersed in oil along with a special electric valve, which is called a power unit, has the task of providing oil pressure for the hydraulic jack. To start the engine, due to the presence of stronger engines, if using a drive or soft starter, a much higher cost is needed, so usually the common star-delta system is used to start the hydraulic motor pump; But this engine and pressure are only needed for upward movement and there is no need to turn on the engine and use power to move the cabin downwards, and just by opening a valve and emptying the oil, the cabin jack slowly moves downwards; In other words, a hydraulic system consumes considerable power only in half of its movement distance (only upwards) and uses gravity in the other half (only downwards).