【 Weak current College 】 elevator should be noted that several technical issues

As a building with lift is increasing, more and more investors and design units encounter such a problem — how to choose for your project? this article in conjunction with the elevator lift some technical problems on some selection configuration should be taken note.
1. determine the main parameters of the transmission capacity — lift the quantity, the load capacity and rated speed
The elevator should have adequate transmission capacity. Conveying capacity can meet 5 minutes peak demand by ladder, you can view elevator choice is reasonable.
Elevator arrival hall interval should not be too long. General requirements should not exceed 2-3 minutes. Simple estimation methods: elevator from the bottom to the top level should not exceed 45 ~ 60s.
Waiting time and staircase time should be as short as possible. This is to meet the requirements of passengers. More acceptable limit is: Hou staircase no more than 30 s, staircase time does not exceed the 90s.
At present it is worth noting that the blind pursuit of lift speed. High-speed elevators would not necessarily reduce the staircase time, improving transportation efficiency. In fact also consider building height, number of stops and dispatch station, not too high, and stop a few more buildings, high-speed elevator only in General, low-speed operation, and high-speed elevator and escalator stop layer of medium-speed switch time and passengers are time little difference. In order to improve efficiency, reduce the elevator passengers staircase time, in recent years there has been direct dock, open the door, the door in advance and other new technology quickly. Direct dock is running curve off slow leveling period, elevator from the rated speed is reduced by a reduction in speed to zero velocity, this is just flat floor location. If there is a slight deviation, available "relevelling" technology be adjusted; advance door refers cabin had not yet reached zero velocity is not completely flat layer ofa safe distance from the start actions within open machine, pending the car entirely accurate when leveling the door was open; fast door basically refers to meet maximum blocking the door and the door maximum kinetic energy limitations increase closed average speed, thus shortening the closing time. These measures in each stop of leveling and switch saves time in the process appears to be no more, but many tier points accumulated its effect than simply improve elevator speed is much better.
2. the need to focus on the consideration of technology performance — reliability, advanced quality and comfort
The so-called reliability refers to the elevator system within the prescribed time, the ability to maintain the required functionality is built in a large number of statistical data based on the concept of probability. Our reliability requirements for elevators refers to failure at run time to as little as possible, and in the event of a failure to be able to easily excluded. While the impact on the safety aspects such as safety clamp, speed limiter, safety edge, grating door area protection system to absolutely cannot fail.
Elevator's advancement at present mainly in drag and control technology, power electronics and computer technology has fundamental progress, vector control FM surge control technology (VVVF) makes the induction motor speed performance achieved the level of DC motor using the computer logic control system are replacing relay and elevator control, network control and application of fuzzy control theory and elevator dispatching control intelligent direction.
Comfort mainly refers to the elevator of acceleration, vibration, noise, decoration, lighting, and other indicators, which aims to provide a full and comfortable environment by ladder. Early comfort requirements mainly overweight and weightlessness, annoying noise and anxiety, and other control in the passengers endure scope; modern comfort the pursuit of the passengers is not only physically but also psychologically to ride the elevator to go up and down when the "enjoyment".
In the elevator when obviously reliability is the most important indicators. GB GB10058 provides: elevator operation breakdown of less than 6 million times 5 times as qualified product, less than 2 times as first-class materials, less than 1 time for excellence in goods, and in Appendix b defines the fault. Now you should be aware of the reliability of ignoring trends, there is a noteworthy trend is excessive pursuit of comfort. Some projects in the elevator when the elevator deliberately observe slight vibration, noise and the decoration of the "beauty effect", not on other technical issues, eventually causing the selection slip, this case can be said that nothing new.
3. drag the control – AC two-speed, voltage converter and FM speed
Elevator stop layer ladder without zero. Normal run-time to the rated speed for uniform linear motion. At zero speed and rated speed for acceleration or deceleration transition, this time motor speed control called speed.
In the cabin for acceleration or deceleration movement, passengers will be overweight and weightlessness. Ordinary people on overweight and weightlessness of carrying capacity is very limited, the Chinese GB GB10058 provides a value cannot be greater than 1.5m/s2. In addition, if the acceleration is always tired, passengers will have the feeling of being even vertigo. This requires the acceleration rate as small as possible. DC motor with good speed performance, but DC motor with a power ring, a large maintenance workload. AC induction motor with simple structure, reliable performance, along with the computer and the development of power electronics technology, with different timing modes to meet the different needs of lift. Low-speed elevator often adopts AC two-speed (AC-2) programme, fewer failure points low probability. The main drawback is leveling accuracy and riding comfort a trade-off. Medium-speed elevator use of adjusting speed (ACVV) technology. This method is used to change the speed of change of motor torque, the motor torque and load torque adjustment, the difference between the positive and negative control motor angular acceleration, and full closed loop control of the elevator in controlled velocity and Acceleration, has become the dominant products made in the elevator.
In the last decade has FM surge speed (VVVF) new technology. This conversion technology is developing rapidly, its speed performance has fully comparable with the DC motor. In addition to the excellent comfort, leveling accuracy has also greatly improved, but also provides significant energy saving effects.
4. signal control – relays, PC and PC
Passenger lift, first in the floor to lift a call signal and entered the elevator car and want to register his going to the floor. These numbers will be randomly, the elevator is going to keep the signal controller records and make arrangements for the implementation of the order, this is the elevator of signal control or logic control technology. Generally, early elevator and drivers to handle signals and issued a directive that this control is called the signal control. Then use logical line according to the rules of procedure for answering and execution, Elevator can have drivers or no drivers, this control is called the set control. When the elevator Hall is equipped with 2-3 elevators, accessible by common call button enables the elevator complying with the provisions of the order automatically scheduling, this control is called parallel control. When there are multiple elevators installed, increasing the number of signals, the controller according to the operation of any lift quickly and in accordance with established scheduling technology to automatically dispatch called elevators were to answer the call of the stations, this control is called a group control.
Signal control and relatively simple set of control over an extended period of time is achieved by a relay. Later, with the development of computer technology, industrial common PLC-PC. In the number of stations and features require more cases, many elevator companies use 8-bit, 16-bit or 32-bit MCU developed dedicated microcomputer control system, also uses serial communications, microcomputer network control and other new technologies, in the scheduling system design and introduction of fuzzy control theory, the elevator in addition to many new functional reliability and scheduling efficiency has improved significantly.
5. should pay attention to one model-hydraulic elevator
Hydraulic elevator rise of uniform linear motion through the pump to certain flow to the oil cylinder injection plunger oil to rise, decline of uniform linear motion through the fuel tank of oil to certain flow into the tank, the cabin weight plunger down, there is a timing problem. In the cabin rises in general there are two ways, one is the volume control, or is called pump control cylinder speed control, throttle control, or is called valve cylinder control speed. In the car down general use throttle control.
Advantages of hydraulic elevator is low on the engine room, with a larger carrying capacity, safety issues are also relatively small. The disadvantage is that the limited lifting height, generally not more than 6-storey building; elevator speed nor very quickly, generally not more than 1m/s.
Freight elevator, especially large-tonnage (2t) freight elevator, priority should be given to the selection of hydraulic elevator. Old building additional lift is hard to find a suitable room and well road, hydraulic elevator showed obvious advantages. In addition, villa-style 2-3-storey residential elevator for settings, hydraulic elevator is undoubtedly the most desirable models.