| Abstract: compared with the traditional control mode, the construction elevator with frequency converter control mode can not only avoid the "slip hook" phenomenon caused by insufficient output torque at the moment of starting and stopping, but also greatly reduce the impact between mechanical systems, and improve the stability and work efficiency in the operation process. Taking the building elevator controlled by T600 frequency converter in a company as an example, this paper analyzes the control principle and electrical system of the building elevator in detail. Key words: construction elevator frequency converter impact stability efficiency 1 Introduction With the acceleration of urbanization in China, the construction machinery industry has also ushered in its golden period of development. As an essential mechanical equipment for building construction, the production capacity of building hoist is increasing year by year. The rising, falling and stopping functions of ordinary elevators are realized through contactor relay control, and the speed is not easy to control, the impact of starting and stopping is large, and the mechanical structure and mechanism are seriously damaged; The running speed is not adjustable, which affects the benefit of the construction enterprise, and the parking stability is poor. Using frequency conversion control, it can realize stepless speed regulation in the starting acceleration and deceleration and braking process of the construction elevator, reduce the impact of the motor on the mechanical system during starting and stopping, improve the stability and comfort during the operation of the construction elevator, prolong the service life of the construction elevator, and greatly improve the work efficiency. Taking the building elevator controlled by T600 frequency converter in a company as an example, this paper analyzes the control principle and electrical system of the building elevator in detail. 2 elevator parameters and electrical system The structural diagram of the elevator is shown in Figure 1. The maximum lifting weight is 3.5t, of which the maximum load is 2T, the self weight is 1.5T, the maximum lifting speed is 35m/min, and the maximum acceleration is 0.3g. The elevator electrical system is mainly composed of main circuit and control circuit The electrical transmission part is composed of two asynchronous motors, which are controlled by a t600-4t37g frequency converter. Each motor has a rated power of 11kw, a rated frequency of 50Hz, a rated speed of 1390 r/min, a rated current of 24a, a rated output power of 37KW, a braking resistance of 4 ohms, and a power of 30kW. In order to improve the torque output by the motor during start and stop, the frequency converter adopts open-loop vector control mode, and is equipped with braking unit and braking resistance. The frequency converter adopts terminal control mode, and the input signals of frequency converter rising, stopping and falling are controlled through the handle with rising, stopping and falling functions. The frequency converter has two output relays 1 and 2, of which relay 1 is set as the fault output function and relay 2 is set as the frequency detection function of the frequency converter to control the holding brake contactor of the motor brake. 3 system commissioning After ensuring the correct wiring of the main circuit and control circuit, the system starts power on debugging. According to the experimental rules of the construction hoist industry, the commissioning is divided into several stages: no-load commissioning, 1/2 rated load commissioning, rated load commissioning and 125% rated load commissioning. Considering the low-frequency torque problem, the frequency converter adopts the open-loop vector control mode, so the motor parameters need to be self-learning before commissioning. There are two kinds of parameter self-learning: static and dynamic. When the load and reducer cannot be disengaged, static parameter self-learning is required. In view of the mechanical characteristics of this industry, static parameter self-learning is usually adopted. The nameplate parameters (f1.02-f1.06) of the motor must be correctly input before self-learning. After self-learning, the stator resistance, rotor resistance and leakage inductance of the motor can be detected. The regulation rules of mutual inductance and no-load current of the motor are as follows: Mutual inductance regulation law: when operating at 1/2 of the rated frequency, the output voltage of the frequency converter needs to be about 190V. If it is low, the mutual inductance value should be moderately increased, and vice versa. When the frequency converter operates at the rated frequency, the output voltage of the frequency converter needs to be about 380V. If it is low, the mutual inductance value will be moderately increased, and vice versa. Regulation law of no-load current: the no-load current is generally 1/3 of the rated current of the motor. The proportion of the no-load current of small motors in the rated current will be higher, and some will reach 50% - 60%. The on-site commissioning verifies that during the operation of the elevator, the logic of the motor's release brake is sound, there is no hook sliding phenomenon, and there is no obvious impact when starting and stopping, and the performance fully meets the user's requirements. 4 Conclusion Using T600 frequency converter, not only makes the design of the whole electrical system of the building elevator simple and reliable, and the whole system is always in a safe running state, but also can quickly eliminate system faults through the frequency converter fault inquiry function; In the process of starting and stopping, the impact between mechanical systems can hardly be felt, which greatly improves the stability and comfort of the elevator during operation, and also greatly improves the work efficiency. | |||||||
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