Shanghai Yingge Solan Compressor Co., Ltd. (200051) successfully applied the high-performance solid-state starting of Yao Cheng, and put forward some precautions in the transformation. Machine high-pressure solid-state soft start compressed air as the fourth energy source of the factory, its importance is self-evident. Therefore, the stability of air compressor equipment is also extremely critical and important. For plants with high demand for compressed air flow, centrifugal air compressors driven by high-voltage motors are usually selected. The centrifugal air compressor has the characteristics of large starting current, large load inertia, and obvious current fluctuation during operation. Therefore, the correct selection of the starting mode of the high-voltage motor is directly related to the stability and service life of the centrifugal air compressor. At present, the starting mode of high-voltage large-sized motors is usually: direct start, series electric anti-buck start, liquid soft start, combine start and solid state soft start. Among them, the high-pressure solid-state soft start is one of the starting methods with relatively new technology and relatively good starting effect. The application of high pressure solid state soft start is less than other start-up schemes. As a well-known compressor manufacturer, Ingersoll Rand not only provides users with high-performance air compressors, but also combines the characteristics of air compressor equipment to design and provide optimized large-scale motor starting solutions. The following describes several commonly used high voltage motor starting methods and their characteristics. When starting at full voltage, the starting current will reach 57 times the rated current of the motor. When the capacity of the motor is relatively large, the starting current will cause a sharp drop in the grid voltage, affecting the normal operation of other equipment in the grid, causing an impact on the driving motor, and also impairing the mechanical device. The reactor is a three-phase structure core coil with a large reactance value. When the motor starts, the reactor is connected to the starting circuit. The large reactance value limits the starting current. When the motor speed increases to near the rated speed, the reactor is short-circuited, the reactor exits the starting circuit, and the motor starts full-pressure operation. When the starting is nearly completed, the fixed reactance will affect the speed of the motor. When the speed is close to the rated value, the voltage at both ends of the reactance is large, and when it is shorted, a large secondary inrush current will be generated. A controllable liquid resistance is connected in the stator circuit of the motor. As the motor starts, the distance between the moving and fixed plates of the liquid resistance is automatically changed according to a predetermined setting, the resistance value is steplessly smoothed, and the voltage of the motor terminal is uniformly increased. In order to achieve the purpose of smooth motor soft start. After the start, the liquid resistance is automatically cut off, and the motor is put into operation. The starting process has a soft start characteristic with a small and constant starting current and a gradual increase in the rotational speed. However, because its liquid resistance requires high ambient temperature, large volume, and cannot be started frequently, the adaptability to the motor and the load is not strong, and the protection function requires an additional device. It is composed of a plurality of thyristors connected in series and parallel, which can meet different current GW general mechanical general mechanical manufacturing and voltage requirements, and control the trigger delay angle of the thyristor to control the output voltage. When the motor is started, the terminal voltage of the motor is increased according to a preset starting curve to smoothly accelerate the motor, thereby reducing the electrical and mechanical impact on the power grid, the motor itself, and the connected equipment when the motor is started. When the motor reaches normal speed, the bypass contactor is turned on. The high-voltage solid-state soft start has the characteristics of small starting current and convenient installation, and also provides perfect protection for the motor. In summary, for large-scale high-pressure centrifugal air compressors, it is more feasible to select a high-pressure solid-state soft start as a starting solution. 1) A variety of starting modes are available, including current limiting start, ramp start and ramp current limit start, to meet the needs of the site to the greatest extent. 2) The high-performance microprocessor digitizes the signals in the control system to avoid excessive adjustment of the analog lines in the past, thus achieving excellent accuracy and execution speed. 3) The signals in the control unit are all optically isolated, and different anti-noise levels are set to avoid the malfunction of the soft starter caused by the interference on the main power grid. 4) Provide a variety of motor protection functions for the motor to ensure that the motor and soft starter are not damaged in case of malfunction or malfunction. 5) Various starting methods: current limiting soft start, voltage index curve, voltage linear curve, current exponential curve and current linear curve, and programmable kick start torque and starting current limit can be applied in each mode. According to different loads, the corresponding starting curve can be selected to achieve the best starting effect. 6) All external control signals are optically isolated and have different noise immunity levels for use in special industrial environments. 7) Power frequency adaptation: The power frequency 50/60HZ adaptive function is convenient for users. 8) The whole process detects the current and load parameters, and has computer protection functions such as over current, overload, underload, overheat, phase failure, short circuit, three-phase current imbalance, phase sequence detection and leakage detection. The on-site centrifugal air compressor model is Ingersoll Rand C70037MX3, and the motor parameters are shown in the table below. The unit uses the Ingersoll Rand CMC controller as the unit control system. Therefore, how to make the high-pressure solid-state soft start system and the CMC controller of the centrifugal air compressor work perfectly together becomes the key to this debugging. The following points are required for debugging. Name parameter value Motor type Two-phase asynchronous cage type rated power / kW rated voltage / V rated current / A rated frequency / Hz rated speed / service factor pole number 1. Starting speed of high pressure soft start Setting Matching with Centrifuge Controller Current Detect Protection Carefully study the CMC controller of a centrifugal air compressor and find that the CMC controller has the function of detecting the change of current in the motor starting from 03s. If the current change cannot be detected within 3s, the CMC controller determines that the motor has failed to start, and the centrifugal air compressor immediately alarms "Motor start failure 〃. Therefore, the parameters related to the starting speed in the high-voltage soft start system are to be compared with the CMC controller. The current detection protection functions are matched with each other. The starting delay of the high-voltage soft start system is set to Is, and the acceleration time is appropriately reduced. 2. The setting of the current protection setting value of the upper-level inlet cabinet, the high-voltage soft start system inlet cabinet and the high-voltage soft start system is as shown in the field. As can be seen from the figure, in order to facilitate the maintenance and maintenance of the high-voltage soft start system, a high-voltage switchgear must be installed before it as the inlet cabinet of the high-voltage soft start system. The protection setting values ​​of the high-voltage switch inlet cabinet are as follows. Pressure switch cabinet soft start system general mechanical manufacturing load rated current). /Overpowered. (R is the rated voltage of the system). The quick-break setting time should be set to 0. The over-current setting time is generally set to 0.7s, but it must be one level lower than the time set by the previous level. The setting of the overvoltage time is generally set to Is. The setting of the above setting value should be matched with the starting current and current limiting multiple parameters of the high voltage soft starting system, otherwise the motor will fail to start the alarm. 3. High-voltage soft start system control program step size problem The working principle of the high-voltage soft start system determines that when the motor reaches the normal speed, the high-voltage soft start system will be out of operation and the bypass contactor will be turned on. Since the motor has reached full speed at the moment of switching, the motor current will drop rapidly. If the program adjustment step of the high-voltage soft start system is not fast enough, the system may not be able to keep up with the current drop speed, and the motor will thus generate a large back electromotive force, resulting in an abnormal sound of the motor at the moment of bypass switching. Therefore, the step size adjustment of the control program of the high-voltage soft start should be precise, and the purpose is to reduce the response time of the control system to the current change as much as possible, so that the motor is smoother and smoother at the switching instant. The current curve of the motor during the start-up period and the start-up period is as shown, and it can be seen that the bypass contactor switching process of the field motor is smooth and smooth. (a) Initial period (b) Start-up period m motor current curve The final high-pressure solid-state soft start system is successfully debugged. The starting current of the centrifugal air compressor is well controlled within 118A, less than 3 times the rated current, and the whole process is started for 30s. When the motor is switched by the bypass, there is no obvious abnormal noise, and the switching process is smooth and smooth, and the expected starting effect is fully achieved. Due to the special characteristics of the centrifugal air compressor's own structure, the starting process of the equipment is not only the acceleration process of the motor from zero to full speed, but also the process of the two systems of the high-pressure solid-state soft start system and the centrifugal air compressor. Therefore, it is necessary to thoroughly study the characteristics of the centrifugal air compressor in order to fully exploit the characteristics of the high-pressure solid-state soft start system without affecting the performance of the centrifugal air compressor. With its professional air compressor knowledge and rich transformation experience, Ingersoll Rand has tailored this set of the most suitable high-voltage motor starting solution. As the technology of high-voltage solid-state soft-start systems matures, it will become a perfect replacement for other motor starting methods in the near future. The measured value of the measured value is compared with the calculated value and measured value of the material b as follows: (Fb - / V) / / V = ​​6.8%. That is, the actual flow value of the circulating nitrogen compressor is 6.8% more than the measured value. After the check The flow rate of circulating nitrogen gas needs to increase by 6.8%, which means that the energy consumption caused by the liquefaction unit needs to be increased by 6.8% during the assessment. If the contract requirements are to be met, not only the rectification of the circulating nitrogen compressor but also the air conditioning should be considered. Improvement of the partial liquefaction unit. In fact, after partial rectification of the air separation unit, the liquid nitrogen production increased by about 10%. When repairing the circulating nitrogen compressor, it was also found that the worm, rotor and bearing were extremely worn, which also caused a significant increase in energy consumption. . Obviously, the results of the analysis are in line with the facts, and this method of checking the energy consumption by means of thermodynamic calculation is also feasible. period Stacking Machine,Automatic Material Collection Stacking Machine,Hardware Collection Equipment,Material Collection Equipment Dongguan City Li you machinery and Equipment Co., Ltd. , https://www.gdliyou.com