Three groups of asynchronous AC motors commonly used in injection molding machines cannot change speeds, and the amount of dragged quantitative vane pump and output hydraulic oil cannot be changed. When the injection molding machine is performing low-speed operation, excess flow is returned to the tank via the relief valve, causing a large loss of energy. The frequency converter can adjust the speed of the motor according to the instructions of the control system, so that the flow rate of the hydraulic oil output by the vane pump can be changed according to the speed requirement of the injection molding machine, thereby reducing the energy consumption of the hydraulic oil flowing back from the overflow valve to the fuel tank, thereby saving a lot of energy Electric energy. According to different injection molding products, real-time monitoring of motor power consumption, energy saving rate of 20 to 70%. 2, to avoid personal safety accident After the injection molding machine to install the frequency converter, because the operator took the pieces on the mold, cleaning and repairing the mold, the computer speed simulation of the computer output, the motor is in a stopped state, the hydraulic system is no pressure, to avoid The mechanical misuse completely eliminated the personal safety accidents of the injection molding machine. 3, the soft start power frequency condition of the motor is to use the star triangle step-down delay start, this time the current is 4 to 7 times the rated current of the motor, if more than one high-power motor is started at the same time, it will cause a great impact on the power grid . With variable frequency speed regulation, the motor can be soft started only at the rated current, and the current is smooth without impact, reducing the impact of the starting current on the motor and the power grid, and prolonging the service life of the motor. 4. Reducing Reactive Power The reactive power not only increases the line loss and heat generation of the equipment, but also mainly because the reduction of the power factor leads to the reduction of the active power of the grid. The use of variable frequency speed control energy-saving control device, due to the role of the filter capacitor in the inverter, making the power factor close to 1, increasing the active power of the grid, thus saving the energy of reactive power consumption. Second, the frequency converter in the injection molding machine energy saving application problems and solutions 1. After the injection molding machine is installed with variable frequency speed regulation, the main motor speed changes with the speed of each action of the injection molding machine. The cycle time of the injection molding production cycle is short, and the frequent rotation of the operation causes the main motor to be frequently in the acceleration and deceleration process. The longer acceleration/deceleration response time of the motor leads to an increase in the injection cycle time and a decrease in productivity. Watson VSI9000-ZS/ZG injection molding machine special inverter / inverter integrated cabinet, can be controlled with the injection molding machine computer, through the computer to the inverter control, to achieve the inverter output frequency and output torque decoupling adjustment, to achieve The best cooperation between frequency converter and each action in the injection molding process solves the bottleneck of the injection molding machine's application of variable frequency energy-saving technology leading to a decrease in production efficiency. 2. As the motor speed decreases, the speed of the fan blades connected to the rotor of the motor also decreases, resulting in poor heat dissipation of the motor. In addition, the insulating layer reduces the insulation effect under the impact of inverter frequency conversion voltage. At present, motor manufacturers have specialized production of variable frequency motor, which is to improve these two points, the motor fan is independent of the rotor, the speed is not affected by the motor speed reduction, the insulation layer also uses a more excellent material, which solves the frequency conversion Affect the life of the motor. 3. When the vane pump works, it mainly depends on the high-speed rotating rotor to throw out the vane so as to achieve the purpose of oil absorption. If the rotor speed is reduced, the blades will not have enough centrifugal force to effectively compress the stator surface, so that the internal leakage of the pump will increase and the efficiency will be significantly reduced. When the rotation speed is lower than a certain critical value (such as 400r/min), the vane pump The oil-absorbing ability becomes worse, and even oil cannot be produced. When this problem occurs, the frequency setting signal gain must be increased. In addition, the development of the internal gear pump will gradually replace the vane pump to become the mainstream of the development of the injection molding machine oil pump, so as to solve the problem of poor low-speed oil absorption of the vane pump. 4. When the high pressure mode and slow mode open, the inverter runs under the condition of low speed and high torque, the current easily exceeds the rated value and causes over current protection. The input end of the inverter produced by our company is equipped with mode locking and mold opening. The input point is connected with the output point of mold clamping and mold opening of the injection molding machine computer. Through the special software of the frequency converter, the motor can maintain high speed operation during mold opening and mode locking, avoiding the appearance of low speed and large torque.
1, energy saving