Precautions for energy-saving frequency conversion renovation of air compressors

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The last edit to this post was made by zgj2405 on 2009-9-22 at 21:15. 1. Selection of inverter capacity: Before deciding on the capacity of the inverter, it is necessary to measure the maximum load current of the oil pump motor when it operates at its normal frequency during various stages of the air compressor’s operation; this value should be used as a basis for selecting the appropriate inverter capacity. The rated current of the inverter should preferably be 1.1 to 1.5 times the rated current of the motor it controls, and its voltage level should match that of the motor. 2. Installation environment of the frequency converter: Due to the high temperatures and large amounts of plastic dust in plastic factories, the cabinet of the energy-saving device must be properly designed. Sufficient space should be left near the frequency converter inside the cabinet to ensure good ventilation, and cooling fans should be installed to enable forced air cooling. It should be installed on-site in a well-ventilated area, away from heat sources and areas with a lot of dust. 3. Perfectly integrate injection molding machine technology with inverter technology: Send engineers who are knowledgeable both in injection molding machine technology and inverter technology to the site to gain a detailed understanding of the operating conditions of the injection molding machines as well as the way in which the control systems function. Minimizing changes to the injection molding machine’s original control system, and selecting control signals wisely to perfectly integrate injection molding technology with inverter technology, are the conditions for a successful energy-saving transformation of such machines. 4. Regarding the selection of frequency converters, it should be determined based on the nature and requirements of the load. Since the load characteristic of injection molding machines is of the constant torque type, with relatively stiff mechanical properties and high requirements for dynamic performance, vector-controlled high-performance frequency converters should be used. 5. Interference of frequency converters on the operation of injection molding machines: Both the input and output currents of frequency converters contain a certain amount of high-order harmonic components, which, when transmitted, create signals that interfere with the proper operation of the injection molding machine. The following measures should be taken: (1) Install special filters and reactors for inverters on the input and output sides of the inverter in order to reduce high-order harmonic currents ； (2) The enclosure of the frequency converter must be reliably grounded. (3) Do not run the input and output cables of the inverter parallel to the control signals of the inverter (including the control signal wires of other devices), nor tie them together ； (4) Reduce the carrier frequency of the inverter ；