With the rapid development of power electronics microelectronics technology, the manufacturing process of high-power rectifier devices has been progressing, the controllable power of the inverter has also been developed to 15, and some even to 1700kW.Inverter in all walks of life has been widely used, Such as our building materials industry grate cooler feeder dosing system. Fan fan fan pump water tower and other equipment speed. Application of frequency control technology, has been used in rotary kiln feeder stacker and other equipment, the economic benefits are significant. Based on years of experience, the following simple talk about the frequency converter installation and commissioning.
Inverter Selection In many brands and types of select the appropriate inverter is very important, and now on the market popular national brands and a lot of series, in addition to common basic functions, there are many unique auxiliary functions and parameters, the first Understand the price and product quality, and secondly, should understand the technical characteristics of the inverter, according to the control object to select the appropriate function of the inverter, from the cost point of view the function can be used on the line, rather than function more as possible, from the following aspects Control methods Inverter according to their different control methods can be divided into general-purpose and engineering two categories. Universal branch go and show. Too humble to, craft got, show. In disguise of the exhibition to use the old for the old, sell ignorance to use to do the younger sister made, change the pouch, the aspect 1 fans, 吣 use 麴 large passenger custard 4 in 61i, to meet the speed requirements of the process, frequency control Speed ?? range of the device are in the range above, and in the ceramic cement production process, the speed range in the range to fully meet the requirements.
However, at low speed, due to the air gap flux, falling, it is difficult to meet the constant power requirements, the universal inverter like to use a given closed-loop control, the dynamic response speed is relatively slow. Internally, the engineering inverter can detect the automatic compensation automatically and keep the good torque characteristics during low speed operation so as to realize the true closed-loop control. The engineering type frequency changer usually has the kind of control way.
The installation form of fixed wall, the power more than 37kW. Book type, power from 0.2 37 so that occupy a relatively small space, the installation can be closely arranged installed chassis type, power 45 200 requires additional circuitry and the overall chassis occupy a larger space. Cabinet type, control power 45 1500 In addition to having the characteristics of installed cabinets, compared with a larger space. Choose according to the controlled motor power and site installation conditions choose the right type.
Voltage and protection level and speed range The inverter voltage level 10230, there are 575,660,690 level, protection level 圯 00 圯 54, should be made according to the specific circumstances of the appropriate choice, from the speed range and degree requirements , The frequency converter has the frequency control, speed control range speed 140000000, we use the FC way to meet the production requirements.
In general, small power inverter is equipped with braking resistor, the system inertia or braking time need not be very short, you do not need to add external resistance, the inertia of the larger and frequent speed or braking time requirements of a short external system Resistance or braking unit.
Inverter installation During the installation process, technical support is the primary ambient temperature does not exceed 4, pay attention to moisture, to ensure the installation of ventilation and cooling, especially the external braking resistor and brake unit, and give full consideration to interference, such as limestone feed fan Pump back to the kiln raw mill and other speed control links, the inverter is relatively decentralized installation, mutual interference is small, does not affect the normal use, and in some production processes such as raw materials, raw materials clinker system requires more than one inverter installed in the electricity Control room with the same control panel, because the inverter itself is a strong source of interference, subharmonics generated during work, interfere with each other and the main control equipment, etc., affecting the normal operation of the system, and control system signal transmission mostly Low-voltage, 5, DC system work properly. In the same control cabinet contactor solenoid valve and other coils should be connected in parallel with the surge absorber, absorber wiring can not exceed 20, otherwise it will play the role of antenna from the power frequency network interference can be connected into the line reactor to be suppressed, It also prevents the inverter from causing harmonic pollution to the power grid.
Practice has proved that the production site conditions are good, in addition to strictly in accordance with the requirements of the source of interference shielding, the control signal transmission should be used current 420, the production side of the poor field conditions, in addition to shielded wire must be used with the inverter sampling and Control signal connection, and the signal line shielding network to do a separate dedicated grounding, which can effectively suppress the interference.
If the distance between the inverter and the motor is over 10, the parasitic capacitance of the cable between the motor and the inverter is too large and acts in conjunction with the parasitic capacitance of the motor’s phase winding. When the inverter is switched on, due to the high speed, Large peak current, deterioration of the inverter operating conditions, and even burn the switch. At the same time, the voltage drop across the long leads also increases, reducing the motor terminal voltage, resulting in an increase in the stator current. In order to solve this problem, the wire cross-sectional area should be enlarged to ensure that the line voltage drop is within 2, at the same time, the inverter output reactor should be installed to compensate the distribution capacitor charging current generated by the long-distance wire. For the selection of output reactor, refer to the instructions of the user’s manual provided by the buccal device manufacturing company.
In the implementation of the above measures are still unavoidable interference affecting the normal use of the system, should consider the replacement of other brands and models of the inverter.
Frequency converter parameter setting and debugging The frequency converter parameter setting and debugging, is the normal operation of equipment, a fundamental guarantee measures, the scene appears many questions, is often asked to set the parameters, but has nothing to do with the device itself, which can be Reasonable and correct setting of the importance of the parameters, the parameters of the ⑷ years of mechanical and electrical States before setting to read the product manual.
The basic parameters of the basic parameters set on the motor nameplate rated power voltage foam speed cheek rate and start braking and control methods. It should be noted here is that the input voltage to be selected according to the supply of the unit, the output frequency according to the production process, and other parameters are set like the inverter has dozens to hundreds of parameters can be set, the actual use of large Most can use the factory settings, only for a few special settings to meet the production requirements. If you want to load the link, you must set the start-up parameter. You can increase the torque by setting two parameters: continuous lift and start-up. The increase torque is valid only at start-up and overlaps with continuous lift. The sum of the points is limited to 250 or less. When the cheek rate reaches the set value, the start-up effect is ended and the start-up requirements of the device are satisfied.
After the initial operation parameters of the equipment have been set, enter the initial operation stage, and carefully check the lines to ensure the correctness of the wiring. The equipment that is not allowed to reverse must be checked and the phase sequence should be checked. To ensure the safety, it is recommended to use the keyboard to manually start the slow start mode, and the concept of equipment operation and output current, a reasonable adjustment of starting and braking time torque and other parameters, and gradually accelerated to rated speed, the normal operation can be put into automatic Way to complete the test run.
Conclusion These are my factory in the transformation process, the use of a large number of inverter summed up the meager experience, we rely on the economic effect is significant, to solve many of the other start-up and scheduling difficult to solve the question, has a very practical value, with very optimistic Prospects.