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长沙市开福区北辰三角洲凤凰天阶苑B1E1区2栋35040 Address: Building 2, Block B1E1, Phoenix Tianjie Garden, Beichen Delta, Kaifu District , Changsha 35040
How to select Rockwell AB inverters ?
During work, some customers often fall into the distress of inverter selection. In fact, before selecting a model, you can first understand the working principle of the inverter.
The frequency converter is an electric energy control device that uses the on-off effect of power semiconductor devices to convert a commercial frequency power supply to another frequency. The frequency converter we use now mainly adopts the AC-DC-AC method (VVVF frequency conversion or vector control frequency conversion). First, the power frequency AC power is converted into DC power through a rectifier, and then the DC power is converted into a frequency and voltage controllable AC power to the motor. The circuit of the inverter is generally composed of four parts: rectification, intermediate DC link, inverter and control. The rectifier part is a three-phase bridge-type uncontrollable rectifier, the inverter part is an IGBT three-phase bridge inverter, and the output is a PWM waveform. The intermediate DC link is filtering, DC energy storage, and buffered reactive power.
Therefore, the following points should be determined when selecting Rockwell AB inverters:
1) The purpose of frequency conversion; constant voltage control or constant current control.
2) Load type of the inverter; such as vane pump or positive displacement pump. Pay special attention to the performance curve of the load. The performance curve determines the method and method of application.
3) The matching problem between inverter and load;
I. Voltage matching; the rated voltage of the inverter matches the rated voltage of the load.
II. Current matching; for ordinary centrifugal pumps, the rated current of the inverter is consistent with the rated current of the motor. For special loads, such as deep-water pumps, you need to refer to the motor performance parameters to determine the inverter current and overload capacity with the maximum current. III. Torque matching; this situation may occur under constant torque load or with a reduction gear.
4) When the inverter is used to drive high-speed motors, the output current value increases due to the small reactance of high-speed motors and the increase of higher harmonics. Therefore, the selection of the inverter used for high-speed motors has a slightly larger capacity than the selection of ordinary motors.
5) If the inverter needs to run with a long cable, measures must be taken at this time to suppress the influence of the long cable to the ground coupling capacitor to avoid insufficient output of the inverter, so in this case, the capacity of the inverter should be enlarged by one gear or An output reactor is installed at the output end.
6) For some special applications, such as high temperature and high altitude, the inverter will be derated at this time, and the inverter capacity must be enlarged by one gear.
Hunan Hillray Electric Technology Co., Ltd. Record number: Hunan ICP No. 16017533-1
Phone: 0731-85578889-805 Fax: 0731-85578889-802
Contact: Manager Tang Mobile: 18182102868
Address: Building 2, Block B1E1, Phoenix Tianjie Garden, Beichen Delta, Kaifu District, Changsha 35040
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