The energy feedback unit supplier reminds you to choose the appropriate inverter for the size of the motor, sometimes even up to one size. A high-power inverter has a lower power factor, so it is better to install an AC reactor at the input end of the inverter.
This is to improve the power factor and suppress high-frequency harmonics. If starting and braking frequently, it is necessary to install a braking unit and braking resistor.
If you need to reduce noise, you can choose a water-cooled frequency converter; If braking is required, it is necessary to select a power chopper and braking resistor. Alternatively, four quadrant products can be selected to provide energy feedback to the grid and save energy; If there is only a DC power supply on site, a simple inverter product (using a DC power supply) can be chosen to drive the motor.
The basis for selecting a frequency converter is that the current curve of the frequency converter includes the current curve of the mechanical load. Here are some practical issues that we need to pay attention to when choosing a frequency converter.
1. The purpose of using frequency conversion; Constant voltage control or constant current control, etc.
2. Load type of frequency converter; For pumps such as vane pumps or volumetric pumps, special attention should be paid to the performance curve of the load, as the performance curve determines the method of application.
3. Matching problem between frequency converter and load;
Voltage matching: The rated voltage of the frequency converter matches the rated voltage of the load.
Current matching: For ordinary centrifugal pumps, the rated current of the frequency converter matches the rated current of the motor. For special loads such as deep water pumps, it is necessary to refer to the motor performance parameters to determine the inverter current and overload capacity with high current.
Torque matching: This situation may occur under constant torque loads or with deceleration devices.
When using a frequency converter to drive a high-speed motor, due to the low reactance of the motor, the increase in high-order harmonics leads to an increase in the output current value. Therefore, the selection of frequency converters for high-speed motors should have a capacity slightly larger than that of ordinary motors.
If the frequency converter needs to operate with a long cable, measures should be taken to suppress the influence of the long cable on the ground coupling capacitance and avoid insufficient output of the frequency converter. Therefore, in this case, the capacity of the frequency converter should be increased by one level or an output reactor should be installed at the output end of the frequency converter.
6. For some special application scenarios, such as high temperature and altitude, it may cause the frequency converter to reduce its capacity, and the frequency converter capacity should be increased by one gear.
Of course, in situations where strict requirements are placed on motor motion control systems, it is necessary to accurately test the effectiveness of the frequency converter selection. The direct method is to conduct testing through a motor testing system. But in order to complete the overall testing of the frequency converter and motor system, higher requirements have been put forward for the motor testing system, such as high bandwidth, high-precision electrical parameter measurement, multi-channel synchronous testing, etc. Have you learned? I hope this article can be helpful to everyone. If you want to learn more related information, you can continue to follow us.