How to choose the right frequency converter for the motor
The frequency converter enables the motor drive system to achieve smoother operation of the motor and control the working state of the motor, avoiding manpower. However, the problem faced by engineers is: There are many types of motor loads, and the performance requirements of the corresponding frequency converters are also different. How can I choose a suitable frequency converter for the motor? Jact-High performance Vector AC drive firm, and also China DC servo motor Agent. It summarizes how to choose the right inverter for the motor.
The selection of frequency converter should be considered in accordance with the type of construction machinery, speed range, static speed accuracy, starting torque, etc., so that it not only meets the process and production requirements, but also is easy to use and economical. In most cases, the size of the frequency converter is selected according to the size of the motor, and the size of the frequency converter is selected for the size of the motor, and sometimes it can be a larger size.
The high-power frequency converter has a low power factor, so install an AC resistor at the input end of the frequency converter. This not only improves the power factor but also suppresses high-frequency harmonics. If you start and brake frequently, install a brake unit and a brake resistor.
Listed below are some 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. The load type of the frequency converter; such as vane pump or positive displacement pump, etc. Special attention should be paid to the performance curve of the load, which determines the method of application.
3. The matching problem of frequency converter and load;
Voltage matching; the rated voltage of the frequency converter load matches.
Current matching; for ordinary centrifugal pumps, the rated current of the frequency converter motor is the same. For special loads, it is necessary to refer to the motor performance parameters to determine the frequency converter current and overload capacity.
Torque matching; this situation may occur under constant torque load or when there is a deceleration device.
4. When using a frequency converter to drive a high-speed motor, the small reactance of the high-speed motor and the increase of higher harmonics will cause the output current value to increase. Therefore, when selecting a frequency converter for a high-speed motor, its capacity is larger than that of an ordinary motor.
5. If the frequency converter needs to run with a long cable, effective measures should be taken at this time to suppress the impact of the long cable on the ground coupling capacitance and avoid insufficient output of the frequency converter. At this time, install an output reactor at the output of the frequency converter or Increase the capacity of frequency converter by one file.
6. For some special occasions such as high temperature and high altitude, the frequency converter will be derated, and the capacity of the frequency converter should be enlarged by one gear.
For some occasions that have strict requirements on the motor motion control system, it is necessary to accurately detect the selection effect of the frequency converter. The direct method is to test through the motor test system.