Understand the basic principles and functions of inverter filters
The main function of inverter filters is to reduce electromagnetic interference (EMI) generated by the inverter and improve the stability and reliability of the system.
Select a suitable inverter filter
Select the appropriate filter based on the inverter's power, frequency, and application scenario.
Check the specifications and parameters of the inverter filter.
Confirm that the filter's input/output voltage, current, frequency, and other parameters match the inverter and load.
Prepare wiring tools and materials
Prepare appropriate wiring tools, such as screwdrivers, wire strippers, and terminal blocks.
Disconnect the power
Before wiring, ensure that the power supply to the inverter and filter is disconnected to ensure safety.
Determine the wiring location
Determine the wiring locations based on the layout of the frequency converter and filter.
Wiring steps
a. Connect the input power cord
Connect the input power cord to the input terminal of the frequency converter.
b. Connect the output cable
Connect the output line to the output terminal of the frequency converter.
c. Connect the filter input line
Connect the filter's input line to the inverter's output terminal.
d. Connect the filter output line
Connect the filter's output line to the load's input terminal.
e. Grounding
Ensure that the grounding wires of the frequency converter and filter are connected to a common grounding point.
Check wiring
Before powering on, carefully check that the wiring is correct and secure.
Power-on test
After powering on, observe the operating status of the frequency converter and filter to ensure stable system operation.
Troubleshooting
If any abnormalities are found, such as overheating, noise, or vibration, promptly investigate the cause of the malfunction and repair it.
Maintenance and upkeep
Regularly check the filter's connection status to ensure it is working properly.
Safety Precautions
During operation, follow safety procedures to avoid dangers such as electric shock and short circuits.
The correct wiring method for the inverter filter is as follows:
I. Wiring of the main circuit
1. The power supply should be connected to the R, S, and T terminals of the inverter input. Never connect it to the output terminals (U, V, W), otherwise the inverter will be damaged. After wiring, all loose wire ends must be thoroughly cleaned. Loose wire ends can cause abnormalities, malfunctions, and failures; the inverter must always be kept clean. When drilling holes in the control panel, be careful not to allow debris or dust to enter the inverter.
2. Do not connect anything other than the recommended braking resistor option between terminals + and PR, or short-circuit it under any circumstances.
3. Electromagnetic interference: The inverter's input/output (main circuit) contains harmonic components, which may interfere with nearby communication equipment. Therefore, installing optional radio noise filters FR-BIF, FRBSF01, or FR-BLF line noise filters can minimize interference.
4. During long-distance cabling, the parasitic capacitance charging current of the cabling can reduce the fast response current limiting function, causing malfunctions in instruments connected to the secondary side. Therefore, the maximum cabling length should be less than the specified value. If the cabling length must be exceeded, Pr.156 should be set to 1.
5. Do not install power capacitors, surge suppressors, or radio noise filters on the output side of the frequency converter. Otherwise, it will cause frequency converter failure or damage to the capacitors and surge suppressors.
6. To keep the voltage drop within 2%, use appropriate wires for wiring. When the wiring distance between the frequency converter and the motor is long, especially under low-frequency output conditions, the motor torque will decrease due to the voltage drop in the main circuit cable.
7. After operation, any changes to the wiring must be made only after the power has been disconnected for at least 10 minutes and the voltage has been checked with a multimeter. For a period of time after power is off, dangerously high voltage may still be present on the capacitors.
II. Wiring of the control circuit
The control circuits of frequency converters can be broadly divided into two types: analog and digital.
1. Shielded or twisted-pair cables should be used for wiring the control circuit terminals, and they must be wired separately from the main circuit and high-voltage circuit (including 200V relay program circuit).
2. Since the frequency input signal of the control circuit is a small current, in the case of contact input, in order to prevent poor contact, two parallel nodes or double contacts should be used for the small signal contacts.
3. For the wiring of the control circuit, cables with a diameter of 0.3 to 0.75 square meters are generally selected.
III. Ground wire connection
1. Due to leakage current in the frequency converter, the frequency converter and motor must be grounded to prevent electric shock.
2. Use a dedicated grounding terminal for the frequency converter. For grounding wire connections, use tin-plated crimp terminals. When tightening the screws, be careful not to damage the screw threads.
3. Tin plating does not contain lead.
4. Use a thicker wire diameter for the grounding cable, which must be equal to or greater than the specified standard. The grounding point should be as close as possible to the frequency converter, and the grounding wire should be as short as possible.
**Inverter wiring precautions:**
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1. The frequency converter itself has strong electromagnetic interference, which can interfere with the operation of some equipment. Therefore, we can add a cable sleeve to the output cable of the frequency converter.
2. The control lines inside the frequency converter or control cabinet should be at least 100mm away from the power cables, etc.
