How to wire a frequency converter ? This is a common problem that many people encounter. Below, we will use diagrams to teach you how to quickly master the simple wiring method for frequency converters.
The image above is a wiring diagram for a frequency converter. There are several points to note during the installation of a frequency converter. For example, the frequency converter itself has strong electromagnetic interference, which can interfere with the operation of some equipment. Therefore, we can add cable sleeves to the output cables of the frequency converter. Also, the control lines inside the frequency converter or control cabinet should be at least 100mm away from the power cables, etc.
Inverter wiring method
I. Wiring of the main circuit
1. The power supply should be connected to the R, S, T terminals of the inverter input, and never to the output terminals (U, V, W), otherwise the inverter will be damaged. After wiring, all loose wire ends must be cleaned up. Loose wire ends may cause abnormalities, malfunctions, and failures; the inverter must always be kept clean. When drilling holes on the control panel, be careful not to let debris or dust 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.
