Inverter repair detection cheats method - Solutions - Huaqiang Electronic Network

GW MB10F 0.8A 1000V rectifier bridge

Probe current voltage pin 420*4450 head diameter 5.0 over current current and voltage pin

L0504-Murata muRata common mode inductor 90Ω 150mA

Frequent maintenance problems in the daily maintenance of the inverter, such as poor peripheral parameter setting or mechanical failure. If the inverter is faulty, how to determine which part of the problem is involved is briefly introduced here.
First, static testing
1. Test the rectifier circuit to find the P and N terminals of the internal DC power supply of the inverter, adjust the multimeter to the resistance X10 file, the red bar to the P, and the black bar to the R, S, T, respectively. The resistance of Europe is basically balanced. Instead, the black bar is connected to the P terminal, and the red bar is sequentially connected to R, S, and T, and has a resistance close to infinity. The red bar is connected to the N-end and the above steps are repeated. The same result should be obtained. If there are the following results, it can be determined that the circuit has an abnormality, A. The three-phase resistance is unbalanced, which can explain the rectifier bridge failure. B. When the red bar is connected to the P terminal, the resistance is infinite, and it can be concluded that the rectifier bridge is faulty or the starting resistor is faulty.
2. Test the inverter circuit and connect the red watch to the P-side black bar to connect U, V, W respectively. There should be several ohms of resistance, and the resistance values ​​of the phases are basically the same, and the inversion should be infinite. Connect the black bar to the N terminal. Repeat the above steps to get the same result. Otherwise, the inverter module can be determined. 2. Dynamic test After the static test result is normal, the dynamic test can be performed, that is, the power test machine. The following points must be noted before and after power-on:
1. Before power-on, you must confirm whether the input voltage is wrong. If the 380V power supply is connected to the 220V inverter, there will be a bomber (fried capacitor, varistor, module, etc.).
2. Check if the sockets of the inverter are connected correctly. If there is any loose wire, the connection may be abnormal, which may cause the inverter to malfunction. In severe cases, the machine may explode.
3. After the power is turned on, the fault display content is detected and the fault and the cause are preliminarily determined.
4. If the fault is not displayed, first check whether the parameter is abnormal and return the parameter after no-load (no motor) to start the inverter and test the U, V, W three-phase output voltage value. If there is a phase loss, three-phase unbalance, etc., the module or the drive board is faulty.
5, in the case of normal output voltage (no phase loss, three-phase balance), load test. When testing, it is best to test at full load.
Third, fault judgment
1. The rectifier module is generally damaged due to the grid voltage or internal short circuit. Replace the rectifier bridge with the internal short circuit removed. When dealing with faults on site, it is important to check the user's power grid conditions, such as grid voltage, and whether there are equipment such as welding machines that are polluting the power grid.
2. Inverter module damage is generally caused by motor or cable damage and drive circuit failure. After repairing the drive circuit, the drive waveform is replaced and the module is replaced. After replacing the engine board in the field service, you must also check the motor and connecting cables. Run the frequency converter without any faults.
3. No display after power-on is generally caused by damage to the switching power supply or damage to the pre-charging circuit, so that the DC circuit is not caused by DC voltage. If the starting resistor is damaged, the panel may be damaged.
4. After the power is turned on, the overvoltage or undervoltage is generally caused by the input phase loss, the aging of the circuit and the moisture of the circuit board. Find out its voltage detection circuit and detection points and replace the damaged device.
5. Overcurrent or ground short circuit after power-on is generally caused by damage to the current detection circuit. Such as Hall components, op amps, etc.
6, start display over current is generally caused by damage to the drive circuit or inverter module.
7. No-load output voltage shows overload or over-current after normal load. This kind of situation is generally caused by improper parameter setting or damage to the aging module of the drive circuit.