Simply and quickly use a multimeter to measure the quality of the inverter
1. Use a multimeter to measure whether the frequency converter is good or bad
1. Find the P (+) and N (-) terminals of the DC power supply inside the inverter, adjust the multimeter to the diode gear, put the black test lead on the P (+) of the inverter, and measure the three phases of R, S, and T in turn with the red test lead The three-phase numbers are the same and basically balanced, indicating that the frequency conversion is good. If the measured values are not the same, it indicates that the inverter module is damaged.
2. Find the P (+) and N (-) terminals of the DC power supply inside the inverter, adjust the multimeter to the diode gear, put the red pen on the N (-) of the inverter, and measure U, V, W respectively with the black pen. If the phase numbers are the same and basically balanced, it means that the frequency conversion is good. If the measured values are not the same, it means that the inverter module is damaged.
1). Remove the R, S, T terminals U, V, W terminals of the inverter to automatically resist the resistance when checking whether the inverter module is good or bad.
2). The same method can be used to measure the quality of various frequency converters.
3). If the inverter reports overvoltage and undervoltage, check whether the inverter module is damaged, and use the above method to measure whether the inverter is good or bad.
4). Sometimes the inverter module may be damaged if the main switch is tripped. Don’t rush to power on, and use the above method to measure the quality of the inverter.
2. Measurement of DC bus voltage
1. Measurement purpose: When the inverter reports phase loss or undervoltage, and there is no problem in measuring the input voltage, measure this voltage to determine which circuit inside the inverter has a problem.
2. Measuring instrument: DC voltmeter, choose 1000V DC gear.
3. Measurement method: connect the red test lead to the point P of the DC bus (there are corresponding terminals), connect the black test lead to the point N, and read out the measured voltage value. According to the principle of rectification, the frequency converter should be measured under load. Only by measuring under load can you see whether the voltage is low. When the voltage under load is lower than 470V, the capacity of the filter capacitor decreases, and if it is lower than 400V, there is a phase loss.
