1. Find the P(+) end and N(-) end of the DC power supply inside the frequency inverter, adjust the multimeter to the diode black watch pen on the inverter P(+), and the red watch pen measures R, S, and T three phases respectively with the same and basic balance, indicating that the frequency conversion is good, such as the measured values are not the same, indicating that the frequency invertermodule is damaged.

2.Find the P(+) end and N(-) end of the DC power supply inside the frequency inverter, adjust the multimeter to the diode red pen on the frequency inverter N(-), and the black pen measures the U, V, and W three-phase numbers in turn and basically balance, indicating that the frequency conversion is good, such as the measured values are not the same, indicating that the frequency converter module is damaged.

3.Note

Remove the frequency inverter R, S, T terminal U, V, W terminal automatic resistance when detecting the inverter module.

The same method can be used to measure the quality of various inverter.

If the inverter reports overvoltage and undervoltage, check whether the inverter module is damaged and measure the inverter with the above method.

Sometimes the jump switch may be damaged frequency converter module, do not hurry to power on, use the above method to measure the frequency converter is good or bad.

4.Dc bus voltage measurement

The purpose of measurement: when the frequency inverter reports the lack of phase, undervoltage, the measurement of the input voltage is no problem, measure this voltage, to determine which circuit is the problem inside the inverter.

Inventory: dc voltmeter, choose 1000 v dc block.

Measurement methods: red pens and dc bus point P (with corresponding terminals), black pens and pick N points, read voltage measurement. According to the principle of rectification, the inverter should be measured under load. Only when measured under load can you see if the voltage is low. The voltage under load is lower than 470V, the filter capacitance is reduced to less than 400V, and the phase is missing.