Generally speaking, a frequency converter can have a service life of up to 10 years under reasonable application conditions. But you have to understand one thing, the influence of various external factors in the industrial environment is basically unavoidable, the service life. Various failures of the VFD will shorten the service life of the VFD. In fact, the IC short circuit fault of VFD is easy to deal with and will not affect the service life of VFD.

When the VFD has an IC short circuit, the switching power supply will oscillate frequently, and the operation display panel will turn on and off. This is a typical failure of the switching power supply overload or short circuit. Due to the abnormal load, the current detection circuit of the switching power supply takes a protective action, so that the switching power supply will continue to be in a state of frequent oscillation.

vfd fault science

IC short-circuit detection methods include the following: VFD disconnects the load circuits one by one to check which load circuit the VFD short-circuit fault is in, or after the power is cut off, test the output of each power supply to see if the resistance value is reduced or short-circuited. Measuring both ends of the +5V power supply shows a small resistance of 7.8Ω, while the normal circuit resistance is about several hundred Ω. Judging that there is a short circuit in the +5V load circuit. After disconnecting the +5V load circuit, if the output of the switching power supply is relatively stable, it means that the fault is in the +5V load circuit. +5V power supply from the cable terminal to the CPU motherboard, for the CPU chip and peripheral circuits. The circuit range is relatively wide. There are more integrated circuits with +5V power supply on the CPU motherboard, reaching more than 20 pieces. If the VFD short circuit fault is detected through normal troubleshooting, it is necessary to pick out the +5V power supply pin of each IC circuit and check the resistance value of the power supply output. When picking up an IC power supply pin, the resistance value of the power supply output is 7.8Ω.

We cannot predict how many ICs will need to be opened until we find the real faulty IC. Moreover, because the CPU components are welded more precisely, the maintenance difficulty is almost the same as that of the mobile phone circuit board, especially when the IC circuits are mostly chip components. It is not an exaggeration to say that the copper foil strips of IC pins are thinner than a human hair. Therefore, if you accidentally cut off the copper foil strip, it will be difficult to connect it again. So even if it’s a stupid way to pick one by one, you’d better do it honestly.

Considering the limited load capacity of the switching power supply, when the faulty circuit is connected, the overcurrent protection may be triggered to stop the output of the switching power supply. Therefore, use an external +5V power supply with a larger capacity, and connect a 5ω 5W current-limiting resistor in series on the CPU motherboard. After a few minutes after startup, check the IC chips on the CPU main board. After a simple manual touch inspection, you can find which chips have abnormal temperature rise. These ICs with abnormal temperatures are broken components.

Generally speaking, a frequency converter can have a service life of up to 10 years under reasonable application conditions. But you have to understand one thing, the influence of various external factors in the industrial environment is basically unavoidable, the service life. Various failures of the VFD will shorten the service life of the VFD. In fact, the IC short circuit fault of VFD is easy to deal with and will not affect the service life of VFD.

When the VFD has an IC short circuit, the switching power supply will oscillate frequently, and the operation display panel will turn on and off. This is a typical failure of the switching power supply overload or short circuit. Due to the abnormal load, the current detection circuit of the switching power supply takes a protective action, so that the switching power supply will continue to be in a state of frequent oscillation.

vfd fault science

IC short-circuit detection methods include the following: VFD disconnects the load circuits one by one to check which load circuit the VFD short-circuit fault is in, or after the power is cut off, test the output of each power supply to see if the resistance value is reduced or short-circuited. Measuring both ends of the +5V power supply shows a small resistance of 7.8Ω, while the normal circuit resistance is about several hundred Ω. Judging that there is a short circuit in the +5V load circuit. After disconnecting the +5V load circuit, if the output of the switching power supply is relatively stable, it means that the fault is in the +5V load circuit. +5V power supply from the cable terminal to the CPU motherboard, for the CPU chip and peripheral circuits. The circuit range is relatively wide. There are more integrated circuits with +5V power supply on the CPU motherboard, reaching more than 20 pieces. If the VFD short circuit fault is detected through normal troubleshooting, it is necessary to pick out the +5V power supply pin of each IC circuit and check the resistance value of the power supply output. When picking up an IC power supply pin, the resistance value of the power supply output is 7.8Ω.

We cannot predict how many ICs will need to be opened until we find the real faulty IC. Moreover, because the CPU components are welded more precisely, the maintenance difficulty is almost the same as that of the mobile phone circuit board, especially when the IC circuits are mostly chip components. It is not an exaggeration to say that the copper foil strips of IC pins are thinner than a human hair. Therefore, if you accidentally cut off the copper foil strip, it will be difficult to connect it again. So even if it’s a stupid way to pick one by one, you’d better do it honestly.

Considering the limited load capacity of the switching power supply, when the faulty circuit is connected, the overcurrent protection may be triggered to stop the output of the switching power supply. Therefore, use an external +5V power supply with a larger capacity, and connect a 5ω 5W current-limiting resistor in series on the CPU motherboard. After a few minutes after startup, check the IC chips on the CPU main board. After a simple manual touch inspection, you can find which chips have abnormal temperature rise. These ICs with abnormal temperatures are broken components.

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