Voltage transformer faults often occur when high-power heavy-duty VFDs are in use. When the inverter is closed (not started), a fault code is displayed. Regarding the “OC” (fault) problem of the voltage transformer of a high-power frequency converter. In fact, this fault usually only damages one voltage transformer. At this time, you can unplug one in turn and then close it to see if everything is normal. Whichever one is damaged cannot be connected properly. A non-closed-loop inverter can use two output voltage transformers.

VFDs with an output power above 22W sometimes trip “OXH” fault and the operation of the frequency converter is not affected.

Check the temperature and current of the cooling fan and inverter according to the instructions. They are all normal. I can’t tell what is going on! After inspection, it is actually a three-wire (including detection line) located inside the inverter (on top of the module). The cooling fan is broken. Sometimes the cooling fan can run but too much dust will cause the inverter to display this fault. Because the cooling fan of the inverter’s heat sink is normal, most people don’t know that there is a cooling fan inside the inverter, which leads to many people being deceived. Therefore, maintenance personnel must first check the inside of the inverter (not the cooling fan seen outside)

Ten VFD Parameters

If the conformal anti-paint of the circuit board is damaged, it must be handled properly.

When repairing the circuit board of the inverter, the conformal paint on the circuit board is damaged due to the removal of components. Many people do not spray conformal paint on the circuit board after repairing the inverter. As a result, the circuit board (especially the power transformer) becomes damaged. When the weak current part is exposed to excessive dust or dust, many faults are likely to occur. If you don’t have conformal paint, you can use rosin dissolved in ethanol to brush out the circuit board, and then dry it with a hair dryer.

Raise the fuse tube in the inverter power circuit

Some brands of inverter power transformers are not equipped with fuse tubes. When the switch tube is damaged and short-circuited, the primary winding of the power transformer is often burned out. Some inverter power transformers are difficult to find and the price is high. In order to better maintain the transformer, the general method is to disconnect the control loop between the switch tube and the primary winding of the transformer on the circuit board, and weld a fuse tube (5A) or a 0.6~1/1W resistor to the wound. . In this way, if the switch tube fails in a short circuit, the transformer will be fine.

Calibration of main parameters to deal with some difficult problems and faults of the inverter

Some counterfeit inverters have poor anti-interference ability. After operating for a period of time, false alarms (such as current, load, overvoltage, etc.) will often appear. Some will fail to start or stop for no reason. Most of these are due to communication problems. A program flow error occurs. During such instances, it’s possible to reset the primary parameters of the inverter to their factory defaults. The act of “restoring main parameters to factory values” is often regarded as a versatile solution and is frequently employed during inverter inspections. However, it can sometimes result in the inverter displaying communication faults. If you encounter a situation where the primary parameters cannot be accessed, it is typically due to a malfunctioning memory in the frequency converter. If replacing the memory doesn’t resolve the issue, then the motherboard will need to be replaced.

In most cases, a burnt IGBT module will harm components in the drive circuit, especially the Zener diode and the photocoupler. Conversely, if there are issues with the drive circuit’s components, such as small capacitors leaking or becoming brittle, it can also lead to IGBT module burnouts or imbalances in the inverter’s output voltage. To check for problems in the drive circuit, you can compare open-end resistors when the power is disconnected to ensure their consistency. Once the power is connected, you can compare the open-end voltage waveform after startup (although some inverters require modules for starting). It’s advisable to install a dummy load during inspection to prevent accidental module damage from contact with other lines. The overvoltage protection of the frequency converter only halts the output and does not safeguard the converter itself from harm.

Voltage transformer faults often occur when high-power heavy-duty VFDs are in use. When the inverter is closed (not started), a fault code is displayed. Regarding the “OC” (fault) problem of the voltage transformer of a high-power frequency converter. In fact, this fault usually only damages one voltage transformer. At this time, you can unplug one in turn and then close it to see if everything is normal. Whichever one is damaged cannot be connected properly. A non-closed-loop inverter can use two output voltage transformers.

VFDs with an output power above 22W sometimes trip “OXH” fault and the operation of the frequency converter is not affected.

Check the temperature and current of the cooling fan and inverter according to the instructions. They are all normal. I can’t tell what is going on! After inspection, it is actually a three-wire (including detection line) located inside the inverter (on top of the module). The cooling fan is broken. Sometimes the cooling fan can run but too much dust will cause the inverter to display this fault. Because the cooling fan of the inverter’s heat sink is normal, most people don’t know that there is a cooling fan inside the inverter, which leads to many people being deceived. Therefore, maintenance personnel must first check the inside of the inverter (not the cooling fan seen outside)

Ten VFD Parameters

If the conformal anti-paint of the circuit board is damaged, it must be handled properly.

When repairing the circuit board of the inverter, the conformal paint on the circuit board is damaged due to the removal of components. Many people do not spray conformal paint on the circuit board after repairing the inverter. As a result, the circuit board (especially the power transformer) becomes damaged. When the weak current part is exposed to excessive dust or dust, many faults are likely to occur. If you don’t have conformal paint, you can use rosin dissolved in ethanol to brush out the circuit board, and then dry it with a hair dryer.

Raise the fuse tube in the inverter power circuit

Some brands of inverter power transformers are not equipped with fuse tubes. When the switch tube is damaged and short-circuited, the primary winding of the power transformer is often burned out. Some inverter power transformers are difficult to find and the price is high. In order to better maintain the transformer, the general method is to disconnect the control loop between the switch tube and the primary winding of the transformer on the circuit board, and weld a fuse tube (5A) or a 0.6~1/1W resistor to the wound. . In this way, if the switch tube fails in a short circuit, the transformer will be fine.

Calibration of main parameters to deal with some difficult problems and faults of the inverter

Some counterfeit inverters have poor anti-interference ability. After operating for a period of time, false alarms (such as current, load, overvoltage, etc.) will often appear. Some will fail to start or stop for no reason. Most of these are due to communication problems. A program flow error occurs. During such instances, it’s possible to reset the primary parameters of the inverter to their factory defaults. The act of “restoring main parameters to factory values” is often regarded as a versatile solution and is frequently employed during inverter inspections. However, it can sometimes result in the inverter displaying communication faults. If you encounter a situation where the primary parameters cannot be accessed, it is typically due to a malfunctioning memory in the frequency converter. If replacing the memory doesn’t resolve the issue, then the motherboard will need to be replaced.

In most cases, a burnt IGBT module will harm components in the drive circuit, especially the Zener diode and the photocoupler. Conversely, if there are issues with the drive circuit’s components, such as small capacitors leaking or becoming brittle, it can also lead to IGBT module burnouts or imbalances in the inverter’s output voltage. To check for problems in the drive circuit, you can compare open-end resistors when the power is disconnected to ensure their consistency. Once the power is connected, you can compare the open-end voltage waveform after startup (although some inverters require modules for starting). It’s advisable to install a dummy load during inspection to prevent accidental module damage from contact with other lines. The overvoltage protection of the frequency converter only halts the output and does not safeguard the converter itself from harm.

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