ABB inverter repair case

Recently, our team was contacted by a customer who had an ACS800/110KW inverter on-site. After running for some time, the inverter started displaying the ACS800 TEMP fault, and the issue couldn't be resolved even after multiple attempts to reset it. Upon receiving this urgent request, our engineer quickly headed to the site to investigate the problem.

Inspection Process:

Once at the site, we began by disassembling the inverter. We thoroughly checked the rectifier and inverter modules, testing the diode characteristics. With the inverter powered up, the display appeared normal, and the three-phase output voltage was balanced. However, after running under load for half an hour, the inverter again displayed the ACS800 TEMP fault. Here's what the fault means:

1. Check the external ambient temperature. 2. Inspect the inverter's cooling fan. 3. Examine the internal heat dissipation channels. 4. Ensure the motor and inverter are properly matched. 5. Investigate if the temperature check circuit is faulty.

Cause Analysis:

The ACS800 TEMP fault could stem from any of the following five reasons:

1. High external ambient temperature. 2. Cooling fan malfunction. 3. Blocked heat dissipation channels. 4. Mismatch between inverter and motor. 5. Faulty temperature detection circuit.

We first checked the external ambient temperature. It was around 40 degrees Celsius, which falls within the operational limits of the inverter. The inverter was installed in an electrical room where there were multiple other inverters of the same power rating.

Next, we inspected the inverter’s cooling fan. Once the inverter was running, the fan would start and run without any noise. When removed and tested separately, the fan functioned correctly.

Then, we considered whether the inverter and motor were mismatched. This particular inverter had been running fine for years and had not experienced any overcurrent or overload faults prior to the TEMP fault appearing. Thus, this possibility was ruled out.

We also suspected a potential issue with the temperature detection circuit. Although this remained a possibility, further tests were required to confirm or dismiss it.

Finally, we examined the heat dissipation channel. After fully disassembling the inverter, we discovered that the heat dissipation channel was indeed obstructed. This blockage prevented proper cooling, leading to the fault. This was confirmed as the root cause of the problem.

Repair Process:

After identifying the issue, we began by cleaning the heat dissipation channel. Following this, we reinstalled the circuit boards and capacitor boxes in sequence, ensuring everything met the necessary power-on conditions. Once powered, the inverter showed normal output voltage and balanced load supply at rated current. Although the inverter became warm during operation, it functioned correctly. Therefore, the ACS800 TEMP fault was caused by a blocked heat dissipation channel, ruling out any damage to the temperature detection circuit.

Summary of Experience:

Based on years of experience maintaining ABB inverters, we’ve learned that the majority of faults are often due to clogged heat sinks within the inverter itself. While it’s important to consider all possibilities, focusing on regular maintenance and cleaning can prevent such issues from arising. This case reinforces the need for ongoing attention to these critical components to ensure reliable performance and longevity of the equipment.