March 31, 20233 yr Greetings, An Axpert MKS 3K-24 UPS installed in a residential unit within a housing complex is showing error(s) 06 (Output voltage is abnormal) and 08 (Bus voltage is too high) supposedly from high AC input voltage. As per the attached photos, >400Vac input voltage is momentarily seen by inverter before the upstream under/over voltage protection relay cuts off the mains supply. What could be the cause of such high input voltage? Lost/broken neutral at the service connection perhaps? NB: The local grid standard is 240/415 Vac and earthing system is TNC-S. No other residential unit is experiencing over voltage.
April 1, 20233 yr 10 hours ago, Kilowatt Power said: What could be the cause of such high input voltage? My guess is it's not actually high voltage; the ADC system of the DSP is kaput and is reading everything too high. Hence the also high bus voltage reading. Can you measure the AC input voltage with a multimeter?
April 1, 20233 yr 2 minutes ago, Coulomb said: My guess is it's not actually high voltage; the ADC system of the DSP is kaput and is reading everything too high. Hence the also high bus voltage reading. Can you measure the AC input voltage with a multimeter? I think the ADC either works or it doesn't. But what is very likely is that the voltage reference is faulty. The Vref could be a separate chip that would be cheap and easy to replace. Sadly, Vref is often internal to the ADC, or DSP chip and then you have a big problem. @Kilowatt Power Any ADC needs a very stable reference voltage to be able to do accurate measurements. It is a special low-noise, temperature compensated low power linear voltage regulator. If the Vref drifts, then the resulting measurements drift.
April 1, 20233 yr Author 3 hours ago, Coulomb said: Can you measure the AC input voltage with a multimeter? A voltage protection relay with voltmeter and ammeter readouts installed before the inverter cuts off the mains supply due to over-voltage. Shall however measure the voltage using a DMM and make a comeback
April 1, 20233 yr Author 11 minutes ago, Kilowatt Power said: A voltage protection relay with voltmeter and ammeter readouts installed before the inverter cuts off the mains supply due to over-voltage. The response time of the under/over voltage protection relay is 1-3s and is set to 170 & 275 Vac respectively. A voltage spike could reach the inverter before it cuts off supply.
May 19, 20233 yr I have exactly the same problem. I also heard a crackling sound that builds up in intensity for a few seconds until it trips.
May 19, 20233 yr 18 minutes ago, Hannes Visagie said: I also heard a crackling sound that builds up in intensity for a few seconds until it trips. Mention of the cracking sounds reminds me of the screws-with-high-voltage-too-close-to-the-case problem. Maybe they haven't fixed the issue in manufacturing after all. It may be worth taking the front coder off, and examining the inside of the front cover for scorch marks. If so, some electrical tape on the back of the case could solve the problem, and avoid a fate like this: From this post.
May 23, 20233 yr Author On 2023/04/01 at 9:27 AM, Coulomb said: My guess is it's not actually high voltage You're right. Nothing to do with high AC input voltage. I've had the inverter examined at the Mecer service centre and they've recommended replacement of the main board.
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