Gavin makes a good point in that it might have been an abnormal 11/22kV switching scenario which has resulted in a lower fault level locally. For this period, voltage fluctuations on the network might have been greater than usual when motors were started etc. Is there a sewage or water pumping station near? A factory? As Gavin pointed out, the voltage only has to drop below the threshold of the UPS before the UPS will kick in. And this may not have been noticeable in your household lights. My original reply was more discounting the idea that the signals power companies use to switch streetlights, hot water cylinders, tariff meters etc were affecting your UPS. These are typically in the order of 2-6% (200-400Hz, older systems 1500Hz) and generally not noticed. Happy to be proved wrong. If your UPS checks out fine and the batteries are okay, then your UPS was doing its job. The power networks aren't perfect and do need maintenance from time to time so it warrants protecting your computers etc. On Monday 03 October 2005 09:07, Gavin Denby wrote:
As a tech using a lot of mains sensitive equipment with about 25 years of suffering the bad power in NZ I would suggest that if the ups is fine today you have 2 options
1. Brown out - Very good chance on this, the average UPS switches fast to avoid letting the power fall to low, so if the NZ supply, usually 240V falls to say 200-210 ( supply company doing line maintenance and running on a temp (not very stable ) supply arrangement) your lights will be fine, most equipment will work fine ( but you toaster will take longer to make toast) and the ups will try to switch to battery. if you are right on the ups switching threshold ..... lots of clicking.
2. the ups batteries could be suspect. I assume you test them occasionally ?? Its amazing how many problems a tired cell in a battery causes a ups.
On the aside, I looked at our data from last night and we didn't see anything north of Hamilton. so its at most a local thing.
daylight saving was 2am, so it shouldn't be involved, I go for early morning hot wire line maintenance as a rough guess. WEL seem to like to do a lot at night nowadays
On 3/10/2005, at 8:55 AM, Chris O'Halloran wrote:
Hello,
As an electrical engineer with 10 years experience working in electricity distribution systems, I doubt very much it would have anything to do with the lines company signalling system
Unless you can record a power quality or disturbance issue, I would suspect the problem is with the UPS.
Good luck,
On Sunday 02 October 2005 23:01, Kyle Carter wrote:
Just an inquisitive question. My UPS seemed to go mental last night/this morning (around midnight Sat Oct 1st) flicking between battery and mains repeatedly for a few hours.. But no flickering lights or anything..
Im wondering if anyone else had something similar? Im assuming it may have been the power company doing something weird re: daylight savings?
Kyle Carter
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