Archive for November, 2007

My AC Input Voltage

Back in the summer I finally got tired of a number of my UPS backed machines being unexpectedly (although properly, via automation) shutdown. Since the automated shutdowns weren’t due to a power outage (I probably would have noticed the power going out; actually I do notice the power going out, those shutdowns weren’t unexpected) I figured it was due to prolonged instances of under voltage — Penetanguishene used to be notorious for prolonged periods of under voltage; so much so that, during the late 80s and early 90s, we used to literally blow up the transformers on the utility poles in front of my father’s plastics factory due to too high current draw during the too low voltage periods.

Now it turns out that in every instance, since the summer, that I’ve noticed an abnormal voltage situation it has been a case of over voltage. In one case this summer there was an over voltage of 25+ volts (20%+) with a reading of 145 VAC, on a 120 VAC nominal circuit, for more than 5 minutes. Instances of 15% overages have been seen for more than 15 minutes at a time. It’s no wonder why I have to replace so many destroyed electronics every year.

So, since I graph nearly everything that changes state, I started graphing the AC input voltage of a small APC UPS at work. The resolution is only 1 VAC, but so far, there hasn’t been an instance of over voltage since I started graphing the input voltage. Which is great since I’m not graphing it to pinpoint the cause so that I can fix the problem; there’s nothing I can do to fix the problem, aside from complain to Barrie Hydro, which I do regularly anyway.

AC Input Voltage

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