[plug] Power supply replacement on a Saturday morning

[Craig Foster]

Bill Kenworthy wrote:
> Power in Perth is nominally on the high side at 240vac: means close to
> the transformers can be a lot higher, and cheap powersupplies have not
> been designed with enough margin.  Above ground powerlines dont help
> when storms are around. Also long, hot summers ...
> 
> It all takes a toll over time!
> 
Western Power have copped so much flack on this that _most_ middle to
inner suburbs are on average pretty normal. Outer suburbs are still a
power no-mans land.

What is more damaging is the power consumption spike at 6pm every day.
The UPS here (Nollamara) has some interesting graphs to show. Power
seems to hover at 245-249V throughout the middle of the day and dip, as
low as 224V, at 6pm. We use gas, so there's no additional current usage
in our house at 6pm. This doesn't rule out our immediate neighbours
influencing this.

Commonsense suggests that WP "copes" with load, not by ramping up to
voltage at certain times, but by setting the unloaded voltage higher
(hence the 250V discussions).

It doesn't help that so many electrical devices are rated not at 240V
but 230V. Or are rated 100V (_below_ the US 110V std) to 240V (The
Australian/UK standard but with no margin). Plug packs are notorious for
being underspecced. 

CraigF.

PS sysmon[5].png is daily, sysmon[1].png is weekly UPS stats.
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