[wellylug] ups

[nic]

If I remember rightly, ripple control is a 1kHz sine wave signal imposed on the mains with 
an amplitude of around 20 V RMS. To filter it out you'd need some biiig inductors/mains 
caps. And be confident playing with mains. It's probably easier to get a better UPS.

Nic

Jim Cheetham wrote:
> On Sun, Mar 30, 2008 at 10:25 PM, David Antliff <david.antliff at gmail.com> wrote:
>>  I have a strange observation - every hour, on the hour, both UPSes go
>>  into a semi-random switching state where they switch on and off mains
>>  power every few seconds for about a minute. The APC one has a
>>  'sensitivity control' so I made it less sensitive and it stopped doing
>>  it. The Dynamix one doesn't seem to have this control so I have to put
>>  up with lots of audible switching clicks every hour. Quite annoying. I
>>  believe it's the ripple control causing this and I'd love to know if I
>>  can legally block this somehow... (I have gas hot water). Maybe some
>>  sort of filter on the UPS AC input?
> 
> The ripple control was responsible for causing similar shut down
> problems on a windfarm recently built near Queenstown (don't remember
> the name, sorry), and they just built a couple of filter blocks to
> take it out :-)
> 
> Given that the ripple signal is imposed for commercial reasons (i.e.
> to allow load management by the power company) and that the power
> companies know who is on a load managed contract, blocking it from a
> non-load-managed location should be just fine.
> 
> A quick google didn't reveal any precise info on how to filter the
> ripple out (I'll guess it's not trivially the same as an output
> smoothing filter from a transformer), but it is possible and I can't
> see any legal objection, unless your electricity supply is contracted
> on the expectation that you will be receiving the ripple ... :-)
> 
> -jim
> 
>