Re: How much distortion is acceptable on residential utility power?

On Thu, 19 Mar 2009 06:59:50 -0700 (PDT), MooseFET
<kensmith@xxxxxxxxx> wrote:

On Mar 19, 1:28 am, "JosephKK"<quiettechb...@xxxxxxxxx> wrote:
On Mon, 16 Mar 2009 20:12:53 -0700 (PDT), MooseFET



<kensm...@xxxxxxxxx> wrote:
On Mar 16, 7:48 pm, Eeyore <rabbitsfriendsandrelati...@xxxxxxxxxxx>
wrote:
MooseFET wrote:
On Mar 15, 5:33 pm, Sylvia Else <syl...@xxxxxxxxxxxxxxxxxxx> wrote:
MooseFET wrote:

The power company tries to supply a near perfect sine wave.  The
generators tend to make very good sine waves.  The impedance of the
local part of the power network and the nearby nonlinear loads are
going to be the main source of the distortion.

And expect to see it get worse as people replace incandescent lamps with
  compact fluoros.

I expect that the mains power will improve over the next many years.
A lot of equipment draws its current in thin spikes at the peaks.
Modern designs do this less so.

The CFLs will tend to draw current over a wide part of the cycle.  The
capacitor after the rectifier is small enough that the the ripple is
very large.

Poor man's way of improving harmonic currents !

Cutting production cost, allowing cheaper rectifiers and fitting into
smaller space also come from that one design choice.  Th funny thing
is that brand to brand, there seems to be a large variation.  I've
seen 2uF and 10uF.

Does it vary by lamp power?

I think they were all about the same power. I didn't check the power
ratings I just took a few that I had on hand and took a hammer and
vicegrips to them.

I doubt that there was a 5:1 power range.

Oh. OK. I was interested in finding out what else might have varied
in sync with capacitor size.
.
.

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