In article ,
"Uncle Peter" writes:
On Sat, 19 Apr 2014 09:24:40 +0100, Andrew Gabriel wrote:

In article ,
John Rumm writes:
On 19/04/2014 01:09, Uncle Peter wrote:
On Sat, 19 Apr 2014 00:43:30 +0100, John Rumm
wrote:

On 18/04/2014 11:01, Uncle Peter wrote:
On Fri, 18 Apr 2014 10:44:39 +0100, Andrew Gabriel
wrote:




And I guess there's no way to cancel a harmonic like you can shift
normal PF with a capacitor.

Its not easy once the harmonic content has been created. The PFC built
into modern SMPSUs will suppress the creation of it by spreading the
duration of the current draw by the PSU - rather than just concentrating
it at the peak of the voltage waveform.

These are modern SMPSUs, just very cheap ones (about half the price).

Anything over 75W is required to have PFC these days...

and for electronic ballasts for lighting, anything over 25W, including
CFLs with integral ballasts.

Required isn't the same as has.

I only have one CFL over 25W (a 30W one from Homebase many years
ago - they don't do them anymore), and it does have a PF of almost 1.
This is probably also partly why most consumer CFL retrofit ranges
stop below 25W.

As for separate electronic ballasts, they've all been PF 0.9 for
probably a decade or more. Once the design and initial roll-out is
done, there is next to no additional cost anymore. These products
are extremely high margin anyway - the component costs are tiny
compared with the selling price.

--
Andrew Gabriel
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