Adding in the harmonics makes sense for power factor.
Not in the traditional way but in the same way that Sine wave current and
Cosine wave voltage produces zero Watts.
Orthogonal functions, when multiplied and integrated over a full cycle
produce a result of Zero (definition of orthogonal functions).
Harmonics are orthogonal to the fundamental frequency. So, the 60 Hz
fundamental frequency Voltage and
the harmonics of 60 Hz current produce no power but do produce VoltAmps
which is the RMS value of the
Voltage times the RMS value of the Current. A Fourier Series is a set of
orthogonal functions. All the elements of
a Fourier Series are Orthogonal to each other.
73
Bill wa4lav
At 03:39 PM 3/8/2013 -0800, Jim Brown wrote:
On 3/7/2013 6:26 PM, KA4INM wrote:
So you are saying our tube HPA's hV power supplies have a near unity
power factor?
Thinking about your question and my reply, it occurred to me that you
might not be aware of how Power Factor has been redefined to include both
Phase Angle (the original definition) AND harmonic current.
The original phase angle contribution is now called the "Displacement
Power Factor" and is the cosine of the angle between fundamental (50/60
Hz) current and voltage, the Harmonic contribution is called the"
Distortion Power Factor," and the the ratio of the fundamental power to
the total RMS power, and the "Total Power Factor" is the Displacement
Power Factor multiplied by the Distortion Power Factor.
In the "olden days," when loads were mostly light bulbs (resistive),
heaters (resistors), and motors, load current tended to be a bit
inductive, so power factor correction meant adding parallel capacitance.
Now, loads are heating (resistors, but pulsed to make them variable),
electronic power supplies, inductive motors, and motors with variable
speed controllers (which draw mains current as switching power supplies).
Now, power factor correction is more likely to involve the reduction of
harmonic current.
As I understand conditions in the EU (thanks to my activity in
international standards work), equipment made and sold there tends to be
compliant with EU regulations. EU EMC regulations do place limits on
Power Factor, RF Emissions, and mains Leakage Current, and they require
that Susceptibility to RFI be stated on the product label or data
sheet. So -- since SPE amps are made in Italy, an EU country, there's a
good chance that they are compliant with EU regulations. Or maybe not. :)
73, Jim K9YC
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