[Amps] FW: Power factor correction on tube amps

[Jim Brown]

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