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Re: [Amps] FW: Power factor correction on tube amps

To: amps@contesting.com
Subject: Re: [Amps] FW: Power factor correction on tube amps
From: Jim Brown <jim@audiosystemsgroup.com>
Reply-to: jim@audiosystemsgroup.com
Date: Fri, 08 Mar 2013 15:39:15 -0800
List-post: <amps@contesting.com">mailto:amps@contesting.com>
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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