Good point of clarification here Jim!
Leigh
VK5KLT
-----Original Message-----
From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of Jim Brown
Sent: Friday, 8 March 2013 11:30 AM
To: amps@contesting.com
Subject: Re: [Amps] FW: Power factor correction on tube amps
On 3/7/2013 3:49 PM, KA4INM wrote:
> No, the transformer is all inductive and the diodes conduct for most
> of the sine wave, but not all, at that transition the current changes
> abruptly causing distortion.
NO! Only the "imperfections" in a transformer are inductive (and
capacitive, and resistive). The relatively inductance that we see in the
circuit is "leakage inductance" -- and is due to the relatively small
part of the flux from one winding that does not couple to the other. For
any decent transformer, it's a very small fraction of the inductance of
a winding.
The equivalent circuit of a transformer is complex -- in addition to the
leakage inductance, there's resistance in the wire, resistance coupled
from the core, capacitance between turns, capacitance between windings.
At power frequencies though, we don't see the inductance or capacitance,
only the resistance. And if we look into one winding, we see the load
impedance on the other winding multiplied by the square of turns ratio.
73, Jim K9YC
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