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Re: Power Factor Correction weirdness?
Yes this is right...
By shorting the output, you have put a fairly small load (just the IR and
iron losses in the transformer) on the line (it would be like just hooking
an inductor across the power line). With no PFC, the current can be quite
high, but because there isn't any actual load, it is out of phase with the
voltage (i.e. the PF is low).. Stated another way, the VoltAmps is high but
the Watts is low.
As you add capacitors, the VoltAmps (which is really what you are measuring)
starts to get smaller, and at some point it will equal the Watts (i.e. when
PF=1).. if you keep adding caps, the current will start to rise, as the
power factor goes the other side (capacitive instead of inductive) of 1.
-----Original Message-----
From: Tesla List <tesla-at-pupman-dot-com>
To: tesla-at-pupman-dot-com <tesla-at-pupman-dot-com>
Date: Wednesday, February 09, 2000 1:43 PM
Subject: Power Factor Correction weirdness?
>Original Poster: Adam <adamsmith-at-mediaone-dot-net>
>
>
>Can someone explain what I'm seeing when I attempt to power factor correct
>my neons? I've got my DMM in series with the primary of a 12,000 60mA NST,
>and the secondary of the NST is shorted. With no PFC caps, it reads 7.13
>Amps. But when I start adding caps in parallel with the NST primary, the
>current reading drops dramatically-- more than I expected it to. Here are
>the results:
>
> PFC Caps Ammeter Reading (amps)
>
> 0 7.13
> 50 uF 4.96
> 100 uF 2.81
> 150 uF 1.14
>
>What's going on here? is this right?
>
>-Adam
>adamsmith-at-mediaone-dot-net
>
>
>