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Re: PFC caps on neons
Subject:
Re: PFC caps on neons
Date:
Wed, 2 Apr 1997 07:35:45 +0000
From:
"John H. Couture" <couturejh-at-worldnet.att-dot-net>
To:
Tesla List <tesla-at-pupman-dot-com>
At 05:51 PM 3/31/97 +0000, you wrote:
>Subject:
> PFC caps on neons
> Date:
> Mon, 31 Mar 1997 11:07:49 -0800
> From:
> Gary Weaver <gweaver-at-earthlink-dot-net>
> To:
> tesla-at-pupman-dot-com
>
>
>Power Factor Correction capacitors connected to the primary of a neon
>transformer reduces the input amps by 40%. I have
>3 neons connected in parallel. They are 12K 30 ma each on my Tesla
>Coil. I connected an amp meter to the primary of the
>neons and it reads 11.5 amps. Then I connected one 40 uf capacitor in
>parallel with the primary and the amp meter reads 10
>amps. Then I connected another 35 uf cap in parallel with the 40 uf and
>the amp meter reads 9 amps. I connected another 35
>uf cap and the amps dropped to 8 amps. Another 40 uf cap made the amps
>drop to 7 amps. I added another 40 uf and the
>amps went up to 7.5 amps. It looks like 150 uf for 3 neons in parallel
>works the best. The PFC capacitors have no affect on
>the TC secondary coil spark output. The rating for 3 neons is 12K 90 ma
>= 1080 watts. The input without PFC caps is 11.5
>amps X 120 volts = 1380 watts. The input with PFC caps is 7 amps X 120
>volts = 840 watts. How can I have 840 watts IN
>with PFC and 1080 watts OUT? The meter must not be giving me a true
>reading.
>
>I connected the 3 neons to my watthour meter. With out the PFC
>capacitors the dial turns from 0 to 40 in 10 seconds. With
>the PFC capacitors the dial turns from 0 to 30 in 10 seconds. This
>shows a decrease in power of 25% using PFC capacitors.
>
>Gary Weaver Experement # 7946
>
>------------------------------------------------
Gary -
Watts = Volts x amps x power factor
Standard wattmeters read correctly only with RMS sine waves and have
limited frequency range.
Tesla coils are not RMS sine wave loads because the currents taken from
the
utility are in surges and are of varying waveshape.
The best way to make load comparisons of Tesla coils is with
incandescent
lamps and a light meter as shown in the Tesla Coil Construction Guide.
With
proper calibration this will give you effective amps and multiplied by
volts
will give you watts. A hot wire ammeter can be used if you can find one.
The advantage of using the lamp is because it is little affected by
changes
in frequency and waveshape. All standard meters that use magnetic fields
for
the force required to move the indicator will give incorrect readings
when
used with Tesla coils. This is the reason that making tests of Tesla
coils
using standard meters is of little value.
Note that the 1080 watts of your neon transformers are a ficticious
rating
when used with Tesla coils. During Tesla coil operation using neons the
true
wattage
can be much lower than the nameplate rating.
Because Tesla coils are run for only short periods of time there is no
advantage to using power correction capacitors to reduce the load.
John Couture