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Re: Power factor correction for NST
From: Thomas McGahee[SMTP:tom_mcgahee-at-sigmais-dot-com]
Sent: Thursday, September 11, 1997 11:52 AM
To: Tesla List
Subject: Re: Power factor correction for NST
>
> From: LINEMAN23K-at-aol-dot-com[SMTP:LINEMAN23K-at-aol-dot-com]
> Sent: Thursday, September 11, 1997 12:35 AM
> To: tesla-at-pupman-dot-com
> Subject: Power factor correction for NST
>
> All,
>
> I tried to post on this subject but the mail must have gotten lost
so I will
> try again.
> What size PFC cap should be used on a 15KV-at-60mA NST? Also, how do
you
> calculate this?
>
> It seems to me that at 900VA output there would be 900VA input to
the NST
> (probably more input, assuming losses of the transformer). From my
> calculations, ignoring losses, I come up with 7.5A input and Zpri =
16ohms.
> Using the equation
> C = 1/(2*pi*F*Z) I get 166uF.
>
> This seems like too large a value for the PFC cap. If so, where is
my logic
> flawed? How much of an improvement to the system can I expect with
the PFC
> cap in place?
>
> All comments will be appreciated
>
> Rusty Duncan
>
>
Rusty,
I have seen suggestions ranging from 1 mfd per ma all the way to 3
mfd per ma. Gary Weaver did an experiment some months ago and posted
the results. I am appending a copy of his post. He found that 150 mfd
worked well for 90 ma. This comes out to 1.66 mfd per ma. For the 60
ma transformer you have that comes to 100 mfd. The caps must be rated
for AC use, and I would recommend a 600 VAC value for safety.
Why not get three 50 mfd and then you can try both 100 and 150 mfd?
Hope this helps.
Fr. Tom McGahee
************
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
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