magnetic field

[Winfield Hill]

Jim Thompson wrote...

I was wondering how Constant Voltage Transformers would perform with
lamp loads. I'm thinking of room-by-room regulation for ceiling
fixtures... since, 15' up, it's tricky with a lamp changer pole :-(

Why not change to electronic mini-fluorescent lamps? I'd imagine
they aren't very voltage sensitive and now they're available with
decent color-temperature phosphors, and some can work with dimmers.
Save on electricity, cooling energy, and manpower.


--
Thanks,
- Win

 

[artie]

Been a while since I dealt with these beasties, and I'm operating under
the influence of OTC cold medication, but I seem to remember the
constant-voltage devices were saturated-core, and ran hot and noisy.
Had a 6800 development system (Jupiter II, all wire-wrapped) which used
a ferroresonant transformer. Hot and noisy! And if I leaned back in
my chair while using the phone, the headset got close to the thing,
inducing all sorts of fun into the conversation!


In article <phebt0t0702depn17p2vc4nt0c3kip57lg@4ax.com>, Jim Thompson
<thegreatone@example.com> wrote:

A major pain-in-the-ass in Arizona is lightbulb lifetime, particularly
this time of year, where one day will require heat and the next not.

So the AC voltage regulation sucks... often popping up to 130VRMS.

I was wondering how Constant Voltage Transformers would perform with
lamp loads.

I'm thinking of room-by-room regulation for ceiling fixtures... since,
15' up, it's tricky with a lamp changer pole :-(

I have easy attic access, pull-down-stair ladders, and the attic is
tall enough that I can stand upright to work in most locations.

...Jim Thompson

--
Namaste--

 

[James Meyer]

On Fri, 31 Dec 2004 14:56:31 -0800, artie <artie.m@gmail.com> wroth:

Been a while since I dealt with these beasties, and I'm operating under
the influence of OTC cold medication, but I seem to remember the
constant-voltage devices were saturated-core, and ran hot and noisy.
Had a 6800 development system (Jupiter II, all wire-wrapped) which used
a ferroresonant transformer. Hot and noisy!

Ferroresonant transformers have terrible efficiencies. If you want to
double your power usage, they're great! Although Jim T's description of his
house seems to indicate that power usage is the least of his worries.

Jim

 

[The Phantom]

On Fri, 31 Dec 2004 13:50:22 -0700, Jim Thompson <thegreatone@example.com> wrote:

A major pain-in-the-ass in Arizona is lightbulb lifetime, particularly
this time of year, where one day will require heat and the next not.

So the AC voltage regulation sucks... often popping up to 130VRMS.

Here in the Pacific Northwest, high line voltage is the norm (130V is quite common).
Home Depot and others sell incandescents rated at 130V. Since the life of incandescents
varies as the inverse of the 12th power of the applied voltage, switching from 120V bulbs
to 130V bulbs makes quite a difference.

I was wondering how Constant Voltage Transformers would perform with
lamp loads.

I'm thinking of room-by-room regulation for ceiling fixtures... since,
15' up, it's tricky with a lamp changer pole :-(

I have easy attic access, pull-down-stair ladders, and the attic is
tall enough that I can stand upright to work in most locations.

...Jim Thompson

 

[James T. White]

"Jim Thompson" <thegreatone@example.com> wrote in message
news:eohbt0lu1lkiue8t9po6dfe07p7h8kjn8f@4ax.com...

Probably too much for one transformer... I have 500W just in the
kitchen; but I'm open to suggestions... all the ceiling lighting is
off of a single sub-panel.

I've used 3KVA Sola CVTs and I believe they made 5 KVAs. Just how big is your

load?

 

[Watson A.Name - \"Watt Su]

"Rich Grise" <richgrise@example.net> wrote in message
newsan.2005.01.01.21.14.16.112132@example.net...

[snip]

You do know that they are liable to hum, don't you?

More like BUZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ.

All the time.

I worked for a battery charger guy once. He made ferro trannies for
everything, and he potted them. Actually, dipped them in hot varnish,
then
baked them out for a day.

They were absolutely silent.

The ones we have are true Solas, and the transformer itself is not so
much the reason it buzzes. The whole chassis vibrates, probably because
it has to be made out of steel, because the beast weighs close to a
hundred pounds (45kg).

[snip]

Cheers!
Rich

 

[Kim Sleep]

Boy...is this one a few years late....


<reporters@NewYorkTimes.com> wrote in message
news:F2DBd.656289$Pl.358588@pd7tw1no...

As reported by the New York Times, Bill clinton was caught by
photographers over the New Year in a lewd sex act with a prostitute.
Included here are the just released photos confirming it is not only
Monica Lewinsky that shines the brass knobs.

--------------------------------------------------------------------------------

 

[Nico Coesel]

Jim Thompson <thegreatone@example.com> wrote:

On 31 Dec 2004 13:22:03 -0800, Winfield Hill
hill_a@t_rowland-dotties-harvard-dot.s-edu> wrote:

Jim Thompson wrote...

I was wondering how Constant Voltage Transformers would perform with
lamp loads. I'm thinking of room-by-room regulation for ceiling
fixtures... since, 15' up, it's tricky with a lamp changer pole :-(

Why not change to electronic mini-fluorescent lamps? I'd imagine
they aren't very voltage sensitive and now they're available with
decent color-temperature phosphors, and some can work with dimmers.
Save on electricity, cooling energy, and manpower.

Do they make those with floodlight shaping?

Yes, but they probably won't fit in the current sockets. I have 2
floodlight shaped lamps which I use to as a light during construction
work. Each of them equals to a 150W bulb.

--
Reply to nico@nctdevpuntnl (punt=.)
Bedrijven en winkels vindt U op www.adresboekje.nl

 

[Richard Crowley]

I was taught that one of the corrolaries of Murphy's Law is...
"Amplifiers will oscillate. Oscillators won't."

 

[Clarence_A]

"Ken Smith" <kensmith@green.rahul.net> wrote in message
news:cr7973$b6l$3@blue.rahul.net...

As usual "Ken Smith" had nothing intelligent to say!

 

[Rich Grise]

On Sat, 01 Jan 2005 00:04:06 -0800, Watson A.Name - "Watt Sun, the Dark
Remover" wrote:

I built up a FET version of the phase shift oscillator on the right of
http://ourworld.compuserve.com/homepages/Bill_Bowden/page8.htm#func.gif

Do you mean this one?

http://ourworld.compuserve.com/homepages/Bill_Bowden/page8.htm#phase.gif

you link puts me at "Triangle and Squarewave Generator".

If you mean the "Low Frequency Sinewave Generators",

I used a 1.5k source resistor bypassed by a 1000 uF cap.

Well, that'll kinda degenerate your source follower output.

The drain load
resistor is 3.9k, and the supply voltage is 9VDC.

This confuses me, because the circuit I see has no drain load resistor,
it's merely a source follower buffer. The 2N3906 is the gain element.

Or are you talking about a completely different circuit?

Thanks,
Rich

 

[Ken Smith]

In article <UTGBd.5179$wZ2.1876@newssvr13.news.prodigy.com>,
Clarence_A <no@No.com> wrote:

"Ken Smith" <kensmith@green.rahul.net> wrote in message
news:cr7973$b6l$3@blue.rahul.net...

As usual "Ken Smith" had nothing intelligent to say!

As usual Clarence_A deletes all the quoted text just to put in a worthless
comment> One wonders why he bothered to comment since he had nothong
useful to add.

--
--
kensmith@rahul.net forging knowledge

 

[Watson A.Name - \"Watt Su]

"Richard Crowley" <rcrowley7@xprt.net> wrote in message
news:10teddib94tekc2@corp.supernews.com...

I was taught that one of the corrolaries of Murphy's Law is...
"Amplifiers will oscillate. Oscillators won't."

Well, it almost oscillates. Like for a minute or so. But the period of
a cycle was 17 seconds - too long.

So I removed the three 10 uFs and put 2.2 uFs in their place. Now it's
faster, but it's back to damped oscillations that settle down in 20 or
30 seconds. Back to work..

 

[John Woodgate]

I read in sci.electronics.design that Richard Crowley
<rcrowley7@xprt.net> wrote (in <10tedrasvkl8406@corp.supernews.com&gt
about 'Constant Voltage Transformer Question', on Sat, 1 Jan 2005:

Note that film/video people are moving more and more towards
flourescent lighting and there are several vendors now selling
tubes (both traditional and CFL) at color temps of 3000K, 3200K,
5600K, etc. etc. to match industry-standard incandescent sources.
And many of these lamps have color-rendering index (CRI) > 90%.

I don't see how you can have a CRI of 90% with a CT of 3000 K.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

 

[Rheilly Phoull]

"Clarence_A" <no@No.com> wrote in message
news:VKNBd.6071$yV1.5996@newssvr14.news.prodigy.com...

"Ken Smith" wrote
Clarence_A wrote:
[...]
When "Ken Smith" Has NOTHING to say, there is nothing to
quote!
Ah but you see I did have something to say and that was:
snip
--
kensmith@rahul.net forging knowledge
---------------------^^^^^^^^^^^^^^^^^^

Again "Ken Smith" dribbled with only a poor political opine, and
nothing of value to say!


Why dont you pair of kids just FOAD and make everyone else happy ??

--
Regards ..... Rheilly Phoull

 

[Mark Zenier]

In article <phebt0t0702depn17p2vc4nt0c3kip57lg@4ax.com>,
Jim Thompson <thegreatone@example.com> wrote:

A major pain-in-the-ass in Arizona is lightbulb lifetime, particularly
this time of year, where one day will require heat and the next not.

So the AC voltage regulation sucks... often popping up to 130VRMS.

I was wondering how Constant Voltage Transformers would perform with
lamp loads.

I'm thinking of room-by-room regulation for ceiling fixtures... since,
15' up, it's tricky with a lamp changer pole :-(

I have easy attic access, pull-down-stair ladders, and the attic is
tall enough that I can stand upright to work in most locations.

Look in the Newark or Allied catalogs/web sites for Line Conditioners
or Power Conditioners. These are automatic switched tap transformers.
Or for more entertainment value, they may still make servo driven
variacs. Staco. SL Waber, Tripplite, Stabiline, ...

Mark Zenier mzenier@eskimo.com Washington State resident

 

[Jamie]

Watson A.Name - "Watt Sun, the Dark Remover" wrote:

"Richard Crowley" <rcrowley7@xprt.net> wrote in message
news:10teddib94tekc2@corp.supernews.com...

I was taught that one of the corrolaries of Murphy's Law is...
"Amplifiers will oscillate. Oscillators won't."


Well, it almost oscillates. Like for a minute or so. But the period of
a cycle was 17 seconds - too long.

So I removed the three 10 uFs and put 2.2 uFs in their place. Now it's
faster, but it's back to damped oscillations that settle down in 20 or
30 seconds. Back to work..


Second note. you may want to try a R to ground at the

gate, this will help match the phasing angle and mite
be your problem.

 

[John Larkin]

On Sun, 02 Jan 2005 15:39:48 -0500, John Popelish <jpopelish@rica.net>
wrote:

You can get a bit less loss out of the phase shift network if you
stage the impedances. Say, 2.2 uf and 150k for the left one, 1uf and
300k for the second one and .47 uf 680k for the right one.

Cool. In the limiting case where each RC doesn't load the one before,
three RCs give 180 degrees shift with a gain of 0.125.

If you did 4 RCs like this, 45 degrees each, gain is 0.25!

Etcetera, I think.

John

 

[Paul Rubin]

nooneinparticular314159@yahoo.com writes:

What can I get to replace this that will solve this problem?

http://www.turnoffyourtv.com/

 

[Jim Waggener]

<nooneinparticular314159@yahoo.com> wrote in message
news:1104719289.791502.171590@f14g2000cwb.googlegroups.com...

Until a few weeks ago, I had line of sight to several local TV
transmitters. Then someone put up a large building in between me and
the transmitters. Suddenly, my VHS reception has gone from excellent
to poor or terrible. I can't find a good antenna position where I
don't get lots of interference. Cable in my area is way too expensive,
so I don't consider it to be a good solution. I am currently using a
Radio Shack amplified antenna with two telescoping antennae, a VHF/UHF
switch, what appears to be a loop antenna that can be placed in a
vertical or horizontal position, and a rotating knob that changes the
fine tuning. What can I get to replace this that will solve this
problem?

Thanks!

DishNetwork or DirectTV They both beat cable hands down.