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Constant Voltage Transformer Question

W

Watson A.Name - \Watt Sun, the Dark Remover\

Jan 1, 1970
0
John Woodgate said:
I read in sci.electronics.design that Jim Thompson
4ax.com>) about 'Constant Voltage Transformer Question', on Fri, 31 Dec

There might be 'start-up' issues, if you have a fitting with a lot of
lamps in it, due to inrush current, but AFAIK CVTs work very well with
resistive loads.

Why not regulate all the lighting circuits with one CVT?

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

More like BUZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ.

All the time.
 
W

Watson A.Name - \Watt Sun, the Dark Remover\

Jan 1, 1970
0
Spehro Pefhany said:
On Fri, 31 Dec 2004 13:07:56 -0800, the renowned "Watson A.Name -


Voltage stabilizers are pretty common in third-world countries. I
can't remember where I've seen them for sale though. They look like
the usual metal box with a transformer in it (like 120/240
autotransformers). Not very expensive (China/India etc.). Mohammed has
one here, but he's got little feedback and the item location seems a
bit odd (is it NYC or is it Houston, "Taxes"?).

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=4660&item=3862579
284


Best regards,
Spehro Pefhany
--

One other thing I forgot to mention. In Calif, the electric companies
are obligated to give you service that's within certain limits, I
believe it's 105 to 125VAC. I had a problem with a piece of equipment
that would work fine in one bldg but wouldn't work in another bldg, and
it turned out that the AC was too high a voltage. I talked to the
electricians and they said it was because the transformer was delta
instead of wye. In any case they couldn't change it. Later the lab
moved to another bldg so it didn't make any diff.

But seriously, it's something that you should look into. My guess is
that you're out on the end of a high V line with loads that are dragging
it down, and the electric co decided to boost it to give an acceptable
minimum, instead of fising the problem, a poorly regulated circuit. It
could be that your line needs to have some capacitive buildout, or some
other modification, Too bad you can't mnodel the circuit in SPICE and
figure out what's wrong. ;-)
 
J

James T. White

Jan 1, 1970
0
Jim Thompson said:
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?
 
T

**THE-RFI-EMI-GUY**

Jan 1, 1970
0
Are they blowing up on turn on or is it when the voltage surges? If its
the former, most likely, why not rig up a dimmer circuit with a shunt
relay with a delay-on timer of say 5 seconds. Then everytime the
circuit is turned on, the lamps will soft start for a few seconds giving
the filaments time to warm up a bit.

The RFI-EMI-GUY

Jim said:
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

--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"

The Lost Deep Thoughts By: Jack Handey
Before a mad scientist goes mad, there's probably a time
when he's only partially mad. And this is the time when he's
going to throw his best parties.
 
A

Al

Jan 1, 1970
0
Jim Thompson said:
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

Voltage in my house in Massachusetts is 127 most of the time. I think it
is that high as there are a lot of teardowns being replaced with
MacMansions. These huge houses require a lot of power and it probably
drops considerably just from the pole to the house. My little house just
uses on an average of 350KWH/mo. The biggest drain is the rare use of
the electric oven.

When I got my MacPlus many moons ago, I also bought a TrippLite Power
Regulator/Conditioner. My Plus is still a go although I've heard that
many of them lost their PSs due to surges and sags. I could hear the
relays clicking in the TrippLite my wife would turn on the dryer. Now it
just sits gathering dust.

You want it, you got it, for the price of shipping and handling ;-)

You want specs, I'll send them to you if your're interested.

Al
 
G

Greg Neff

Jan 1, 1970
0
Jim Thompson wrote...

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.

Colour temperature is a problem, especially when mixing lamp types.
We have found that the lamp colour temperature makes a huge difference
in the appearance of wall paint colour, and a mismatch of lighting
makes a room look strange.

In our kitchen we have 4' fluorescent tubes in part of the kitchen,
and a 3-lamp ceiling-mounted fixture in the eating area. We had a
heck of a time finding CFLs with a comparable colour temperature. All
warm-white CFLs are no good. I tried a GE CFL with a 6500K (IIRC)
temperature, but its light output had a very strong and unpleasant
blue component. We ended up using Panasonic "cool white" EFD14E50
lamps (colour temp 5000K). Something with just a touch lower colour
temperature would be ideal.

In our living/dining room and halls we have a mix of incandescent and
"warm white" CFLs. At first we had some Globe Electric CFLs, and the
colour match was excellent. Unfortunately, we had to dispose of them
because of a UL fire hazard warning. We purchased another brand
"Commercial Electric" a.k.a. "Technical Consumer Products", but these
have a noticeably higher colour temperature. So, we will have to try
yet another brand.

If I were GE or Philips or whatever, I would develop and promote
matched pairs. I would market cool white CFLs and fluorescent tubes
with the same colour temperature, and I would market warm white CFLs
and incandescent lamps with the same colour temperature. This would
save me alot of time and money trying to match these on my own.

CFLs with problems:

http://www.ul.com/media/newsrel/nr102604.html
http://www.cpsc.gov/cpscpub/prerel/prhtml05/05064.html
http://www.cpsc.gov/cpscpub/prerel/prhtml05/05005.html

Links:

http://www.ge.com/en/product/home/lighting.htm
http://www2.panasonic.com/webapp/wc...51&catalogId=11005&langId=-1&catGroupId=11288
http://www.globe-electric.com/
http://www.tcpi.com
http://www.sylvania.com/ConsumerProducts/LightingForHome/Products/BulbType/CompactFluorescent
http://www.nam.lighting.philips.com/can/consumer/products_marathon_ES.php

================================

Greg Neff
VP Engineering
*Microsym* Computers Inc.
[email protected]
 
J

Jim Thompson

Jan 1, 1970
0
Are they blowing up on turn on or is it when the voltage surges? If its
the former, most likely, why not rig up a dimmer circuit with a shunt
relay with a delay-on timer of say 5 seconds. Then everytime the
circuit is turned on, the lamps will soft start for a few seconds giving
the filaments time to warm up a bit.

The RFI-EMI-GUY
[snip]

Good point. You're right, they almost always fail at turn-on.

...Jim Thompson
 
B

Bennett Price

Jan 1, 1970
0
Just don't try to use CVT with fluorescent lights; they may not start.
CVT is fine for incandescent.
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that Greg Neff <greg@guesswhichwordgoes
here.com> wrote (in <[email protected]>) about
'Constant Voltage Transformer Question', on Sat, 1 Jan 2005:

All warm-white
CFLs are no good.


I think you probably mean that 'not all are good', rather than 'all are
no good'.
I tried a GE CFL with a 6500K (IIRC) temperature, but
its light output had a very strong and unpleasant blue component.

6500 K is US daylight and is indeed too blue for use in the home. Ideal
for colour-matching and some benchwork.
We
ended up using Panasonic "cool white" EFD14E50 lamps (colour temp
5000K). Something with just a touch lower colour temperature would be
ideal.

5000 K is British daylight, and is beyond reproach. (;-)
In our living/dining room and halls we have a mix of incandescent and
"warm white" CFLs. At first we had some Globe Electric CFLs, and the
colour match was excellent. Unfortunately, we had to dispose of them
because of a UL fire hazard warning. We purchased another brand
"Commercial Electric" a.k.a. "Technical Consumer Products", but these
have a noticeably higher colour temperature. So, we will have to try
yet another brand.

I'm not keen on European 'warm white': it doesn't seem bright enough for
me. I use cool white CFLs and fluorescents wherever possible.
If I were GE or Philips or whatever, I would develop and promote matched
pairs. I would market cool white CFLs and fluorescent tubes with the
same colour temperature,

AIUI, that's what they think they do.
and I would market warm white CFLs and
incandescent lamps with the same colour temperature.

Incandescent lamps (gas-filled) are around 3500 K. I don't think I'd
like a CFL as yellow as that. European warm white is spectrally skewed,
so it's not really possible to assign a colour temperature to it.
 
N

Nicholas O. Lindan

Jan 1, 1970
0
James Meyer said:
Ferroresonant transformers have terrible efficiencies.

Well, yes and no.

They draw the same current from the line at full load and
no load. When used at nameplate rating they are 90% efficient.

At no load most of the current draw is reactive. However, there
are huge core losses in the beasts as they run half the core into
saturation.
If you want to double your power usage, they're great!

With a 50% load that's about what will happen.

If you are in the far north and only need light in the winter
when you also needs lots of heat they'll work just fine.

In Arizona ... probably not a good solution.

OTOH: Very reliable, 1% line regulation on the fancy models,
one of the best protectors against power spikes/surges/nearby
lightning strikes. Cheap on ebay.
 
M

Mark Zenier

Jan 1, 1970
0
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 [email protected] Washington State resident
 
J

JeffM

Jan 1, 1970
0
If you want to double your power usage, [ferroresonants are] great!
With a 50% load that's about what will happen.
If you are in the far north and only need light in the winter
when you also needs lots of heat they'll work just fine.
In Arizona ... probably not a good solution.
Nicholas O. Lindan

Not familiar with deserts?
At night (the only time you should need artificial light),
temperatures drop (summer too).
A tree-hugger would say it's not a good solution for other reasons.
 
J

John Stewart

Jan 1, 1970
0
One other thing I forgot to mention. In Calif, the electric companies
are obligated to give you service that's within certain limits, I
believe it's 105 to 125VAC. I had a problem with a piece of equipment
that would work fine in one bldg but wouldn't work in another bldg, and
it turned out that the AC was too high a voltage. I talked to the
electricians and they said it was because the transformer was delta
instead of wye. In any case they couldn't change it. Later the lab
moved to another bldg so it didn't make any diff.

But seriously, it's something that you should look into. My guess is
that you're out on the end of a high V line with loads that are dragging
it down, and the electric co decided to boost it to give an acceptable
minimum, instead of fising the problem, a poorly regulated circuit. It
could be that your line needs to have some capacitive buildout, or some
other modification, Too bad you can't mnodel the circuit in SPICE and
figure out what's wrong. ;-)

In most systems upstream from the load there is a piece of electrical gear
called a 'line drop compensator'. It simulates the line impedance out to the
load with a set of R's & L's within a subassembly box. Both are adjustable
so that your power company can make allowance for automatic load balancing
over a broad range & a number of different load conditions.

Needless to say that it is not possible to adjust for all the loads but thay
can get pretty close. The error voltage resulting from this gadget controls
automatic switchgear, usually in a 3-phase auto transformer. Sometimes you
will see three separate singlephase transformers on three sucessive poles.

Cheers, John Stewart
 
R

Rich Grise

Jan 1, 1970
0
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 place kinda smelled like hot varnish, however. Luckily they only did
batch about once a week or so.

But it's cool watching a ferroresonant tranny regulate, especially when
you've got a variac and an AC ammeter. As soon as you apply any voltage at
all, the current goes WAY up. The first time I did it, I kinda panicked
when it was drawing 7 amps on the primary at about 3 VAC in. "It's
regulaging!" he said. He was beaming, probably because he designs them.
Of course, the current went to practically zero at no load and full V.

They were also inherently short-circuit protected. Well, current-limited;
I'm not sure if those are really technically different things.

Cheers!
Rich
 
J

John Stewart

Jan 1, 1970
0
One other thing I forgot to mention. In Calif, the electric companies
are obligated to give you service that's within certain limits, I
believe it's 105 to 125VAC. I had a problem with a piece of equipment
that would work fine in one bldg but wouldn't work in another bldg, and
it turned out that the AC was too high a voltage. I talked to the
electricians and they said it was because the transformer was delta
instead of wye. In any case they couldn't change it. Later the lab
moved to another bldg so it didn't make any diff.

But seriously, it's something that you should look into. My guess is
that you're out on the end of a high V line with loads that are dragging
it down, and the electric co decided to boost it to give an acceptable
minimum, instead of fising the problem, a poorly regulated circuit. It
could be that your line needs to have some capacitive buildout, or some
other modification, Too bad you can't mnodel the circuit in SPICE and
figure out what's wrong. ;-)

In most systems upstream from the load there is a piece of electrical gear
called a 'line drop compensator'. It simulates the line impedance out to the

load with a set of R's & L's within a subassembly box. Both are adjustable
so that your power company can make allowance for automatic load balancing
over a broad range & a number of different load conditions.

Needless to say that it is not possible to adjust for all the loads but they

can get pretty close. The error voltage resulting from this gadget controls
automatic switchgear, usually in a 3-phase auto transformer. Sometimes you
will see three separate singlephase autotransformers on three sucessive
poles.

Cheers, John Stewart
 
R

Rich Grise

Jan 1, 1970
0
On 31 Dec 2004 13:22:03 -0800, Winfield Hill

Colour temperature is a problem, especially when mixing lamp types.
We have found that the lamp colour temperature makes a huge difference
in the appearance of wall paint colour, and a mismatch of lighting
makes a room look strange.

In our kitchen we have 4' fluorescent tubes in part of the kitchen,
and a 3-lamp ceiling-mounted fixture in the eating area. We had a
heck of a time finding CFLs with a comparable colour temperature. All
warm-white CFLs are no good. I tried a GE CFL with a 6500K (IIRC)
temperature, but its light output had a very strong and unpleasant
blue component. We ended up using Panasonic "cool white" EFD14E50
lamps (colour temp 5000K). Something with just a touch lower colour
temperature would be ideal.

What about Gro-Lites? Admittedly, they're almost red, but I wonder if
that'd balance out with a cool-white?

Thanks,
Rich
 
W

Watson A.Name - \Watt Sun, the Dark Remover\

Jan 1, 1970
0
[snip]
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]
 
N

Nico Coesel

Jan 1, 1970
0
Jim Thompson said:
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.
 
J

Jim Thompson

Jan 1, 1970
0
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.

I have a two-head work light on a tripod... 2x 500W halogens ;-)

...Jim Thompson
 
R

Richard Crowley

Jan 1, 1970
0
What about Gro-Lites? Admittedly, they're almost red, but I
wonder if that'd balance out with a cool-white?

The lamps made for growing plants don't really care what they
LOOK like, but only that they provide the optimum wavelengths
for photosynthesis (not necessarliy the same wavelengths for
balanced color rendering). I believe some of them make the
green spike even bigger than ordinary floursecent phosphors.

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%.
 

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