It is called "colorvolot", by Sola.

It was sold in the early 1970's--to regulate the line voltage to color tv sets--and make them more stable. It is a Voltage Regulating Transformer--just like the one used in the Zenith flat chassis and chromacolor II sets, along with many mid-1970's color sets of all makes.

It does have a novel feature--it seems to stay "off line-, passing current through it, until an apprecible load is sensed--then the VRT comes into play. It is rated for 3.1 amps--meaning it would work for most vintage color sets--other than some really early ones like the CT-100 and such. Or...maybe even a computer system today. Few of them would draw over 3A.

I SHOULD note--that I do NOT think this is isolated--so it would NOT be ok to use for that purpose...

Got it--just for curiosity..

I've got a saturable reactor line isolation transformer from my summer job this year (they were gonna toss it and offered it to me first :) ). It is a Controlled Power Co. brand unit. It works great, but it is slightly under rated (current wise) for color TV service so I can only run it for a few hours before it gets hotter than I care to let it get...Despite that it does it's job quite well. There are intermittent significant rapid line voltage dips here that are rather annoying when watching a tube set with an unregulated power supply and it eliminates the line dip issue completely.

Yours must be an interesting design to not have isolation and not load the line when unloaded.

I have one that I use all the time with my CTC-7 Abington. You can see it on the floor in the attached photo. It does get hot, and hums quite loudly, but it keeps the voltage at a steady 117 V. These days, I keep it behind the set and the hum isn't very noticeable.

-Clark

I would imagine a saturation transformer would run a little hot normally. Because the
energy required for regulation during a dip would have to be stored by the unit, and the
energy surplus during a surge would have to be dissipated in a non current flow manor,
guess what.... That is heat.... And the energy stored for a dip that also may not have
been used during that cycle would also need to be dissipated, again as heat.

Normal transformers try and be 100% efficient. energy in = energy out.
This one is required to do some regulation.
That is work, and with 'work + energy out = energy in'. If this transformer does all its work
inductively, it will make heat because of the losses in the resistance of the copper.

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Yes, constant voltage transformers (CVTs) run hot by design. It's a very simple circuit, that uses a ferro resonant tank circuit, and intentionally drives the transformer core into saturation. They've been around for many decades and are still being made and used. Here's a link to a commercial site that explains their operation:
http://www.purevoltindia.com/constant-voltage-transformer.html

Even though the ColorVolt has an automatic on/off sensor and relay, I still unplug it when not in use.

What you said makes sense. I always knew they ran hot--compared to a normal tranny--and I knew it was from the saturation--but I did NOT connect the two--till now. Makes sense--that to "boost" the voltage would require some sort of storage and to "buck" it--would require RELEASING that excess energy somehow--as heat. I DO know--that tv sets using them tended to be MORE energy efficient--than those that used series pass regulation were--INCLUDING the Zenith flat chassis.

Not sure why it happeped--but my colorvolt just DIED !!

it was running my Panasonic LCD projo--with an UNDER 200 watt load. Everything seemed fine and THEN--that thermal relay begin to chatter--and the set went off.

At first--I though the transformer had shorted--but that did NOT make sense, since it had NOT smoked or such. But now--it would nOT hold a load--and hummed quite loud and clicked off and on. SO then--i figured the thermal relay had died. This is somehow used to sense when a load is connected and then "shunts" in the ferro tranny. So--I tried to bypass it and the tranny hummed load but NO output. I really felt my tranny had died.

then--I looked at the diagram of this thing--in the Electronics world magazxine from 1970, Feburary. SOMETHING seemed to be dragging down the output. The oil capacitor maybe--YES. For some reason--it is now SHORTED. It is a 5UF 660v cap, from what the diagram in EW says.

NOW_-do I REALLY need a 660 volt cap--I do NOT think the kick voltage from the tranny would get that much over 300 volts--would it--I can get a 5uf 450 or so volt cap easily.

I have one that I use all the time with my CTC-7 Abington. You can see it on the floor in the attached photo. Hey, this all sounds familiar. I remember when you got it!

http://www.antiqueradios.com/forums/viewtopic.php?f=15&t=209410

.

Those types of caps are available from motor shops and HVAC parts places:

http://www.carbonbrush.com/runcapacitorsoval660.htm

http://capacitor.tedss.com/660V

Don't substitute a different capacitance rating! The 5uF is part of a resonant circuit...

It is called "colorvolot", by Sola.


Two things to watch out for on saturable reactor power transformers.

1. They don't generate a sine wave, therefore most AC volt meters will not give an accurate RMS reading. As the waveshape changes with the voltage adjustment, so most meters will show a change when they are actually holding RMS voltage constant. I used two 10 amp Sola transformers to stabilize high amperage lighting for critical photographic work back in the 60's and 70's.

2. Don't put magnetic recordings anywhere close to them as the rather strong magnetic fields they emit will erase them. This little booboo forced me to buy a new operating system for friend's computer that I was testing. Turning off a Sola can magnetize ferrous object near them, which might not be too good for a color TV.

James.

Hey, this all sounds familiar. I remember when you got it!

http://www.antiqueradios.com/forums/viewtopic.php?f=15&t=209410

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Hey Jim! I had forgotten about our PM exchange when I was buying this from the ARF classifieds. I'm surprised the photos and everything are still there.

Earlyfilm: That's two excellent pieces of information. That explains why I got much more stable meter readings with an analog VTVM than with my DMM. And I think I'd better move some of my VHS tapes further away!