BEHOLD! The ratio transformer!

[CaptnYellowShirt]

I've been looking at buying a ratio transformer for a while. I found this one on eBay earlier this morning and found the photo to be kind of funny:

http://r.ebay.com/wwJ3fv

The rest of this post is just what popped into my mind after seeing it:

And Tesla said, "The LORD delivered unto me six knobs of voltage division designed with the finger of God; and on them was written according to all the numbers, which the LORD spake with you in the mount out of the midst of the fire in the day of the assembly."

After the full forty days, Tesla and Westinghouse came down from the mountain with the knobs of voltage: "And it came to pass, as soon as he came nigh unto the camp, that he saw the Kelvin, and the Varley: and Tesla' anger waxed hot, and he cast the knobs out of his hands, and brake them beneath the mount."

[TerraHertz]

Hah, yeah, amusing pic.

I didn't know such a thing existed. Darn, now I want one.

Ebay browsing from that one led to ebay # 400653434352

3-Phase Power and Filament Transformer, 1+1 pcs. Pri: 3x380-400VAC. One type for power and the other for filament power.
With different voltage Inlets / Outlets.
The Ultimate Power Source for High End Amps. You can use 3-phase balanced filters after which give an optimal clean power. Forget better cables and other magical things. Here is the source for real good sound = Good power to amplifie. (Shit in-Shit out)....
Heavy transformers, 8 kg each.

Because who needs voltage regulators when you can use giant lumps of iron and filters. 

[PedroDaGr8]

These come up from time to time on here. They are much better than a resistor divider (though for AC only, no DC) because they are based on a physical constant (number of turns) there is functionally zero drift and they can be made VERY precise.

[lowimpedance]

And when 'GOD' had finished practicing he created the DT72a 7 decade divider, or actually it was ESi come to think of it!.

Gertsch made some nice stuff as did ESi. Of course cal labs also make there own too  .

[PedroDaGr8]

And when 'GOD' had finished practicing he created the DT72a 7 decade divider, or actually it was ESi come to think of it!.

Gertsch made some nice stuff as did ESi. Of course cal labs also make there own too  .

Didn't Gertsch make it then ESI bought out Gertsch. Then ESI was I think purchased by IET Labs.

[mrkev]

We had something "like that" in high school. It was three phase autotransformer for 380V and about 10kW, it had big wheel which moved the carbonic collectors across the coils, was about 2m high and more than 1m in diameter... We used it to power motors... You could tell when it was swiched on (with load), even tho school had transformer from 22kV power line directly underneath it...

[lowimpedance]

We had something "like that" in high school. It was three phase autotransformer for 380V and about 10kW,

HUH ......... not quite the same 

And when 'GOD' had finished practicing he created the DT72a 7 decade divider, or actually it was ESi come to think of it!.

Gertsch made some nice stuff as did ESi. Of course cal labs also make there own too  .

Didn't Gertsch make it then ESI bought out Gertsch. Then ESI was I think purchased by IET Labs.

I dont believe they were related at that time, but maybe IET has aquired them since

[CaptnYellowShirt]

Gertsch made some nice stuff as did ESi. Of course cal labs also make there own too  .

The book Coaxial AC Bridges is the seminal work on the subject.  A good read for anyone that wants to make AC measurements to within 10^-9 parts.