A Bit of Help Needed from the Elders

I've only ever seen one of these and it was a "BEAST" for a coal mine, but only three phase.

The reason I'm putting this up is that one of the impressive things about it was the necessary isolation from people and living things. It was encased in a housing of lead bricks due to "radiation" issues that I'm sure you will understand.

From memory it was 1100Amp capability to supply mining and winding equipment at the mine.

Over 30 years ago and I have no idea what teh circuitry was.

This is the type I used to work with, British Thompson Huston 500A 220V. They've had me fascinated ever since.

That thing looks a little bit like a three phase fluorescent lamp I once made. But I didn't draw off any DC power.

on the web I found many like this.

http://tinyurl.com/8bj855t

http://www.vintage-radio.net/forum/showthread.php?t=53442

Re: A rather nice German website

Hi Gents, 6 phase rectification is quite common, it is achieved using both a Star and a Delta secondary on the same transformer (often know as 6 pulse rectification). The direct output from the rectifier only has 4% ripple and is frequently used without any smoothing caps if a batttery is on the line (Aircraft transformer rectifier units).

Modern aircraft now use 18 pulse or higher rectification all in the name of reducing harmonics and improving power factor (at the expense of efficiency)

Ed

6 and 12 phase mercury rectifiers were used for many years in railway traction supplies. In the mid 80s I worked with the the silicon diode replacements that were being built for the London and Glasgow undergrounds.

There is a vast amount of information on the web try this link.

https://www.google.com.au/search?q=mercary+arcrectifier&oq=mercary+arcrectifier&sugexp=chrome,mod=0&sourceid=chrome&ie=UTF-8

i've been trying Google for years, lots of nice pictures but no "real" information.

This is why I asked if any of the older members had the "know how" on them. It's 35 years since I last worked on them and the memory isn't what it was.

Cheers Garth,

that should keep me quiet for a while. Unfortunately when we divorced my ex found all the vintage textbooks I'd acquired and sold them. How I miss them.

This should prove how good my memory is, or isn't and if I've got my drawing right.

Thanks, I sympathise,old text books are a valuable source of information, the internet does not have every thing available.