On the magnetic amp subject, I am just experimenting with testing the AVR3 by using a combination of a Lucas DC generator as a DC exciter and a Mag Amp set up to simulate the sine wave alternator.
It works good enough to save me re-commissioning my full size Gen set and using that!.

A small 1/3hp motor drives the Lucas genny and the mains power drives the magamp to get 50Hz.
The Lucas genny DC output drives the control coils on the magamp cores and varies the AC output.
The AC output drives back into the AVR and the points work across the field rheostat on the Lucas genny.

There are a few practical problems like the AVR3 does not like the crap waveshape of the magamp sine wave but it does work.
Still a work in progress at this point.
Fred.

Thanks for the information and insight Fred. It’s a fascinating subject AC power and generation and the effects of the reactive component within. The process of Synchronisation is quite amazing when observed directly especially with smaller generating sets. The way they lock to each and remain mechanically coupled to each other though the electrical connection is intriguing to say the least.

Way back when I was doing my E&C Cert (at night) we had a lecturer whose day job was in a power station. The discussion was what constituted "heavy" electrics. He gave an example:

Large turbine driving multi-megawatt generator. Coupling was two 40cm thick steel discs 2 metres diameter bolted together with 50mm bolts closely spaced all around the periphery.

If you made a mistake when bringing one of these on line, all the bolts would shear instantly with a huge bang.

Mr. Lenz would say "I told you that would happen."

My father's account of synchronising generators (up to 60MW max but dialled down to a fraction of that) before it went online involved very careful work with an oscilloscope, and frequency meters for the system and the generator. When the oscilloscope looked right (a circle) and the meters tallied as exactly as they could get it they would go for synchronisation. Even when closely matched there was always a slight bump from the unit as it went online. All a bit nervewracking with the shift engineer and perhaps other worthies looking over your shoulder.

As Ian says, get it wrong and things might fly about; and the steam without a job to do go out of the safety valve with a roar heard for miles around.

I have the part 3 of this series finished.
In this I assemble and test the AVR.
There will be a part 4 where I finish the project by making a housing for it and I do an article to submit to SC for the vintage radio section!

Will send the usual pdf to Brad to pin to the lead post.

Fred.

Part 3 uploaded.

I have the part 4 for this series finished and will pass on to Brad to put with the other parts.

This has been an interesting exercise delving back into the past and writing about times and technology that no longer exist.
If you are a reader of Silicon Chip you will have noted articles by Dr. Hugo Holden about forgotten tech.
Also note the series on the History of electronics and how much the basis of our lives now has come from "forgotten" tech!

I came into the work force just as "electronics" exploded based on microchips and all that and converted from "old school" to "new school" as a matter of course. As Dr. Hugo alludes these electronics are just a path we are walking, not the only path.
Thinkers like Tesla could sense elemental forces and tried to harness these with the electricity force.
He was done by about Y1900 and spent the last 40 years of his life bewildered and wound up a crazy old man not understanding why no one else could see what he could see. Sad.

Anway I'll condense this series and write an article for SC for the "vintage" section, who knows it may see print as an example of old school tech.

Fred.

Reading a book on Tesla at the moment:
Tesla Man Out of Time, Margaret Cheney, (Touchstone, Simon & Schuster).

Good at understanding stuff (eg originator of 3 phase generation, exploited by Westinghouse), but not making money out of it.

Part 4 uploaded.

I have reached the logical end to this topic by detailing some running of various solid state AVR's on the simulator rig.

As the running is done on existing PCB examples, I have kept for up to 30 to 40 years there were a few repairs needed.
Some of the AVR's I had no data about, I had to do a bit of back engineering to draw up circuits and see what the heck I was doing.
Luckily, I still have a drawer with transistors and SCR's from that era so I could replace the dud items.
The most prevalent fault was corroded legs on transistors!
Even a lot of the new old stock items looked pretty manky I just picked the best ones and soldered them in.
The steel legs just turn black and oxidise away!

Thanks to Brad for allowing me to post up these non-radio topics.
It has been cathartic to work on electronics and devices I made so long ago.
Probably may never return to the subject so I'll close the posts here and get back to vintage radio.

Will forward the final part to Brad.

Cheers, Fred.

Part 5 uploaded.

I believe the iron core material of transformers and motors was developed in USA and is a special "Silicon Steel"

Very enjoyable reading, a true time capsule in the practical sense, thanks Fred.

Regarding BC108's disguised as 2N3055's, that may explain why audio amps I built always had short life spans.