The AM Forum

We have a 4CX5000A/8170 tube,
 with all the transformers, Magnetics, socket,  caps ...etc. etc...saved for a long time. It actually is everything from a 6KW system.
 Thinking...of linear amp configurations and designs for this tube if we decide to build an amplifier with it. Plenty of data sheets, factory info. etc. out there.
Looking through information on designs, looking through the sites for builds and ideas. Fun. Maybe its time to think about doing something with this stuff.
Anyway, having fun thinking about it right now.

Have been looking at a lot of "Grounded Screen", Grid driven, Class AB1 designs for Linear Amps.
Seems to be some classic designs out there.
 Looking at : "John 5-19 Lamia",  Interesting construction of homemade Linear using 4CX5000A tube.
https://5-19lamia.blogspot.com/

Anyway,
 Plate modulated AM transmitter for this tube...have to think about that, Linear sounds much simpler right now.
Still having fun looking at the parts and thinking about it for now.

That 'jug' has some serious business to it! But an awful lot of electrons pass through it to keep the filament happy! I think I would lash it up first as a linear and drive it with a Ranger of 'transmitter-de-jour' without worrying about going to far with it. I thought Rich Measures, AG6K(SK) built one and it worked pretty good.

A plate modulated 4CX5000A would be the cat's tookus!
Seeing as how you've already got the iron and sockets and such, you've got quite a leg up already.
Since the parts came from a transmitter, does that mean you have the modulator tubes and iron as well?
Wow...assuming running this thing full-strap, you're looking at roughly 3500 watts of audio!

I will post more information on what we have here. Also, have a transformer question, trying to get a few pictures together.

few pics

pics

Here goes....will try to keep this short.
This unit is an Electron Beam Power supply for EB Evaporation (Physical Vapor Deposition system, Thin Film Deposition) .
(6 KV) NEGATIVE DC output. from late 1990's. 
SO,....
We have the filament transformer (AC), 4CX5000A tube w/socket, Rectifier assy. diodes, etc. , HV Transformer, caps, etc. etc...much stuff.
The tube ,of course, is designed for radio, (RF).
However,
this HV transformer /Rectifier circuit unit build as NEGATIVE DC,
easily changed to POSITIVE HV DC. (Isolated socket, etc...)
to supply the HV Positive DC.
You get the idea.
The main question is:
This 3-phase HV transformer (we can run it 3-phase if need be.)
It is made of (3) separate, independent coils/windings on a common core (Si-Iron).
3-separate outputs combined with buss-bars, bussed together.
Question...:
Is there any reason we could not simply use the center winding only?
As a single phase transformer or is the core "TOO big" ?
We want to lower the power levels to Legal Limit Amateur Radio levels.
What do you guys think???
AG5UM

PS...oversimplified the transformer output for simplicity in  explanation.
Typically 3-phase HV transformer feeds the 3-phase full wave rectifier circuit, which is an advantage in its application for e-beam...etc.
There are design variations.

 
 deleted this comment, for now.
Still looking it all over.

There are those with a more intimate knowledge of transformer design than I, but my feeling is that using only one winding on single-phase would result in some serious inefficiency and corresponding heat, due to the magnetic eddy currents flowing around in the remainder of the laminations. It might even generate some dangerous voltages in the unused windings, since they wouldn't be loaded.

If using anything other than the full set of windings, you might be better off using two of them, one side of each connected to opposite legs of your 240V single-phase line and the other two sides to neutral.

Proper phasing would be crucial, and experimenting with various configurations using a variac to "tickle" the windings would probably be advisable.

A better approach, I would think, might be to generate your own three-phase using a solid-state phase converter, or VFD, or maybe a rotary phase converter.

Thanks for the response, suggestions.
The internet search comments I deleted in the previous post were  similar. Internet search:
They say, transformer core issues, magnetic imbalance, driving only one leg creates magnetic imbalance leading to core heating...etc.
Derating, even if you connect single phase across 2-legs (line to line) of primary, typically can only use about 58% of transformer's rated capacity without overheating...etc.
It says if only have single phase, connect single phase source to 2 of the 3 primary input terminals (line to line) etc. etc.
Use a Phase Converter. Rotary Phase converter, Variable frequency drive. Internet also suggest a Bridge using four 866A vapor tubes...
We have the capability to run it 3-phase if needed.
It seems using only one winding is not a good idea even for testing only.
Thanks for comments.