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Westinghouse fg-10

A tiddler! Modulating amplifiers for AM broadcast of 250KW and more were built. IIRC I linked to one here on pfm a few years back.... no I ain't searching for the post!
 
Do I see that right or does that thing actually have a door, so just in case you might want to see what's going on in your amp ?!
 
It does say that it is for driving industrial vibration test equipment, rather than HiFi.

I am unsure what I was expecting but I was surprised to see the vibration test kit at work, 10 or so years ago. I have no idea what the maximum load/sample weight would have been, but probably a couple of kg given what it was bought to test. The samples were basically strapped to the cone of a very large speaker, maybe 20 inch, maybe a little larger. The waveform generator and amplifier kit was old, but I don't believe that it was valve based, but it was at least as large as the cabinet on the link, probably a good bit larger, but then the link is just to the amplifier.

Why would anyone use valves these days, to run a vibration test rig???
 
Vinny said:
It does say that it is for driving industrial vibration test equipment, rather than HiFi.

I am unsure what I was expecting but I was surprised to see the vibration test kit at work, 10 or so years ago. I have no idea what the maximum load/sample weight would have been, but probably a couple of kg given what it was bought to test. The samples were basically strapped to the cone of a very large speaker, maybe 20 inch, maybe a little larger. The waveform generator and amplifier kit was old, but I don't believe that it was valve based, but it was at least as large as the cabinet on the link, probably a good bit larger, but then the link is just to the amplifier.

Why would anyone use valves these days, to run a vibration test rig???
Click to expand...

There may well be some valve ones still in use yes. It's not the sort of thing that changes much over the years or would be likely to be replaced often.
When power gets serious there is rather less to choose between valve and SS... Vapour cooled, water cooled etc high power valves can be amazingly compact for the huge powers they can give out.
Valves are still used in satellites, a TWT often, as the RF output stage!
 
I used to work with a electron-beam evaporator, which had 10kV 1A supply. The final stage in the supply used a big water cooled triode, made by Varian, which brought the output voltage down quickly for arc suppression. You could have done it with enough series connected solid state devices, but it would be complex and messy and have a much bigger parts count.

Mind you, there was a strict spec for water purity, as it had to be able to hold a 10kV voltage drop without too much leakage current. It meant we had an ion-exchange purifier cartridge connected in to the chlller loop, and tested water conductivity every day.
 
PigletsDad said:
I used to work with a electron-beam evaporator, which had 10kV 1A supply. The final stage in the supply used a big water cooled triode, made by Varian, which brought the output voltage down quickly for arc suppression. You could have done it with enough series connected solid state devices, but it would be complex and messy and have a much bigger parts count.

Mind you, there was a strict spec for water purity, as it had to be able to hold a 10kV voltage drop without too much leakage current. It meant we had an ion-exchange purifier cartridge connected in to the chlller loop, and tested water conductivity every day.
Click to expand...

I once worked on induction furnaces, which used SCR's as the switching elements. These were water cooled and had the same set up you describe. In fact a built in self test would continually check the water purity.
 
Eimac were the division of Varian that make big tubes. You can find a 1975 catalogue here https://frank.pocnet.net/other/Eimac/Eimac_1975_Quick-Ref.pdf.

The one I used was something like the part on page 48, 3CW20,000A1 (or similar, might have been a newer model by the time we bought the kit).

They made much bigger ones - look on page 53, at the X-2176, intended for megawatt scale industrial heating. Uses 20kV B+, and 125A of plate current.
 
I'm easily pleased - I'd simply like to find a duff 833A or similar, to use the filament as a night-light/ desktop heater...
 
Interesting stuff. As said, once you get away from the mV and very few volts that SS operates at...……………….

I have worked with and around almost countless induction systems and low volt, very high current heaters, to the extent that water-cooled cables were essential, but never been curious about the power supplies/controllers. VERY reliable though as I don't recall anything ever failing on the electronics side of things, it was always the mechanical side/hardware that gave problems.
 
Vinny said:
I have worked with and around almost countless induction systems and low volt, very high current heaters, to the extent that water-cooled cables were essential
Click to expand...

my emphassis - that sounds like there's a story or two that's be interesting!

(I collect such things - An old friend related some interesting stories about accurately measuring a 10kA shunt... amongst other professional trials)
 
The induction heaters that I am most familiar with were used for firing getters (on lamps, not valves, not that that makes any difference whatsoever), the HF induction coils were actually annealed copper pipe as used for micro-bore central heating and were fed with chilled water.

The 3 inch diameter water-cooled cables fed a small furnace (around 15cm diameter and high) in an argon atmosphere where the element was a tungsten mesh - like chainmail. That furnace ramped up and cooled VERY fast. There were ammeters on the control panel, but they were not something that I needed to know about - ramp rates and dwell times were what I determined and set. The furnaces produced VERY precisely dimensioned glass seals in ceramic lamp arctubes.
 
Ah yes water cooled flexible cable is something I've seen in the same context... 3 cables, one for each phase, and they jump several inches when power is applied!
 
The water-cooled cables on the HF gear that I am familiar with weren't huge, maybe 30mm or so. Precisely what was water-cooled in the whole system, I don't know, but chilled water cooled some of the electronics (again I know not what precisely, SS or valves - Inductelec units from pre 1970 I would guess, in the main).
The front of the control cabinets generally had two glass tube rotameters/float gauges to show water flow rate, when they weren't too green with algae.

P.S. Just checked Inductelec - STILL in business in Chesterfield!!!!! Amazing, surviving UK manufacturing. Where their kit is actually made though...…..

Some relatively crude water-cooled copper pipe inductors -

https://www.inductelec.co.uk/induction-heating-coils
 
These are mere toys.

Before becoming a civil servant in 1970 I worked for a company called Derritron Electronics. We built huge shakers/vibrators driven by equally huge valve amps up to 36kW. At the time they were the biggest in the world and much in demand for testing aircraft and missile parts in the defence and aerospace industries. We sold them all over the world including Russia and China, much to the consternation of the USA. I remember at the height of the 1969 Ussuri River Incident being given the job of making sure that members of visiting trade delegations from the USSR and the PRC did not met each other on the factory floor! Happy days!
 
wlw7.jpg


Call that an output transformer? /\ THAT'S an output transformer! One of a pair used together to give up to 250,000W of audio to modulate a 500,000W AM transmitter in the '30's.
 
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