In those old computers that used hundreds of tubes.. .like at Bletchley Park...
Where did they get all the current from.?
They run on 12 or 6 volts nominally.
How did they deal with that.?

Thank You

https://images.search.yahoo.com/yhs...ratory,universityofcambridge.jpg&action=click

 

The only tube based digital device (from the 50's) I worked on used special miniature tubes with about 1.25v for the heaters.
https://forum.allaboutcircuits.com/threads/some-questions-about-vacuum-tubes.80047/post-568101


Tube voltage meter.
https://www.google.com/url?sa=t&sou...0QFnoECBQQAQ&usg=AOvVaw0rPfC9AhKwzrYsQYzceox7
https://en.wikipedia.org/wiki/KW-37

 

They had multi-secondary windings on the transformers.

 

Many tube heaters were run on AC directly from transformers connected to the mains. When you drop the voltage, you increase the current, so the power remains approximately the same allowing for some losses.

 

I can’t find information on Colossus, but ENIAC, the first general purpose computer, consumed 150 kW. Much of this power was dissipated as heat, and a similar amount of power was additionally consumed by the air conditioning.
Early computer centers were extremely power hungry!

 

I can’t find information on Colossus, but ENIAC, the first general purpose computer, consumed 150 kW. Much of this power was dissipated as heat, and a similar amount of power was additionally consumed by the air conditioning.
Early computer centers were extremely power hungry!

Yeah..... Good Heavens.

I am used to amps with.....5 to 10 tubes
Maybe 3 to 10 amps for the filaments.?
A machine with 10 - 15 - 20 - 30 times that number must have had a voracious appetite for current

 

Yeah..... Good Heavens.

I am used to amps with.....5 to 10 tubes
Maybe 3 to 10 amps for the filaments.?
A machine with 10 - 15 - 20 - 30 times that number must have had a voracious appetite for current

It depends on the type of tube.This last generation of tube digital gear had manageable power requirements.
The KWR-37 had 500 6088 tubes with a filament voltage of 1.25V and 20mA of heater current per tube. Plate voltage of ~45VDC with 1mA of total plate current.
One of three (each with several hundred tubes) sanitized (no classified boards) KWT units.The schematic was classified SECRET CRYPTO and I don't think it was ever declassified.
The three separate encoder bitstreams were compared and could vote one unit as being wrong, and then switch to mirror mode for two encoder unit verification of the encrypted data stream until one of those two failed or the third unit was repaired, resynchronized using the setup timing knob/button and switched back to normal mode. All without skipping a bit. A very impressive feat of electrical engineering from the 50's that was in use until the 90's (very EMP resistant)..


It was heavy but the PS was in the upper cabinet.

 

The home-made tube computer at the U. of Wisconsin, when I was there, had about 15,000 tubes and consumed about 15kW,as I recall.

The KWR-37 had 500 6088 tubes with a filament voltage of 1.25V and 20mA of heater current per tube. Plate voltage of ~45VDC with 1mA of total plate current.

That's amazing low power requirements for a tube.

 

In those old computers that used hundreds of tubes.. .like at Bletchley Park...
Where did they get all the current from.?
They run on 12 or 6 volts nominally.
How did they deal with that.?

Thank You

https://images.search.yahoo.com/yhs/search?p=Bletchley+Park+computer&fr=yhs-iba-3&type=teff_10019_FFW_ZZ&hspart=iba&hsimp=yhs-3&imgurl=https://garymjones.com/wp-content/uploads/2020/11/bletchley-25-1.jpg#id=10&iurl=https://ichef.bbci.co.uk/news/1024/media/images/50779000/jpg/_50779618_edsca,computerlaboratory,universityofcambridge.jpg&action=click

Colossus used EF37 valves, which have 6.3V heaters. So it was just a transformer for each module.
As for any filament lamp, a low voltage heater supplied by a transformer is more reliable than a high-voltage heater of the same power.
6.3V was originally chosen because it was 3 lead-acid cells, but Colossus was mains powered so would have AC heaters.

 

The power came from the mains, just like today. And the transformers were indeed impressive. six volts AC at 45 amps was available before they needed fan cooling. 3 strands of #12 scc enameled wire because the heavier stuff was miserable to wind.

 

I was around using and building valve based equipment in the '50's.
I recall building a multi-type tube/valve tester for myself, I rewound the secondary of a large transformer that provided switched-in a selectable Valve HTR voltage.

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