Comments on: Amazing Vacuum Tubes May Eliminate Motors (Aug, 1931)

By: John Savard

John Savard — Wed, 16 Sep 2009 13:29:53 +0000

While we still use motors to move things, in at least two ways the article did show the future correctly. Diathermy was illustrated, and, of course, that illustrated the principle later employed in the microwave oven.

Also, while they didn’t end up using thyratrons for HVDC power transmission, later solid-state technologies were applied to it.

The reason we use AC instead of DC for power is because, with transformers, it’s easy to change the voltage level of AC electricity. With a higher voltage, resistive losses are lowered as a simple consequence of Ohm’s Law.

But just as AC can travel through a transformer, or emit radio waves, while resistive losses are lowered by using a high voltage, AC in a power line is still inductively coupled to the environment. So the ideal method of power transmission would be to use very high-voltage DC instead, to minimize both kinds of losses. We now have efficient enough ways to convert between AC and DC to make it practical to convert high-voltage AC to high-voltage DC for certain selected long-distance transmission lines – and then convert it back to AC so that the voltage can be changed to something much lower that is safer to use.

By: Nomen Nescio

Nomen Nescio — Wed, 16 Sep 2009 00:06:29 +0000

30 meter wavelength works out to about 10 MHz. so i guess they weren’t technically microwaving their patients, that’s not in the microwave band yet. still, i’m happier staying outside any EM/RF fields capable of measurably heating my bodu up…

By: Firebrand38

Firebrand38 — Tue, 15 Sep 2009 22:58:27 +0000

Maybe it’s diathermy http://emedicine.medscape.com/.....6-overview as well as inducing a fever through “heating” rays http://en.wikipedia.org/wiki/F.....s_of_fever

By: A johnstone

A johnstone — Tue, 15 Sep 2009 22:35:06 +0000

Huh, that’s interesting stuff, I stand corrected.

I still can’t quite swallow the stuff about healing rays. And increasing the senses?!? Maybe it’s just sensationalism.

By: Firebrand38

Firebrand38 — Tue, 15 Sep 2009 22:29:51 +0000

ligu: Good catch! And it also ties in with the whole thyristor article as well!

By: ligu

ligu — Tue, 15 Sep 2009 22:12:52 +0000

The article is correct, actually. AC can only be transmitted for a couple of hundred miles. For very long distances, high voltage DC is used. See: http://en.wikipedia.org/wiki/HVDC

By: Firebrand38

Firebrand38 — Tue, 15 Sep 2009 20:28:41 +0000

Actually Westinghouse pioneered AC. General Electric was associated with Edison who championed DC.
http://en.wikipedia.org/wiki/G.....ic#History

I don’t think its a spoof, either a misquote or marketing propaganda

http://en.wikipedia.org/wiki/War_of_Currents

By: A Johnstone

A Johnstone — Tue, 15 Sep 2009 19:57:20 +0000

Yeah this is a spoof. By this time it was common knowledge that AC travels long distances with nominal loss, not DC. Especially GE, the company that pioneered AC.

Amusing article tho, if you look at it in the climate of groundbreaking innovations around the turn of the century. I suppose it could even be an oblique dig at mr. tesla.

thoughts?

By: Firebrand38

Firebrand38 — Tue, 15 Sep 2009 18:25:29 +0000

Tracy Blomgren: And who are “they” this time?

By: Tracy Blomgren

Tracy Blomgren — Tue, 15 Sep 2009 18:16:46 +0000

Now they use thyristors; silicon controlled rectifiers and triacs

By: DrewE

DrewE — Tue, 15 Sep 2009 17:26:25 +0000

There were a few mercury vapor/steam power plants built and operated commercially. One online refernece (with pictures and so forth–scroll down a spell) is http://www.dself.dsl.pipex.com.....ercury.htm

By: John

John — Tue, 15 Sep 2009 16:11:50 +0000

I wouldn’t want to be around those pipes of high pressure mercury vapour when they spring a leak.

By: rick

rick — Tue, 15 Sep 2009 15:07:36 +0000

The mike and phonograph setup for soothing the baby reminds me of something you’d see in a Wallace and Grommet movie.

Rick