16 Feb
2008
16 Feb
'08
4 p.m.
From: "Gavin Melville"
I had looked at relays, and while there certainly were
relays in 1900, I
doubt they were very good in terms of bounce, actuation time etc. The
building where I work has an Otis made lift dating from 1980, done
completely with relays. It's fairly unreliable, and a lot of the relays
have to be fiddled with springs, copper disks, iron slugs etc. (Some of
them were designed that way, and some just needed it to make them work).
As a counter-example, consider the Panama Canal, opened in 1914. All-
electric run from a central control pulpit. With control circuitry
designed by Edward Schildhauer, the equipment is still in service
today, though it's due to be replaced. Relays and primitive servo
motors were part of the whole affair. (BTW, some 1,500 electric
motors are involved in the operation. I recall seeing a photo of
some of the control circuitry--brass and varnished wood. It was a
thing of beauty.)
Cheers,
Chuck