A tip o' the hat to Australian reader Snoggeramus for sending me the link to this news report.
Excavators in Brisbane have unearthed 134-year-old electrical cables known as "Edison tubes" under a CBD street, revealing the city's earliest power grid.
Designed by inventor Thomas Edison, the tubes date back to 1884, when they were laid beneath William Street to supply electricity to the parliamentary precinct.
. . .
Sections of the cables will be housed in London's Science Centre, the Thomas Edison National Historical Park in New Jersey, Sydney's Powerhouse Museum, Commissariat Store Museum in Brisbane, the Highfields Pioneer Village in Toowoomba, as well as Parliament House.
"The legacy will be to show future generations how manufacturing occurred of electrical cables in the 1880s," [retired electrical engineer Brian] Beckinsale said.
"It was very difficult to actually construct, with the steel pipe and copper conductor down the inside and insulation in 20-foot [6.1-metre] lengths."
At the time they were invented, Edison decided 6.1 metres was the maximum length horses could carry as the tubes were transported across the laneways of New York.
There's more at the link, including photographs of the 'tubes'.
It's fascinating to read about those cables, the first ever designed to conduct power commercially from a generating station to the end user. In particular, at this distance from that period in time, we forget that horses were still the prime movers of their day. Internal combustion engines were not yet a factor. Everything was carried on wagons, pulled by horses or oxen. It seems very odd to our modern minds to have electric lights in a building that was served by animal transport only . . . but that's how it was at the dawn of the "electrical age".
Peter
Interesting. Edison was a strong proponent of Direct Current, so I'm guessing these "Edison tubes" were designed and constructed to support DC. The article didn't mention it, but I'd be curious as to what the design was to support how many amps of DC at what voltage.
ReplyDeleteYeah, I'd be interested in the voltage and amperage as well.
ReplyDeleteI suspect it was very high. High power DC would heat the cables a bit which means that the received power would be quite a bit lower at the end. More importantly there would be a pretty large voltage drop given the resistance of the cables.
When the Port Authority of NY/NJ was replacing the circa 1904 float bridge in NJ used to transfer rail cars to a ferry to transfer them to Long Island, the antiquated electrical system was hauled away as historic artifacts. They'd been designed by Edison and fabricated by his company way back when, and were still running as a 420 VDC. They'd deteriorated a bit over they years, though, such that those operating the system stood well clear when they flipped the switch, so as not to be showered upon by the rain of sparks.
ReplyDeleteFascinating! Thanks for sharing.
ReplyDeleteWe are not yet two centuries from major realization of the linkage between electricity and magnetism that made our modern world possible.
ReplyDelete"The recognition of electromagnetism, the unity of electric and magnetic phenomena, is due to Hans Christian Ørsted and André-Marie Ampère in 1819–1820. Michael Faraday invented the electric motor in 1821, and Georg Ohm mathematically analysed the electrical circuit in 1827."
DC had a the big problem of voltage drop as loads were attached so the people far from the power station got very different service, even at high, dangerous voltages. Not to mention, until modern switching electronics, DC could not be easily relayed or transformed from high to low voltage, low to high amperage.