[time-nuts] Daft idea with the National Grid

[John Moran, Scawby Design]

On Sun, 7 Feb 2021 20:45:57 -0800
Jim Lux said -


"If you happen to own something like a steel mill running electric

furnaces or an aluminum refinery, so you can manipulate the load..."

Sometime in the late '80s, my first decent sized computer system came on line at a telecom factory in England. It ran fine for a few days then crashed. Rebooting made it run fine for another 7 days then it crashed again, and then every 7 days at almost the same time - like a very poor clock. Monitoring the mains voltage with an expensive hired monitor showed a huge drop in voltage lasting about ten seconds at the relevant time.

It turned out that the biggest steel rolling mill in Europe was only 5 miles away and they were testing new motors on the rolls. We had some interesting visits and talks with them and persuaded them to turn the motors on one by one instead of in batches and, in conjunction with some hefty mains filtering, the problem went away.

That sort of load step must have been noticed by the electricity suppliers, and half the computers in the city!

John