[time-nuts] Re: Power line timing -- setting a clock

[Erik E. Fair]

At The Exploratorium science museum in San Francisco, there's an exhibit demonstrating the physical power behind electricity generation and the requirements of various loads: a park bench with three or four bicycle pedals in front of the spaced seats of the bench, hooked together to drive a dynamo, and at eye level, a circuit powered by that dynamo with various loads that can be added in parallel: incandescent lightbulb, AM radio, electric fan, etc.

https://www.exploratorium.edu/exhibits/pedal-generator

The more load you turn on, (surprise) the harder you have to pedal. It's a very visceral demonstration that there's real power behind apparently otherwise insubstantial electricity.

Missing from this exhibit (and of time-nuts relevance) is the frequency synchronization required for a dynamo generating AC power to connect to an AC grid - if they're not properly frequency synchronized, the frequency mismatch can physically damage the "incoming" dynamo. I've been told that if the frequency mismatch is bad enough (not just exactly 60 hz, but also same peaks & valleys - in phase), grid power will tear the dynamo apart.

Once a grid has decided on a frequency, everyone in it has to keep to it, or bad things can happen.

https://gridradar.net/en/blog/post/underfrequency_january_2021

https://www.next-kraftwerke.com/energy-blog/who-is-disrupting-the-utility-frequency

To the extent that clocks use grid frequency as the oscillation base for the
counters that make a clock ...

	Erik