[eDISCO]

Most traditional generators (think CCGT, nuclear, hydro) run in synchronous mode. Which means the generators spins with rpm proportional/equal to the network frequency. For 50Hz that would be 3000rpm. When the total electricity demand exceeds the supply, the kinetic energy of spinning generators is converted to electricity which slows down the generator rpm, which reduces the frequency. All synchronous generators on a given network spin at the same frequency, so when the demand is too high all of them slow down a bit.

[karamitru]

There was a comment once on HN that once a power generator was hooked to the network without the phases being aligned, and the resulting mechanical forces were so large that the generator got unbolted from the floor and flew through the air. Not sure if true or not.

[generatorguy]

It could well be true, This has happened many times

[circular_logic]

That makes me wonder, if you were standing next to these turbines would you be able to here them slow down?

[fanf2]

The change in pitch from 50Hz to 48.8Hz was 0.4 semitones.

12 * ln 50 / ln 2 = 67.7

12 * ln 48.8 / ln 2 = 67.3

[kalleboo]

This is kinda unrelated (it involved a line frequency slowdown from 60 Hz to 51 Hz), but I always found this radio recording of the US northeast blackout of 1965[0] fascinating as the DJ is grappling with records/tape cartridges slowing down and lights dimming live on the air https://www.musicradio77.com/images/ing11-9-65blackout.mp3

[0] https://en.wikipedia.org/wiki/Northeast_blackout_of_1965#Rad...

[mnx]

If I listen carefully, I can tell the difference between 48 and 50hz using a sine generator (although it's very subtle), so I'd guess that you possibly could.

[bsder]

Probably, although you are more likely to hear the 3000Hz to 2880Hz change in the generator RPM than the 50 to 48.8 change in the output.

[Iwan-Zotow]

Yes