[time-nuts] 60 Hz frequency and phase measurement

[Thomas D. Erb]

We have used line frequency counting for time keeping in the past  it works very well in the USA - EXCEPT in locations with lots of dimmers - theaters in particular chop the AC waveform creating lots of noise and can make the internal timer run fast.  I think at one location we had 5 volts of noise on the mains. TXO chips just always work - so we use them now, or GPS.

I had a recent tour of a power station - the operators had no idea the output was synchronized to a time standard - they just synchronize with the local grid.

For a history of line frequency time keeping, Wikipedia has a good entry.
https://en.wikipedia.org/wiki/Telechron

Though Tesla I believe demonstrated this at the Chicago World's fair.

I have a master in my small museum.
https://electricclock.omeka.net/items/show/12





Thomas D. Erb
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Tower & Street Clocks Since 1928