3 ms·
Equipment being out of phase has nothing to do with the timing. The timing of the 50/60 Hz signal actually changes throughout the day. On average the signal ove
by X-Istence 13y ago
Equipment being out of phase has nothing to do with the timing. The timing of the 50/60 Hz signal actually changes throughout the day. On average the signal over 24 hours will equal about 24 hours so you can keep time with it, but as the load changes on the grid it will actually slow down and then speed back up when people turn off their devices at night.
The phases of the grid as a whole actually get synched up automatically. For example when they spin up a new turbine at a power plant if it is not within a certain percentage of the phase cycle it can actually cause massive amounts of damage as it gets pulled into the phase automatically.
The electric grid companies actually want to lower the current requirements for the 50/60 Hz cycle to be accurate in a 24 hour period to longer, such as possibly a week. This could mean that the clock in your oven for example may be a minute or two slow and slowly catch up over time as the grid has moments where it is clocked faster than 50/60 Hz.
For example see this graph of the last 60 minutes: http://www.nationalgrid.com/uk/Electricity/Data/Realtime/Frequency/Freq60.htm http://www.nationalgrid.com/uk/Electricity/Data/Realtime/Fre... and here it is in real time for the whole US: http://fnetpublic.utk.edu/gradientmap.html http://fnetpublic.utk.edu/gradientmap.html
And here is the experiment that the power companies wanted to run/still are running regarding the relaxing of keeping the grid at 60 Hz: http://www.nbcnews.com/id/43532031/ns/technology_and_science-innovation/t/power-grid-experiment-could-confuse-electric-clocks/#.UnHxapF0UXo http://www.nbcnews.com/id/43532031/ns/technology_and_science...
- gk1 13y ago> as the load changes on the grid it will actually slow down and then speed back up when people turn off their devices at night. When I sailed on ships we knew not to use alarm clocks that plug into an outlet, because the load on the ship's generators is always changing, thus making plug-in alarm clocks less dependable than wrist watches.
- X-Istence 13y agoThis is also the reason why a lot of clocks like that won't work on inverters that convert 12 VDC to 120 VAC since any load and most of them fall below spec.
- cnvogel 13y agoFor reference, the specification for the European power grid is in the "Continental Europe Operation Handbook", Part "P1, Load-Frequency Control and Performance". https://www.entsoe.eu/publications/system-operations-reports/operation-handbook/ https://www.entsoe.eu/publications/system-operations-reports... It's actually a pretty elaborate system (who would have guessed?) with phase-stiffness between subsystems specified, because this basically defines the amount of power drawn/sourced. Timing is just the "outermost" regulation loop.
- epsylon 13y ago> On average the signal over 24 hours will equal about 24 hours so you can keep time with it, but as the load changes on the grid it will actually slow down and then speed back up when people turn off their devices at night. Yes, the load changes the frequency over the course of a day. In Great-Britain there's even a special peak after the afternoon TV shows finishes and people start turning on their electric kettles to prepare tea. http://www.bbc.co.uk/britainfromabove/stories/people/teatimebritain.shtml http://www.bbc.co.uk/britainfromabove/stories/people/teatime... In fact, the exact frequency of the power grid can be used to identify precisely the time of the day! http://en.wikipedia.org/wiki/Electrical_network_frequency_analysis http://en.wikipedia.org/wiki/Electrical_network_frequency_an...
- X-Istence 13y agoThat is really cool that they can use it as a sort of fingerprint!