8 ms·

A difference in frequency is much less of an issue than a difference in voltage, I would have thought. Especially as 50 and 60Hz are fairly close to each other.

A difference in frequency is much less of an issue than a difference in voltage, I would have thought. Especially as 50 and 60Hz are fairly close to each other. The only big problems I can think of are devices that use the frequency as a reference, such as motors and clocks. But even then, they wouldn’t break, they’d just run at the wrong speed.

rrr_oh_man 2y ago
> The only big problems I can think of are devices that use the frequency as a reference, such as motors and clocks. This was my March mindfuck: That there are periods every couple weeks when the WHOLE ELECTRICITY GRID of a country is run with higher/lower frequency for a period of time to get your Chinese oven clocks back into sync.
- lxgr 2y ago
  Long-term grid frequency stability is something you take for granted, until it suddenly fails, like in most of Europe back in 2018, due to a political disagreement between Serbia and Kosovo: https://www.reuters.com/article/idUSL5N1QP2FF/ https://www.reuters.com/article/idUSL5N1QP2FF/ I also find it quite funny that our cheap oven clock is probably among the most precise (non-internet connected) ones in our apartment :)
  - Scoundreller 2y ago
    WWVB de-rating has got us all a bit down in North America. Lots of consumer level “atomic clock accuracy” devices just don’t update any more. https://www.watchuseek.com/threads/wwvb-operating-with-reduced-power.5564472/ https://www.watchuseek.com/threads/wwvb-operating-with-reduc...
    - toomuchtodo 2y ago
      It’s a shame there aren’t more time tower sites broadcasting in a distributed manner for redundancy.
      - Taniwha 2y ago
        Noted my car got time from GPS the other day and it got me thinking, why aren't there unencrypted packets on all wifi that distribute NTP time so my oven/microwave/alarm/etc can grab it from any wifi it can see (even if it's not paired to them) - bonus points if APs also hand out local TZ data
        joha4270 2y ago
        Phone networks can already do this. And its true broadcast, you can decode it passively without ever connecting to the network, so no SIM/transmission required. I have no idea this is actually enabled in networks in practice, but the specification exists.
        cesarb 2y ago
        And in my experience, it's often wrong on some towers. I can't enable the setting on my phone to automatically set the time from the network, because if I do, it gets several minutes out of sync with the real time, which breaks TOTP generation.
        lxgr 2y ago
        Yeah, a large German cell provider had their time off by a couple of minutes some years back, which made the news as it resulted in people's alarms ringing late and them being late to work/school etc. Hopefully modern phones prioritize GPS or NTP derived time and timezone information over NITZ (which is how networks provide it). At least Android has the capability to do so, but it's ultimately up to device manufacturers, as far as I understand [1]. [1] https://source.android.com/docs/core/connect/time https://source.android.com/docs/core/connect/time
        toomuchtodo 2y ago
        Could the detection and reporting of this inaccuracy be crowdsourced, either with mobile devices or perhaps SDRs? Fetch tower time, fetch real time over GNSS or NTP, report delta with tower ID and drift to a central server? Perhaps even include a map, like the map of GPS error rates derived from ADS-B data feeds. Related: https://news.ycombinator.com/item?id=39771354 https://news.ycombinator.com/item?id=39771354
- AdamH12113 2y ago
  It's surprisingly hard to keep a clock accurate over time. Typical crystal oscillators can gain or lose seconds per day. If you want to do better than that, you either need internet access (for NTP), a radio receiver of some kind (for atomic clock broadcasts, GPS, etc.), or a significantly more expensive oscillator. Having a frequency reference with perfect long-term accuracy that any electrically-powered clock can use for free is pretty convenient! I've often wondered how hard it would be to make portable battery-powered clocks use 60 Hz noise as a timekeeping source. Maybe I should make a project out of it.
  - deleted 2y ago
    [deleted]
  - rrr_oh_man 2y ago
    > Typical crystal oscillators can gain or lose seconds per day. Are you sure? I only owned a quartz watch when I was a kid, but all sources I find on the web say even the lowest quality quartz watch movements are accurate to +- 20-30 seconds a month. For comparison: my several decades old manual Poljot loses some seconds per day.
    - AdamH12113 2y ago
      The Casio G-Shock I got in the 90s was ~66 ppm fast, which worked out to ~5 seconds/day. There are cheap crystals on Digi-Key with ~10 ppm accuracy, which is around 0.86 seconds/day. But crystals drift with age (and a tiny bit with temperature). Perhaps watches have improved since I last looked, but I would want to measure the actual real-world accuracy before believing anything better than 1 second/day.
    - crote 2y ago
      Yeah, that sounds about right. Crystal oscillators typically have an accuracy of about 20ppm, which is 1.73 seconds per day. Keep in mind that those number are a guaranteed worst-case performance - real-world performance is often much better.
  - agos 2y ago
    how more expensive is a "more expensive" oscillator?
- Taniwha 2y ago
  There used to be a local hydro generation that fed the local city, they had 2 clocks on the wall, one on the local grid and one on the national one - some time late at night they'd speed up/slow down the local grid to keep the clocks in sync
pezezin 2y ago
A difference in frequency is not that big of a problem... except for the fact that you can't easily transfer power across the two grids. Japan has some power conversion stations, but when the Tohoku earthquake and tsunami of 2011 knocked off several powerplants in the 50 Hz half of the country (including Fukushima), they could not transfer enough power from the other side, and the suffered many blackouts, even though the 60 Hz half of the country had power to spare.
- johannes1234321 2y ago
  > A difference in frequency is not that big of a problem... except for the fact that you can't easily transfer power across the two grids. And for everything, which uses the frequency as a clock.
  - pezezin 2y ago
    True. Nowadays it is not a problem, but it makes me wonder how they could make 60 Hz television run on a 50 Hz grid.
    - lxgr 2y ago
      I've been wondering that too recently, and apparently it wasn't that big of a deal [1] – more recent analog TVs weren't that susceptible to mains interference of the sort that benefited from being synchronized to the frame rate. In other words, the mains frequency was never used as a frequency source for TVs, and the apparent frequency match was only to make interference patterns not wander around the screen. [1] https://electronics.stackexchange.com/questions/164249/is-the-design-decision-for-different-frequencies-in-pal-and-ntsc-related-to-the https://electronics.stackexchange.com/questions/164249/is-th...
lxgr 2y ago
A motor running at 20% higher/16% lower speeds might break some things, I could imagine?
- quickthrowman 2y ago
  If the motor is designed for it, then no. Many motors these days are built to handle variable frequencies on account of VFDs A variable-frequency drive is a motor controller that adjusts the frequency of the power delivered to a motor to speed it up or slow it down. It could possibly damage a motor that isn’t designed for use with a VFD. https://en.m.wikipedia.org/wiki/Variable-frequency_drive https://en.m.wikipedia.org/wiki/Variable-frequency_drive

rrr_oh_man 2y ago

> The only big problems I can think of are devices that use the frequency as a reference, such as motors and clocks. This was my March mindfuck: That there are periods every couple weeks when the WHOLE ELECTRICITY GRID of a country is run with higher/lower frequency for a period of time to get your Chinese oven clocks back into sync.

lxgr 2y ago
Long-term grid frequency stability is something you take for granted, until it suddenly fails, like in most of Europe back in 2018, due to a political disagreement between Serbia and Kosovo: https://www.reuters.com/article/idUSL5N1QP2FF/ https://www.reuters.com/article/idUSL5N1QP2FF/ I also find it quite funny that our cheap oven clock is probably among the most precise (non-internet connected) ones in our apartment :)
- Scoundreller 2y ago
  WWVB de-rating has got us all a bit down in North America. Lots of consumer level “atomic clock accuracy” devices just don’t update any more. https://www.watchuseek.com/threads/wwvb-operating-with-reduced-power.5564472/ https://www.watchuseek.com/threads/wwvb-operating-with-reduc...
  - toomuchtodo 2y ago
    It’s a shame there aren’t more time tower sites broadcasting in a distributed manner for redundancy.
    - Taniwha 2y ago
      Noted my car got time from GPS the other day and it got me thinking, why aren't there unencrypted packets on all wifi that distribute NTP time so my oven/microwave/alarm/etc can grab it from any wifi it can see (even if it's not paired to them) - bonus points if APs also hand out local TZ data
      - joha4270 2y ago
        Phone networks can already do this. And its true broadcast, you can decode it passively without ever connecting to the network, so no SIM/transmission required. I have no idea this is actually enabled in networks in practice, but the specification exists.
        cesarb 2y ago
        And in my experience, it's often wrong on some towers. I can't enable the setting on my phone to automatically set the time from the network, because if I do, it gets several minutes out of sync with the real time, which breaks TOTP generation.
        lxgr 2y ago
        Yeah, a large German cell provider had their time off by a couple of minutes some years back, which made the news as it resulted in people's alarms ringing late and them being late to work/school etc. Hopefully modern phones prioritize GPS or NTP derived time and timezone information over NITZ (which is how networks provide it). At least Android has the capability to do so, but it's ultimately up to device manufacturers, as far as I understand [1]. [1] https://source.android.com/docs/core/connect/time https://source.android.com/docs/core/connect/time
        toomuchtodo 2y ago
        Could the detection and reporting of this inaccuracy be crowdsourced, either with mobile devices or perhaps SDRs? Fetch tower time, fetch real time over GNSS or NTP, report delta with tower ID and drift to a central server? Perhaps even include a map, like the map of GPS error rates derived from ADS-B data feeds. Related: https://news.ycombinator.com/item?id=39771354 https://news.ycombinator.com/item?id=39771354
AdamH12113 2y ago
It's surprisingly hard to keep a clock accurate over time. Typical crystal oscillators can gain or lose seconds per day. If you want to do better than that, you either need internet access (for NTP), a radio receiver of some kind (for atomic clock broadcasts, GPS, etc.), or a significantly more expensive oscillator. Having a frequency reference with perfect long-term accuracy that any electrically-powered clock can use for free is pretty convenient! I've often wondered how hard it would be to make portable battery-powered clocks use 60 Hz noise as a timekeeping source. Maybe I should make a project out of it.
- deleted 2y ago
  [deleted]
- rrr_oh_man 2y ago
  > Typical crystal oscillators can gain or lose seconds per day. Are you sure? I only owned a quartz watch when I was a kid, but all sources I find on the web say even the lowest quality quartz watch movements are accurate to +- 20-30 seconds a month. For comparison: my several decades old manual Poljot loses some seconds per day.
  - AdamH12113 2y ago
    The Casio G-Shock I got in the 90s was ~66 ppm fast, which worked out to ~5 seconds/day. There are cheap crystals on Digi-Key with ~10 ppm accuracy, which is around 0.86 seconds/day. But crystals drift with age (and a tiny bit with temperature). Perhaps watches have improved since I last looked, but I would want to measure the actual real-world accuracy before believing anything better than 1 second/day.
  - crote 2y ago
    Yeah, that sounds about right. Crystal oscillators typically have an accuracy of about 20ppm, which is 1.73 seconds per day. Keep in mind that those number are a guaranteed worst-case performance - real-world performance is often much better.
- agos 2y ago
  how more expensive is a "more expensive" oscillator?
Taniwha 2y ago
There used to be a local hydro generation that fed the local city, they had 2 clocks on the wall, one on the local grid and one on the national one - some time late at night they'd speed up/slow down the local grid to keep the clocks in sync

pezezin 2y ago

A difference in frequency is not that big of a problem... except for the fact that you can't easily transfer power across the two grids. Japan has some power conversion stations, but when the Tohoku earthquake and tsunami of 2011 knocked off several powerplants in the 50 Hz half of the country (including Fukushima), they could not transfer enough power from the other side, and the suffered many blackouts, even though the 60 Hz half of the country had power to spare.

johannes1234321 2y ago
> A difference in frequency is not that big of a problem... except for the fact that you can't easily transfer power across the two grids. And for everything, which uses the frequency as a clock.
- pezezin 2y ago
  True. Nowadays it is not a problem, but it makes me wonder how they could make 60 Hz television run on a 50 Hz grid.
  - lxgr 2y ago
    I've been wondering that too recently, and apparently it wasn't that big of a deal [1] – more recent analog TVs weren't that susceptible to mains interference of the sort that benefited from being synchronized to the frame rate. In other words, the mains frequency was never used as a frequency source for TVs, and the apparent frequency match was only to make interference patterns not wander around the screen. [1] https://electronics.stackexchange.com/questions/164249/is-the-design-decision-for-different-frequencies-in-pal-and-ntsc-related-to-the https://electronics.stackexchange.com/questions/164249/is-th...

lxgr 2y ago

A motor running at 20% higher/16% lower speeds might break some things, I could imagine?

quickthrowman 2y ago
If the motor is designed for it, then no. Many motors these days are built to handle variable frequencies on account of VFDs A variable-frequency drive is a motor controller that adjusts the frequency of the power delivered to a motor to speed it up or slow it down. It could possibly damage a motor that isn’t designed for use with a VFD. https://en.m.wikipedia.org/wiki/Variable-frequency_drive https://en.m.wikipedia.org/wiki/Variable-frequency_drive