Power utilities tweak the system frequency on a daily basis to keep MAINS powered clocks correct. I wonder what their correction strategy was for the leap second?
On Tue, Jan 3, 2017 at 11:05 AM, Vlad <[email protected]> wrote: > > > Speaking about MAIN... I was interesting to see if "leap second" event has > correlation with MAIN frequency fluctuation > > Here is graphs for the MAIN periods recorded. Note: The data on the charts > is "smoothed" by Bezier curves > > I could see some "surge" which starts to climb in December 30 and end at > Dec 31 at the time close to the "leap second" event. But not sharp. > > For 16-12-29 00:00 to 17-01-02 00:00 > http://www.patoka.ca/OCXO/60hz-periods-Dec29-Jan2.png > > > For Dec 31: > http://www.patoka.ca/OCXO/60hz-periods-Dec31.png > > > It will be interesting to see/compare if anybody else has similar stats. > > Regards, > Vlad > > > On 2017-01-02 13:00, Tim Shoppa wrote: > >> What modern loads are actually sensitive to high (say, +10 to +20%) line >> voltage? >> >> Old incandescent light bulbs were among the most sensitive loads in the >> past (so much so, that 130V light bulbs were commonly available from the >> industrial suppliers). >> >> I would naively expect the modern CFL's and LED replacements to be fine >> with higher line voltage because they have their own built-in switching >> regulation. >> >> A lot of modern electronic equipment with switching supplies, are just >> fine >> at +20% line voltage and may even run cooler. >> >> Tim N3QE >> >> On Sun, Jan 1, 2017 at 11:49 PM, Bill Byrom <[email protected]> wrote: >> >> There are a couple of recent threads concerning the power line mains >>> voltage standards. After a bit of research and thinking, I have found >>> that this is a complex topic. The simple answer is: >>> >>> >>> * The standard in the US for the past 50 years has been 120/240 V +/- 5% >>> RMS at the service entrance to the building. This is a range of >>> 114/228 V to 126/252 V. >>> * The load voltage could be as low as 110/220 V and as high as 125/250 V >>> and be within specifications. >>> >>> >>> There are two voltage measurement points to consider: >>> >>> (1) Service voltage: This is the RMS voltage measured at the service >>> entrance to the building (at the metering point). >>> (2) Utilization voltage: This is the RMS voltage measured at the load. >>> It might be measured at an unused socket in a power strip feeding >>> several pieces of electronic equipment, for example. There are of >>> course many different utilization voltages present in a home or >>> business, depending on where you make the measurement. >>> >>> >>> Most US homes and small businesses are powered by what is commonly >>> called a "split-phase" 240 V feed. The final distribution system >>> transformer has a 240 V center-tapped secondary. The center tap is >>> grounded, and three wires are fed to the building (actually it might be >>> up to around 6 houses): >>> (1) Leg L1 or phase A (red wire) -- This wire will measure 120 V to the >>> neutral or 240 V to Leg L2. >>> (2) Neutral (white wire) -- This wire is grounded at the distribution >>> system and at the service entrance to the building. >>> (3) Leg L2 phase B (black wire) -- This wire will measure 120 V to the >>> neutral or 240 V to Leg L1. >>> >>> >>> Large appliances and HVAC systems are usually connected across L1-L2 >>> (240 V), while most sockets are on circuits either connected across L1- >>> neutral (120 V) or L2-neutral (120 V). >>> >>> >>> The voltages I have described are the current standardized values for >>> the service voltage which have been in general use for about 50 years >>> (120/240 V +/- 5%). I believe that the original systems installed before >>> 1940 were designed for a 110/220 V nominal service voltage, but after a >>> report in 1949 the nominal service voltage was increased to 117/234 V, >>> as specified in ANSI C84.1-1954. After research in actual buildings, in >>> the 1960's the nominal service voltage was increased again, to 120/240 V >>> in the ANSI C84.1-1970 standard. The purpose is to keep the utilization >>> voltage at the load above 110/220 V. >>> >>> >>> The voltage at the service entrance should in most cases be in Range A >>> (120/240V +/-5%). On each 120V leg the service voltage should therefore >>> be between 114 and 126 V. The utilization voltage at the load should be >>> between 110 and 125 V due to losses in building wiring. >>> >>> >>> See details of the current specifications at: >>> >>> http://www.pge.com/includes/docs/pdfs/mybusiness/ >>> customerservice/energystatus/powerquality/voltage_tolerance.pdf >>> >>> >>> These voltage specifications were designed for resistive loads and >>> measurement of the true RMS voltage. In most electronic equipment built >>> over the past 50 years, the power supply input circuitry is basically a >>> rectifier connected to a smoothing capacitor. This leads to high input >>> current surges during the peaks of the waveform, so that the peak >>> voltage is reduced much more by the building wiring resistance than if >>> the load was resistive for the same power consumption. >>> >>> >>> So the waveform shape at different utilization locations in a building >>> (with active equipment loads) may be different, so the voltage measured >>> by different AC measuring instruments can differ. Many meters are full >>> wave average measuring but calibrated so they only read RMS voltage >>> correctly on pure sinewaves. Other meters are true RMS measuring and >>> will read very close the correct RMS voltage even if the waveform is >>> distorted. >>> -- >>> >>> Bill Byrom N5BB >>> >>> >>> >>> >>> >>> On Sun, Jan 1, 2017, at 12:16 PM, CIW308 VE6OH wrote: >>> >>> > Mark, >>> >>> > >>> >>> > CSA have standards for over and under voltage, Typical no more that 3% >>> > over and 5% under if memory serves me. >>> >>> > >>> >>> > This might help ( >>> >>> > http://www.safetyauthority.ca/sites/default/files/csa- >>> fia3660-voltagedropcalc.pdf >>> > ) >>> >>> > The power companies here in Alberta are generally good about fixing >>> >>> > problems with line regulation. >>> >>> > There can be problems with industrial areas and big welders or motors >>> > staring as I am sure you know. >>> >>> > I am sure they do not want the bill for replacing equipment that was >>> >>> > subjected to over voltage. >>> >>> > >>> >>> > On UPSs: I am sure you are aware that may of them are not TRUE >>> > sine wave >>> > so the DMM may not read correctly. >>> >>> > >>> >>> > Mitch >>> >>> >>> _______________________________________________ >>> time-nuts mailing list -- [email protected] >>> To unsubscribe, go to https://www.febo.com/cgi-bin/ >>> mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >>> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to https://www.febo.com/cgi-bin/m >> ailman/listinfo/time-nuts >> and follow the instructions there. >> > > -- > WBW, > > V.P. > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/m > ailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
