[time-nuts] Line Voltage - USA

Tue Jan 3 16:41:49 UTC 2017

Vlad

do you have that data for a longer period of time...say 3 to 6 months?

Dave

On 1/3/2017 11:05 AM, Vlad 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 <time at radio.sent.com> 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
>>>
>>>
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-- 
Dave
Manuals at ArtekManuals.com
www.ArtekManuals.com

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