Re: [time-nuts] Line Voltage [Was: Anyone (ideally in the UK) ...]

[Mark Spencer]

Hi:

A few quick comments.   

I've used a Variac for years at home to drop the line voltage for older 
equipment with linear power supplies that run hotter than I would like.   (My 
HP5370B's don't fall into that category for me but I can understand why this is 
an issue for some individuals.)

I've encountered situations where the line voltage has been deliberately 
lowered to entire buildings which has in turn caused issues for equipment I was 
responsible for. 

In dealing with line voltage issues in Canada I've found that readings from my 
handheld fluke DMM seem to be accepted at face value by the individuals I've 
been dealing with.   Data collected from UPS systems doesn't seem to be as well 
accepted.

Mark Spencer

> On Jan 1, 2017, at 4:14 AM, Dr. David Kirkby (Kirkby Microwave Ltd) 
>  wrote:
> 
>> On 1 Jan 2017 11:10, "Hal Murray"  wrote:
>> 
>> The nice thing about the APC units is that they are close to free if you
> are
>> already going to purchase a UPS.
>> 
>> I agree that something like the Dranetz 658 would be better, but a quick
> peek
>> at eBay shows prices far beyond what I'm willing to pay.
>> 
>>> What's the sample rate on your APC UPS?
>> 
>> I don't know what the internal sampling rate is.  The API is
>>  tell me the current voltage
>>  tell me the lowest voltage since the last time I asked
>>  tell me the highest voltage since the last time I asked
> 
> Em, not a lot. My handheld true RMS Tektronix can give me the average. (One
> assumes an average of RMS values).
> 
>> I have a hack that reads as fast as it can.  If nothing interesting has
>> happened, it adds a line to the log file every 5 minutes.
> 
> Again,  I think if attending presenting data for others,  one wants to
> avoid hacks like that. One can always post-proces to indicate the points of
> particular interest.
> My biggest problem is that it is not very practical to log data at the
> incoming point, which is just above my back door.  If I lived on my own,  I
> could set up equipment easily to do this. But sharing a house with a my
> wife and a large German Shepherd dog, it is not practical to do it with the
> equipment I have.
> 
> I think measuring voltage elsewhere would give someone more reason to
> question its accuracy.  In my case, measuring in my lab would almost
> certainly give a power supply voltage lower than that coming in.
> 
> Anyway,  short term I will use a variac to lower the voltage to test
> equipment with linear power supplies.  I am less concerned about equipment
> with switch mode supplies.
> 
> Dave.
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Re: [time-nuts] Line Voltage [Was: Anyone (ideally in the UK) ...]

[Dr. David Kirkby (Kirkby Microwave Ltd)]

On 1 Jan 2017 11:10, "Hal Murray"  wrote:
>
> The nice thing about the APC units is that they are close to free if you
are
> already going to purchase a UPS.
>
> I agree that something like the Dranetz 658 would be better, but a quick
peek
> at eBay shows prices far beyond what I'm willing to pay.
>
> > What's the sample rate on your APC UPS?
>
> I don't know what the internal sampling rate is.  The API is
>   tell me the current voltage
>   tell me the lowest voltage since the last time I asked
>   tell me the highest voltage since the last time I asked

Em, not a lot. My handheld true RMS Tektronix can give me the average. (One
assumes an average of RMS values).

> I have a hack that reads as fast as it can.  If nothing interesting has
> happened, it adds a line to the log file every 5 minutes.

Again,  I think if attending presenting data for others,  one wants to
avoid hacks like that. One can always post-proces to indicate the points of
particular interest.
My biggest problem is that it is not very practical to log data at the
incoming point, which is just above my back door.  If I lived on my own,  I
could set up equipment easily to do this. But sharing a house with a my
wife and a large German Shepherd dog, it is not practical to do it with the
equipment I have.

I think measuring voltage elsewhere would give someone more reason to
question its accuracy.  In my case, measuring in my lab would almost
certainly give a power supply voltage lower than that coming in.

Anyway,  short term I will use a variac to lower the voltage to test
equipment with linear power supplies.  I am less concerned about equipment
with switch mode supplies.

Dave.
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Re: [time-nuts] Line Voltage [Was: Anyone (ideally in the UK) ...]

[Hal Murray]

The nice thing about the APC units is that they are close to free if you are 
already going to purchase a UPS.

I agree that something like the Dranetz 658 would be better, but a quick peek 
at eBay shows prices far beyond what I'm willing to pay.

> What's the sample rate on your APC UPS?

I don't know what the internal sampling rate is.  The API is
  tell me the current voltage
  tell me the lowest voltage since the last time I asked
  tell me the highest voltage since the last time I asked

I think I decided it's an 8 bit ADC so the resolution is far from wonderful.  
(The step size on a couple of handy readings in 0.7 volts.  8 bits gives a 
full scale of 180 volts.))

I have a hack that reads as fast as it can.  If nothing interesting has 
happened, it adds a line to the log file every 5 minutes.  If the min or max 
voltage has change enough, it logs a line now.  That gives me reasonably 
accurate timing on short glitches without cluttering up the log file with 
noise.

-- 
These are my opinions.  I hate spam.



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Re: [time-nuts] Line Voltage [Was: Anyone (ideally in the UK) ...]

[Dr. David Kirkby (Kirkby Microwave Ltd)]

On 1 Jan 2017 05:07, "Chris Albertson"  wrote:
>
> Just a comment for anyone who wants to log line voltage v. time.   If
> you have an APC "Smart UPS" battery backup unit these will log voltage
> and frequency to a file.

If the information is for your own use only, that is probably fine.  But if
you intend challenging the electricity supply company over it, I would use
a laboratory multimeter with a valid calibration certificate. It will give
your measurements far more credibility than the data from a UPS.

I would suggest that a 5.5 digit laboratory multimeter with a current
certificate from Keysight would be better than an 8.5 digit 3458A that is
out of the calibration period by a day, despite the latter having lower
uncertainty.

The point where you measure the voltage is probably important too.
Obviously wire resistance in a ring main reduces the voltage, so there's
not much point reporting that the voltage is low unless measured at the
point of the incoming supply. I suspect that it is better to measure there
whatever ones cause  for complete is. Possibly a motor run internally could
act as a generator and push the supply above the incoming voltage.

I don't know what (if any) averaging should be done.  Does one sample every
cycle?  I would probably set my 3457A  to sample 10 power line cycles (200
ms) here in the UK.  I think collecting data every cycle would be a bit
excessive, but maybe not.  One can always post process the data later to do
some averaging.

What's the sample rate on your APC UPS?

Dave
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Re: [time-nuts] Line Voltage [Was: Anyone (ideally in the UK) ...]

[Ruslan Nabioullin]

On 01/01/2017 12:07 AM, Chris Albertson wrote:

Just a comment for anyone who wants to log line voltage v. time.   If
you have an APC "Smart UPS" battery backup unit these will log voltage
and frequency to a file.  The unit connects to a computer via USB (and
an AC power cable).


As a more professional alternative, I suggest installing a power quality 
analyzer, particularly the Dranetz 658, which can be had for a modest 
amount off eBay.  If I remember correctly it is from the late 80s era, 
but nevertheless is very feature-filled---modular (mainframe with cards 
for: 4 channels for v, V, i, I, and f [incl. harmonic distortion 
analysis to the 50th. harmonic]; environmental monitoring [T, RH, 
radiated RF, conducted RF]; etc.), physically robust (but not 
rackmountable, I believe), is networkable with another such unit and of 
course interfaceable with a server via RS-232, and has a human interface 
right on the unit (incl. an entire miniature keyboard, floppy drive for 
memory expansion, and even a built-in thermal printer!)  When I was 
doing research, I could not find any other power quality analyzer that 
is physically robust, not to mention cheap, and those IT environmental 
monitors were underwhelming (no modularity, no RF probing, etc.), so I 
opted for this model for monitoring home metrology and METI lab and 
datacenter conditions, incl. the solar generation subsystem.


-Ruslan
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Re: [time-nuts] Line Voltage [Was: Anyone (ideally in the UK) ...]

[Jeremy Nichols]

Another option is to belong to the FNET/GridEye group operated by the 
University of Tennessee (http://fnetpublic.utk.edu/index.html). They 
have placed frequency/voltage monitors all over the United States; they 
also list sites out side USA but I don't know if those are their 
devices. The monitors use GPS for time and location information and send 
the data over an ethernet link to your router and hence to U of Tenn via 
the Internet. If you look at the "Table Display" page in their web site, 
I am Unit #853 in the Western Interconnection.


Jeremy


On 12/31/2016 9:07 PM, Chris Albertson wrote:

Just a comment for anyone who wants to log line voltage v. time.   If
you have an APC "Smart UPS" battery backup unit these will log voltage
and frequency to a file.  The unit connects to a computer via USB (and
an AC power cable).

You can collect data over a wide area using these power supplies,
logging data can be pushed over a network.

I would not buy an UPS just to log power statistics but many people
already have these

So you might wonder what is the line voltage in your lab. If you have
computer "server" of some kind you might also have an UPS and then you
might already have logs of voltage and frequency going back for years.




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[time-nuts] Line Voltage [Was: Anyone (ideally in the UK) ...]

[Jeremy Nichols]

[Sorry for the blank post earlier—TVB reminded me posts have to be plain 
text. My post was sent from my new-to-me iPad, probably in HTML. Have to 
learn how to turn that off!]


I too am concerned about high power-line voltage harming my collection 
of new and old electronics. A couple years ago I spent a lot of time 
documenting the line voltage at our home in northern California. The 
utility was consistently in excess of their 125 VAC specification. It 
took weeks of data before I got them to bring a recorder to my home and 
make their own measurement; once that was done they bumped the voltage 
down a little. The frequency also wanders but averages out to 60 Hertz, 
more or less (not Time-Nuts quality).


Jeremy


On 12/31/2016 11:57 AM, Tom Miller wrote:


- Original Message - From: "Dr. David Kirkby (Kirkby Microwave 
Ltd)" 
To: "Discussion of precise time and frequency measurement" 


Sent: Saturday, December 31, 2016 11:01 AM
Subject: Re: [time-nuts] Anyone (ideally in the UK) got a spare rotary 
knob for the 5370B TI counter?




On 31 December 2016 at 13:03, EB4APL  wrote:


Hi,

I'm not totally sure about the limits, but I have read several times 
that
in the UK the nominal supply voltage is 230 V +10%/−6% to 
accommodate the
fact that most supplies are in fact still 240 V. The context was 
that a lot

of test equipment failed when operated at around 250 V and many input
capacitors (particularly the ones inside a know brand IEC socket - 
filter)

caught fire.

Wikipedia says that several areas in UK still have 250 V because this
value is withing the current limits.

I think that the governing document is British Standard BS 7697: 
Nominal

voltages for low voltage public electricity supply systems —
(Implementation of HD 472 S1).

Regards,

Ignacio, EB4APL




Hi,
I have just been on to the phone of a friend of mine who spent much 
of his

like working in the electricity generating industry. Working at both
Darlington (coal) and Bradwell (nuclear) power stations in the UK. Among
many other things he said

* He did not know the current specifications limits for certain, but he
said easy to check. (What you say - 230 -6%/+10% does seem to be 
quoted in

many places, but I guess I should check it out.)
* Supply voltage is likely to be highest about at 2-3 am in Summer
* Supply voltage is likely to be lowest on a cold Winter's afternoon.
* Voltages in use around the county include at the least 11, 22, 33, 66,
132, 275 and 400 kV.
* There's not much standardization of generator voltage - Bradwell 
nuclear

power station was 11.1 kV.
* There are taps on the 275 kV transformers to keep the 132 kV close 
to 132

kV
* There are 6 taps on the 11 kV transformers feeding my house to 
adjust the
voltage. Those can only be adjusted with the 11 kV off - they can't 
be done

with it online. Essentially this means to change the taps, an area would
need to be powered off.
* If voltage is out of spec, it should be possible to get something done
about it.
* The electricity board can install monitor equipment.
* Since I am right by the 11 kV transformer, and other places further 
away,

dropping the voltage at my place might put other places too low.

I think short-term I will put the auto transformer in line. I will 
monitor

the mains, and report it in the summer, when I'm told it is likely to go
higher.

It hit 250.04 V in the last hour or so, but I have not seen the magic
figure of 253 V.

I'll get my 3457A calibrated by Keysight, then look to measure this 
and if

appropriate make a formal request to have the voltage checked, and
hopefully the problems would occur during the time it was monitored.

Dave
___


There are some devices that benefit from the higher voltage. Motors 
usually run cooler and last longer due to the lower I2R losses.
Maybe just use a buck transformer in your lab for the (older) test 
equipment.






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Re: [time-nuts] Line Voltage [Was: Anyone (ideally in the UK) ...]

[Chris Albertson]

Just a comment for anyone who wants to log line voltage v. time.   If
you have an APC "Smart UPS" battery backup unit these will log voltage
and frequency to a file.  The unit connects to a computer via USB (and
an AC power cable).

You can collect data over a wide area using these power supplies,
logging data can be pushed over a network.

I would not buy an UPS just to log power statistics but many people
already have these

So you might wonder what is the line voltage in your lab. If you have
computer "server" of some kind you might also have an UPS and then you
might already have logs of voltage and frequency going back for years.

On Sat, Dec 31, 2016 at 6:14 PM, Jeremy Nichols  wrote:
>
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-- 

Chris Albertson
Redondo Beach, California
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[time-nuts] Line Voltage [Was: Anyone (ideally in the UK) ...]

[Jeremy Nichols]

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