Anyone (ideally in the UK) got a spare rotary knob for the 5370B TI counter?
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 jn6wfo@gmail.com wrote:
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Chris Albertson
Redondo Beach, California
[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)" drkirkby@kirkbymicrowave.co.uk
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
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 eb4apl@gmail.com 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.
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.
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
On 1 Jan 2017 05:07, "Chris Albertson" albertson.chris@gmail.com 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
On 30 December 2016 at 23:58, Dr. David Kirkby - Kirkby Microwave Ltd <
drkirkby@kirkbymicrowave.co.uk> wrote:
I bought a 5370B TI counter which arrived today. It needs a bit of TLC,
but nothing too bad. But one of the rotary knobs is incomplete. Does anyone
have a spare knob? Contact me off list if you do.
It has been great to see the response of many people offering me a free
knob, or the knob for just the postage cost. But this is now resolved.
Robert Atkinson is kindly putting one for me in the post, so I have no need
for any other offers, but thank you anyone that did offer one. In the event
the one Robert sends is not suitable, I will contact the many other that
offered knobs.
It is great to see the generosity of people to help someone else. Not a
single person asked for any money except postage costs.
Dave