We were told last week that a temporary generator would be installed
because the substation next door needed some attention. It went in this
morning, and by late afternoon was having problems. The resulting
effects were interesting.

The newish Panasonic TV went off. After a few seconds it went on again,
then off, etc. I disconnected it from the mains. As far as I could tell,
everything else seemed OK. I turned on our elderly Roberts DAB radio,
and although it came on it wouldn't tune any station. It was then I
noticed the house lighting didn't seem its normal brightness. All the
lights - LED, compact fluorescents, and one tungsten (over the hob) were
working, but dimmer than usual. A couple of old T5 fluorescents would
not turn on when I tried them. NB - none of the lamps are dimmable.

A digital voltmeter showed the mains voltage was 160V. I turned on our
old Sharp 22" TV and it worked without problem. After a few minutes, the
Sharp went off. I checked the voltage; it was now 140V. Some of the LEDs
no longer worked. These were Wilko ones with a semicircular design of
light emitter (they no longer supply them, and I haven't been able to
find a picture on the internet). The other G9, COB-type design,
continued to work.

Then the remaining LED lighting went off. A quick check showed the mains
was now 80V. Amazingly, the compact fluorescents were still working. A
couple of other devices working off of wall warts still operated, but
that is not too surprising. I was going to investigate further, but the
power failed completely.

I find it extraordinary that the compact fluorescents stayed on at 80V.

--

Jeff

On 01/02/2021 22:31, Jeff Layman wrote:
We were told last week that a temporary generator would be installed
because the substation next door needed some attention. It went in this
morning, and by late afternoon was having problems. The resulting
effects were interesting.

The newish Panasonic TV went off. After a few seconds it went on again,
then off, etc. I disconnected it from the mains. As far as I could tell,
everything else seemed OK. I turned on our elderly Roberts DAB radio,
and although it came on it wouldn't tune any station. It was then I
noticed the house lighting didn't seem its normal brightness. All the
lights - LED, compact fluorescents, and one tungsten (over the hob) were
working, but dimmer than usual. A couple of old T5 fluorescents would
not turn on when I tried them. NB - none of the lamps are dimmable.

A digital voltmeter showed the mains voltage was 160V. I turned on our
old Sharp 22" TV and it worked without problem. After a few minutes, the
Sharp went off. I checked the voltage; it was now 140V. Some of the LEDs
no longer worked. These were Wilko ones with a semicircular design of
light emitter (they no longer supply them, and I haven't been able to
find a picture on the internet). The other G9, COB-type design,
continued to work.

Then the remaining LED lighting went off. A quick check showed the mains
was now 80V. Amazingly, the compact fluorescents were still working. A
couple of other devices working off of wall warts still operated, but
that is not too surprising. I was going to investigate further, but the
power failed completely.

I find it extraordinary that the compact fluorescents stayed on at 80V.


The PSU for my laptop says it should work at 100v but if the voltage
dropped that low we might not be able to cook the dinner.


--
Michael Chare

On 01/02/2021 22:31, Jeff Layman wrote:
We were told last week that a temporary generator would be installed
because the substation next door needed some attention. It went in this
morning, and by late afternoon was having problems. The resulting
effects were interesting.

The newish Panasonic TV went off. After a few seconds it went on again,
then off, etc. I disconnected it from the mains. As far as I could tell,
everything else seemed OK. I turned on our elderly Roberts DAB radio,
and although it came on it wouldn't tune any station. It was then I
noticed the house lighting didn't seem its normal brightness. All the
lights - LED, compact fluorescents, and one tungsten (over the hob) were
working, but dimmer than usual. A couple of old T5 fluorescents would
not turn on when I tried them. NB - none of the lamps are dimmable.

A digital voltmeter showed the mains voltage was 160V. I turned on our
old Sharp 22" TV and it worked without problem. After a few minutes, the
Sharp went off. I checked the voltage; it was now 140V. Some of the LEDs
no longer worked. These were Wilko ones with a semicircular design of
light emitter (they no longer supply them, and I haven't been able to
find a picture on the internet). The other G9, COB-type design,
continued to work.

Then the remaining LED lighting went off. A quick check showed the mains
was now 80V. Amazingly, the compact fluorescents were still working. A
couple of other devices working off of wall warts still operated, but
that is not too surprising. I was going to investigate further, but the
power failed completely.

I find it extraordinary that the compact fluorescents stayed on at 80V.

We have a HV cable fault a couple of weeks back. It caused a power cut
for a couple of hours in the morning. Then came back when they "fixed"
it (turns out they just routed round it and stuck in some temporary
gennys - because it was underground and worse than they expected).

We then got another power cut a few hours later during the early
evening, while they actually fixed it. (had to cook dinner on the two
burner gas ring set I normally drag out to sit beside the BBQ!)

When they fixed it for real, and the power did come back it was clear
not all was well. The voltage was sat about 200V. Most things worked ok,
although lamps were dimmer - even LEDs. The most notable exception
(which drew my attention to the voltage) was the microwave turntable
motor sound "weaker", and there was pretty much no heating effect at all
for anything you put in the oven.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 02/02/2021 00:00, John Rumm wrote:

We have a HV cable fault a couple of weeks back. It caused a power cut
for a couple of hours in the morning. Then came back when they "fixed"
it (turns out they just routed round it and stuck in some temporary
gennys - because it was underground and worse than they expected).

We then got another power cut a few hours later during the early
evening, while they actually fixed it. (had to cook dinner on the two
burner gas ring set I normally drag out to sit beside the BBQ!)

When they fixed it for real, and the power did come back it was clear
not all was well. The voltage was sat about 200V. Most things worked
ok, although lamps were dimmer - even LEDs. The most notable exception
(which drew my attention to the voltage) was the microwave turntable
motor sound "weaker", and there was pretty much no heating effect at
all for anything you put in the oven.


I remember I was sat one summer evening watching the TV (this was 1998
ish, so a CRT telly). I thought, but wasn't sure that the scan
momentarily collapsed and restored.
Didn't think any more of it, but then a few mins later the phone/answer
phone that was powered by a wall wart started bleeping and clicking. The
LED call indicator was randomly flashing digits, and they were dim. I
pulled the connector out of the unit, and measured the DC volts from the
wall wart, it was only 4 or 5 volts (should have been 12 I think)
At that point the doorbell rang, it was my neighbour. She asked whether
I had any power. Well yes, I said, and went to switch on the hall light
to prove it. The bulb just gave a tiny glow.
All the pennies dropped at that point !Â* I hit the main breaker on the
CU, and then just energised the lighting circuit alone. Measured the
voltage, it was 80 volts.

The remarkable thing was the TV had been perfectly happy working at 80
volts. That's SMPSUs for you I suppose. I bet its mains flex was warm
though ?

I find it amazing that the company have a generator for 230v which actually
runs at such a low voltage without simply stopping.

Many devices these days are happy on very low voltages but they do not like
variable waveforms and instability of voltage over time.
Many go into self protection.

I'd have thought that a power company should understand about loads and
capacities of their generators and what will happen if lots of power is
taken off a single phase.
I mean sounds like a third world country story where the generator runs off
an old VW Beetles back wheel and a belt.
Brian

--

This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"Jeff Layman" wrote in message
...
We were told last week that a temporary generator would be installed
because the substation next door needed some attention. It went in this
morning, and by late afternoon was having problems. The resulting effects
were interesting.

The newish Panasonic TV went off. After a few seconds it went on again,
then off, etc. I disconnected it from the mains. As far as I could tell,
everything else seemed OK. I turned on our elderly Roberts DAB radio, and
although it came on it wouldn't tune any station. It was then I noticed
the house lighting didn't seem its normal brightness. All the lights -
LED, compact fluorescents, and one tungsten (over the hob) were working,
but dimmer than usual. A couple of old T5 fluorescents would not turn on
when I tried them. NB - none of the lamps are dimmable.

A digital voltmeter showed the mains voltage was 160V. I turned on our old
Sharp 22" TV and it worked without problem. After a few minutes, the Sharp
went off. I checked the voltage; it was now 140V. Some of the LEDs no
longer worked. These were Wilko ones with a semicircular design of light
emitter (they no longer supply them, and I haven't been able to find a
picture on the internet). The other G9, COB-type design, continued to
work.

Then the remaining LED lighting went off. A quick check showed the mains
was now 80V. Amazingly, the compact fluorescents were still working. A
couple of other devices working off of wall warts still operated, but that
is not too surprising. I was going to investigate further, but the power
failed completely.

I find it extraordinary that the compact fluorescents stayed on at 80V.

--

Jeff

"Brian Gaff (Sofa)" wrote in message
...
I find it amazing that the company have a generator for 230v which
actually runs at such a low voltage without simply stopping.

Many devices these days are happy on very low voltages but they do not
like variable waveforms and instability of voltage over time.
Many go into self protection.

I'd have thought that a power company should understand about loads and
capacities of their generators and what will happen if lots of power is
taken off a single phase.
I mean sounds like a third world country story where the generator runs
off an old VW Beetles back wheel and a belt.

A few years ago, the electricity company was doing a lot of work on its
overhead mains-distribution cabling in various villages - maybe they were
replacing four separate wires (three phases plus neutral) with a single
fatter cable. This meant that they planned to disconnect each village in
turn from the mains and install temporary diesel generators. The one that
served our group of 20 or so houses was within earshot of our house.

It was surprising how quickly I got used to the constant low-frequency
throbbing. However what was very noticeable was the *variation* in engine
note. I could actually hear the legendary "Coronation Street advert break
effect": at about the same time every evening, the engine note changed and
the engine sounded to be working harder. I put the telly on the following
evening and the change happened about 30 seconds after Coronation Street
went to a commercial break - presumably as everyone switched their kettles
on for a cuppa. I knew it happened and that power stations were geared up
for suddenly having to supply extra power according to surges in demand
during advert breaks, but I'd never witnessed it in action.

I'm not sure how good the frequency regulation was, but we were warned by
the electricity company that mains-powered clocks might not be as accurate
while our power was coming from the generators.

Where we live now, the mains voltage varies quite a bit. I've got an energy
monitoring plug and when I remember I look at it. The frequency is always
between about 49.8 Hz and 50.2, but the voltage varies between 227 V (the
lowest I've seen) and about 265.

On 02/02/2021 09:48, NY wrote:


I'm not sure how good the frequency regulation was, but we were warned
by the electricity company that mains-powered clocks might not be as
accurate while our power was coming from the generators.

Oh, it won't be. Our bit of our housing estate spent about 10 days on a
genny. The clocks gained about 90 seconds a day, after the first week
our two lads noticed they were arriving* early at school :-)

On 01/02/2021 22:31, Jeff Layman wrote:
We were told last week that a temporary generator would be installed
because the substation next door needed some attention. It went in this
morning, and by late afternoon was having problems. The resulting
effects were interesting.

The newish Panasonic TV went off. After a few seconds it went on again,
then off, etc. I disconnected it from the mains. As far as I could tell,
everything else seemed OK. I turned on our elderly Roberts DAB radio,
and although it came on it wouldn't tune any station. It was then I
noticed the house lighting didn't seem its normal brightness. All the
lights - LED, compact fluorescents, and one tungsten (over the hob) were
working, but dimmer than usual. A couple of old T5 fluorescents would
not turn on when I tried them. NB - none of the lamps are dimmable.

LED ones ought to be able to maintain most of their brightness.

Filament ones would be quite dim on such a low voltage and kettles take
an age to boil. We sometimes end up with about 200v if a single phase
(not ours) croaks and the village is left with 2 live phases and
neutral. I can tell if this happens by looking to see which emergency
lights come on in the village hall. My PC ploughs on quite happily.

A digital voltmeter showed the mains voltage was 160V. I turned on our
old Sharp 22" TV and it worked without problem. After a few minutes, the
Sharp went off. I checked the voltage; it was now 140V. Some of the LEDs
no longer worked. These were Wilko ones with a semicircular design of
light emitter (they no longer supply them, and I haven't been able to
find a picture on the internet). The other G9, COB-type design,
continued to work.

I'm surprised that a modern TV doesn't have a PSU good for 100-240vac.
It hardly costs them any more to do that as the main PSU expense is
mostly providing insulation good for 240 mains.

Then the remaining LED lighting went off. A quick check showed the mains
was now 80V. Amazingly, the compact fluorescents were still working. A
couple of other devices working off of wall warts still operated, but
that is not too surprising. I was going to investigate further, but the
power failed completely.

I find it extraordinary that the compact fluorescents stayed on at 80V.

Once the arc has struck the voltage needed to maintain a current flowing
through the plasma can be very low indeed.

They should have been able to maintain something nearer 210+v if the
generator had been properly sized for the job. Unless the fault is that
one mains phase is down and they are trying to fix it.

--
Regards,
Martin Brown

On 02/02/2021 08:43, Mark Carver wrote:
On 02/02/2021 00:00, John Rumm wrote:

We have a HV cable fault a couple of weeks back. It caused a power cut
for a couple of hours in the morning. Then came back when they "fixed"
it (turns out they just routed round it and stuck in some temporary
gennys - because it was underground and worse than they expected).

We then got another power cut a few hours later during the early
evening, while they actually fixed it. (had to cook dinner on the two
burner gas ring set I normally drag out to sit beside the BBQ!)

When they fixed it for real, and the power did come back it was clear
not all was well. The voltage was sat about 200V. Most things worked
ok, although lamps were dimmer - even LEDs. The most notable exception
(which drew my attention to the voltage) was the microwave turntable
motor sound "weaker", and there was pretty much no heating effect at
all for anything you put in the oven.


I remember I was sat one summer evening watching the TV (this was 1998
ish, so a CRT telly). I thought, but wasn't sure that the scan
momentarily collapsed and restored.
Didn't think any more of it, but then a few mins later the phone/answer
phone that was powered by a wall wart started bleeping and clicking. The
LED call indicator was randomly flashing digits, and they were dim. I
pulled the connector out of the unit, and measured the DC volts from the
wall wart, it was only 4 or 5 volts (should have been 12 I think)
At that point the doorbell rang, it was my neighbour. She asked whether
I had any power. Well yes, I said, and went to switch on the hall light
to prove it. The bulb just gave a tiny glow.
All the pennies dropped at that point !Â* I hit the main breaker on the
CU, and then just energised the lighting circuit alone. Measured the
voltage, it was 80 volts.

The remarkable thing was the TV had been perfectly happy working at 80
volts. That's SMPSUs for you I suppose. I bet its mains flex was warm
though ?

Yup SMPSUs will quite often have a wide operating voltage range.

With a SMPSU they typically draw current only for a short section of the
mains input waveform. So with a lower voltage it would draw less peak
current, but for a larger proportion of each mains cycle. So the average
power would remain much the same...

Some induction motors can be harmed by low voltage though - since it
will draw more current when under load at lower voltage, and so will get
hotter. You might exceed the maximum current rating for the windings.
You also lose starting torque - so there is a chance of stalling it at
startup. So fridges / freezers are probably the most likely things to
get killed by low voltage in a domestic environment.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

Jeff Layman wrote in news:rv9vgu$q0s$1@dont-
email.me:

We were told last week that a temporary generator would be installed
because the substation next door needed some attention. It went in this
morning, and by late afternoon was having problems. The resulting
effects were interesting.


A digital voltmeter showed the mains voltage was 160V.

If this is still the case then I'd have an urgent word with them about the
out of spec undervoltage.

Fridges and freezers are particularly susceptible to undervoltage leading
the compressor to stall and burn out in short order.

In the developing world where brownouts are not uncommon it's common to
connect voltage monitor ahead of these items to disconect low voltages
automatically and only reconnect when the voltage recovers fully.

On 02/02/2021 08:46, Brian Gaff (Sofa) wrote:

I find it amazing that the company have a generator for 230v which actually
runs at such a low voltage without simply stopping.

The voltage drop may not be at the generator itself - it might just be
injecting power at a different location that makes the voltage drop
where it reaches your property more noticeable.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 02/02/2021 11:19, John Rumm wrote:
On 02/02/2021 08:46, Brian Gaff (Sofa) wrote:

I find it amazing that the company have a generator for 230v which
actually
runs at such a low voltage without simply stopping.

The voltage drop may not be at the generator itself - it might just be
injecting power at a different location that makes the voltage drop
where it reaches your property more noticeable.

To be that far out it must be either vastly overloaded or not driving
all three phases. Worst I have seen on a generator set is about 210v.

The default assumption on UK mains supply three phase wiring is that the
loads on all three phases are approximately in balance.

--
Regards,
Martin Brown

In article ,
John Rumm wrote:
On 02/02/2021 08:46, Brian Gaff (Sofa) wrote:

I find it amazing that the company have a generator for 230v which
actually runs at such a low voltage without simply stopping.

The voltage drop may not be at the generator itself - it might just be
injecting power at a different location that makes the voltage drop
where it reaches your property more noticeable.

when we had a local under road cable fault - we had a genny to ourselves.
Mind you it was installed at about 2am, failure had been about 1pm. But,
the stuff in the freezer was fine. We had the genny for 4 days.

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

On 01/02/2021 22:31, Jeff Layman wrote:
We were told last week that a temporary generator would be installed
because the substation next door needed some attention. It went in this
morning, and by late afternoon was having problems. The resulting
effects were interesting.

The newish Panasonic TV went off. After a few seconds it went on again,
then off, etc. I disconnected it from the mains. As far as I could tell,
everything else seemed OK.

Mine did that every time I tried to use its Ethernet interface. I took
it back and got it replaced. Its a feature of those beasts. Dont like
low voltage AT ALL


I turned on our elderly Roberts DAB radio,
and although it came on it wouldn't tune any station. It was then I
noticed the house lighting didn't seem its normal brightness. All the
lights - LED, compact fluorescents, and one tungsten (over the hob) were
working, but dimmer than usual. A couple of old T5 fluorescents would
not turn on when I tried them. NB - none of the lamps are dimmable.

A digital voltmeter showed the mains voltage was 160V. I turned on our
old Sharp 22" TV and it worked without problem. After a few minutes, the
Sharp went off. I checked the voltage; it was now 140V. Some of the LEDs
no longer worked. These were Wilko ones with a semicircular design of
light emitter (they no longer supply them, and I haven't been able to
find a picture on the internet). The other G9, COB-type design,
continued to work.

Then the remaining LED lighting went off. A quick check showed the mains
was now 80V. Amazingly, the compact fluorescents were still working. A
couple of other devices working off of wall warts still operated, but
that is not too surprising. I was going to investigate further, but the
power failed completely.

I find it extraordinary that the compact fluorescents stayed on at 80V.



--
"And if the blind lead the blind, both shall fall into the ditch".

Gospel of St. Mathew 15:14

On 01/02/2021 23:30, Michael Chare wrote:


The PSU for my laptop says it should work at 100v but if the voltage
dropped that low we might not be able to cook the dinner.


I worked once on a scope design that was happy from 36V DC (what an
aircraft raising its undercarriage drops to) to 250VAC. all on the same
PSU with no taps changed.

It can be done if people want to do it, but the grid is usually much
more stable than that so why bother?


--
€œThe ultimate result of shielding men from the effects of folly is to
fill the world with fools.€�

Herbert Spencer

On 02/02/2021 11:41, charles wrote:
In article ,
John Rumm wrote:
On 02/02/2021 08:46, Brian Gaff (Sofa) wrote:

I find it amazing that the company have a generator for 230v which
actually runs at such a low voltage without simply stopping.

The voltage drop may not be at the generator itself - it might just be
injecting power at a different location that makes the voltage drop
where it reaches your property more noticeable.

when we had a local under road cable fault - we had a genny to ourselves.
Mind you it was installed at about 2am, failure had been about 1pm. But,
the stuff in the freezer was fine. We had the genny for 4 days.

When they cut the 11KV ring to get it from over my house to under the
road, two of us had a genny for a week.

Not very stable. Things tripped. But the microwave didn't dim the lights
as much as the pole mounted transformer had done!

When they finished I had my own personal substation. That didn't dim at ALL.


--
Outside of a dog, a book is a man's best friend. Inside of a dog it's
too dark to read.

Groucho Marx

On 02/02/2021 10:41, Martin Brown wrote:
On 01/02/2021 22:31, Jeff Layman wrote:
We were told last week that a temporary generator would be installed
because the substation next door needed some attention. It went in this
morning, and by late afternoon was having problems. The resulting
effects were interesting.

The newish Panasonic TV went off. After a few seconds it went on again,
then off, etc. I disconnected it from the mains. As far as I could tell,
everything else seemed OK. I turned on our elderly Roberts DAB radio,
and although it came on it wouldn't tune any station. It was then I
noticed the house lighting didn't seem its normal brightness. All the
lights - LED, compact fluorescents, and one tungsten (over the hob) were
working, but dimmer than usual. A couple of old T5 fluorescents would
not turn on when I tried them. NB - none of the lamps are dimmable.

LED ones ought to be able to maintain most of their brightness.

Filament ones would be quite dim on such a low voltage and kettles take
an age to boil. We sometimes end up with about 200v if a single phase
(not ours) croaks and the village is left with 2 live phases and
neutral. I can tell if this happens by looking to see which emergency
lights come on in the village hall. My PC ploughs on quite happily.

A digital voltmeter showed the mains voltage was 160V. I turned on our
old Sharp 22" TV and it worked without problem. After a few minutes, the
Sharp went off. I checked the voltage; it was now 140V. Some of the LEDs
no longer worked. These were Wilko ones with a semicircular design of
light emitter (they no longer supply them, and I haven't been able to
find a picture on the internet). The other G9, COB-type design,
continued to work.

I'm surprised that a modern TV doesn't have a PSU good for 100-240vac.
It hardly costs them any more to do that as the main PSU expense is
mostly providing insulation good for 240 mains.

I would tend to agree. However, both the Panasonic (58") and the Sharp
(22") are specced at 220 - 240V. Why the Sharp worked ok at 160 and the
Panny didn't suggests that Sharp may have been designed for perhaps 150
- 240V, but the Panny wasn't. Perhaps pennies count; the average power
consumption is no longer stated in the manual, but I guess it is around
120W. In that case, the "front end" of the SMPS would need diodes, and
maybe other components, rated at 0.5A. For the 115V equivalent, they
would need to be rated at 1A. Perhaps the bean counters specify 0.5A
components for TVs destined for Europe, and 1A components for the USA
and other 115V markets if the 230V ones are cheaper. I would have
thought that a single-specced 115 - 240V SMPS would be cheaper in
quantity than two 100 - 120V and 220 - 240V supplies, but maybe not.

Then the remaining LED lighting went off. A quick check showed the mains
was now 80V. Amazingly, the compact fluorescents were still working. A
couple of other devices working off of wall warts still operated, but
that is not too surprising. I was going to investigate further, but the
power failed completely.

I find it extraordinary that the compact fluorescents stayed on at 80V.

Once the arc has struck the voltage needed to maintain a current flowing
through the plasma can be very low indeed.

Yes, but 80V seems extremely low; the lights didn't even flicker.

They should have been able to maintain something nearer 210+v if the
generator had been properly sized for the job. Unless the fault is that
one mains phase is down and they are trying to fix it.

I don't know. The generator size looks to be about 300kVA. I guess that
would only do a single phase for our 250-dwelling village. According to
the guy I spoke to at SSE (he installed the generator), when the power
went off completely he said it was probably a main fuse failing further
back down the line. I later heard that it wasn't just our village, but
around 2000 homes within a mile or so who had no power. It seems too
much of a coincidence that the outage occurred while the temporary
generator was running, as the power here is very stable - we haven't had
an outage in years.

--

Jeff

On 02/02/2021 11:15, Peter Burke wrote:
Jeff Layman wrote in news:rv9vgu$q0s$1@dont-
email.me:

We were told last week that a temporary generator would be installed
because the substation next door needed some attention. It went in this
morning, and by late afternoon was having problems. The resulting
effects were interesting.


A digital voltmeter showed the mains voltage was 160V.

If this is still the case then I'd have an urgent word with them about the
out of spec undervoltage.

Fridges and freezers are particularly susceptible to undervoltage leading
the compressor to stall and burn out in short order.

In the developing world where brownouts are not uncommon it's common to
connect voltage monitor ahead of these items to disconect low voltages
automatically and only reconnect when the voltage recovers fully.

The low voltage was around for about half an hour or so, when the power
finally failed. It came back on a couple of hours later, when it was 242V.

--

Jeff

On 02/02/2021 11:46, The Natural Philosopher wrote:
On 01/02/2021 23:30, Michael Chare wrote:


The PSU for my laptop says it should work at 100v but if the voltage
dropped that low we might not be able to cook the dinner.


I worked once on a scope design that was happy from 36V DC (what an
aircraft raising its undercarriage drops to) to 250VAC. all on the same
PSU with no taps changed.

It can be done if people want to do it, but the grid is usually much
more stable than that so why bother?



Might need to in future ...

https://www.zerohedge.com/energy/eur...wables-problem

On 01/02/2021 22:31, Jeff Layman wrote:
We were told last week that a temporary generator would be installed
because the substation next door needed some attention. It went in this
morning, and by late afternoon was having problems. The resulting
effects were interesting.

The newish Panasonic TV went off. After a few seconds it went on again,
then off, etc. I disconnected it from the mains. As far as I could tell,
everything else seemed OK. I turned on our elderly Roberts DAB radio,
and although it came on it wouldn't tune any station. It was then I
noticed the house lighting didn't seem its normal brightness. All the
lights - LED, compact fluorescents, and one tungsten (over the hob) were
working, but dimmer than usual. A couple of old T5 fluorescents would
not turn on when I tried them. NB - none of the lamps are dimmable.

A digital voltmeter showed the mains voltage was 160V. I turned on our
old Sharp 22" TV and it worked without problem. After a few minutes, the
Sharp went off. I checked the voltage; it was now 140V. Some of the LEDs
no longer worked. These were Wilko ones with a semicircular design of
light emitter (they no longer supply them, and I haven't been able to
find a picture on the internet). The other G9, COB-type design,
continued to work.

Then the remaining LED lighting went off. A quick check showed the mains
was now 80V. Amazingly, the compact fluorescents were still working. A
couple of other devices working off of wall warts still operated, but
that is not too surprising. I was going to investigate further, but the
power failed completely.

I find it extraordinary that the compact fluorescents stayed on at 80V.


John Rumm has summarised the situation very effectively:

1. Items including switched-mode power supplies work perfectly over a
wide range of supply voltage.

2. The dangerous aspect of supply voltage variation is motor stalling.

One of the problem nowadays is that so much of our stuff is SMPSU-based
that most householders are unaware of supply voltage variations.

In this part of Buckinghamshire, "brown-outs" are quite common - but I
seem to be the only one who calls out the cavalry.

And when I call the emergency line there is no-one who understands
John's second point.

PA

The Natural Philosopher wrote:

I worked once on a scope design that was happy from 36V DC (what an
aircraft raising its undercarriage drops to) to 250VAC. all on the same
PSU with no taps changed.

My rechargeable razor is ok from 12 Vdc to 240 Vac, which is
really handy when spending time in my touring caravan.

It is so useful, but no longer available, that when the battery
lost capacity, I soldered in a new one.

Chris
--
Chris J Dixon Nottingham UK
@ChrisJDixon1

Plant amazing Acers.

On 02/02/2021 14:28, Peter Able wrote:

2. The dangerous aspect of supply voltage variation is motor stalling.
Are they any 'insufficient voltage' breakers available to mitigate
against that problem ?

On 02/02/2021 09:48, NY wrote:
"Brian Gaff (Sofa)" wrote in message
...
I find it amazing that the company have a generator for 230v which
actually runs at such a low voltage without simply stopping.

Many devices these days are happy on very low voltages but they do not
like variable waveforms and instability of voltage over time.
Many go into self protection.

I'd have thought that a power company should understand about loads
and capacities of their generators and what will happen if lots of
power is taken off a single phase.
I mean sounds like a third world country story where the generator
runs off an old VW Beetles back wheel and a belt.

A few years ago, the electricity company was doing a lot of work on its
overhead mains-distribution cabling in various villages - maybe they
were replacing four separate wires (three phases plus neutral) with a
single fatter cable. This meant that they planned to disconnect each
village in turn from the mains and install temporary diesel generators.
The one that served our group of 20 or so houses was within earshot of
our house.

It was surprising how quickly I got used to the constant low-frequency
throbbing. However what was very noticeable was the *variation* in
engine note. I could actually hear the legendary "Coronation Street
advert break effect": at about the same time every evening, the engine
note changed and the engine sounded to be working harder. I put the
telly on the following evening and the change happened about 30 seconds
after Coronation Street went to a commercial break - presumably as
everyone switched their kettles on for a cuppa. I knew it happened and
that power stations were geared up for suddenly having to supply extra
power according to surges in demand during advert breaks, but I'd never
witnessed it in action.

I'm not sure how good the frequency regulation was, but we were warned
by the electricity company that mains-powered clocks might not be as
accurate while our power was coming from the generators.

Where we live now, the mains voltage varies quite a bit. I've got an
energy monitoring plug and when I remember I look at it. The frequency
is always between about 49.8 Hz and 50.2, but the voltage varies between
227 V (the lowest I've seen) and about 265.

You wouldn't see a frequqency outside 49.8 to 50.2 because national grid
will have taken emergency action, like an enforced powercut.

Lowest voltage I ever saw was 187V. I rang the EDF emergency number and
bloke who answered basically said "so what".
My ancient plugin wattmeter says 221V at the moment.

Mark Carver wrote in news:i7t68hF6atsU1
@mid.individual.net:

On 02/02/2021 14:28, Peter Able wrote:

2. The dangerous aspect of supply voltage variation is motor stalling.
Are they any 'insufficient voltage' breakers available to mitigate
against that problem ?

Undervoltage relay or Voltage Monitoring Relay seem to be the key phrases,
going rate about 40quid.

https://uk.farnell.com/c/switches-re...itoring-relays

On 02/02/2021 11:41, charles wrote:
In article ,
John Rumm wrote:
On 02/02/2021 08:46, Brian Gaff (Sofa) wrote:

I find it amazing that the company have a generator for 230v which
actually runs at such a low voltage without simply stopping.

The voltage drop may not be at the generator itself - it might just be
injecting power at a different location that makes the voltage drop
where it reaches your property more noticeable.

when we had a local under road cable fault - we had a genny to ourselves.
Mind you it was installed at about 2am, failure had been about 1pm. But,
the stuff in the freezer was fine. We had the genny for 4 days.

Yeah we had one shared with about a dozen properties for a few days some
time ago when they replaced all the overhead LV wiring with ABCs.
Voltage and stability were ok, but it did conk out a couple of times.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 02/02/2021 11:19, John Rumm wrote:
On 02/02/2021 08:46, Brian Gaff (Sofa) wrote:

I find it amazing that the company have a generator for 230v which
actually
runs at such a low voltage without simply stopping.

The voltage drop may not be at the generator itself - it might just be
injecting power at a different location that makes the voltage drop
where it reaches your property more noticeable.



Lucky to get a generator at all !

In this impoverished neighbourhood, when a phase goes down, they
back-feed it from the nearest other sub's phase. The resulting line
length and phase imbalance always ensures a lively situation.

Once, this was the "solution" in use for over a month!

Time for some electrical - as well as political - levelling up, I
reckon.

PA

Andrew wrote:

Lowest voltage I ever saw was 187V. I rang the EDF emergency number and
bloke who answered basically said "so what".

Didn't you quote ESQR 27 (3) (b) to him?

https://www.legislation.gov.uk/uksi/2002/2665/regulation/27/made#regulation-27-3-b

"The Natural Philosopher" wrote in message
...
On 02/02/2021 11:41, charles wrote:
In article ,
John Rumm wrote:
On 02/02/2021 08:46, Brian Gaff (Sofa) wrote:

I find it amazing that the company have a generator for 230v which
actually runs at such a low voltage without simply stopping.

The voltage drop may not be at the generator itself - it might just be
injecting power at a different location that makes the voltage drop
where it reaches your property more noticeable.

when we had a local under road cable fault - we had a genny to ourselves.
Mind you it was installed at about 2am, failure had been about 1pm. But,
the stuff in the freezer was fine. We had the genny for 4 days.

When they cut the 11KV ring to get it from over my house to under the
road, two of us had a genny for a week.

Not very stable. Things tripped. But the microwave didn't dim the lights
as much as the pole mounted transformer had done!

When they finished I had my own personal substation.

Nope, just a transformer.

That didn't dim at ALL.

On Thu, 4 Feb 2021 06:41:36 +1100, Fred, better known as cantankerous
trolling senile geezer Rodent Speed, wrote:

FLUSH senile asshole's troll**** unread

--
Norman Wells addressing trolling senile Rodent:
"Ah, the voice of scum speaks."
MID:

Mark Carver wrote
Peter Able wrote

2. The dangerous aspect of supply voltage variation is motor stalling.

Are they any 'insufficient voltage' breakers
available to mitigate against that problem ?

Yep. common in the third world.

On Thu, 4 Feb 2021 09:49:08 +1100, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:

FLUSH the trolling senile asshole's latest troll**** unread


--
"Who or What is Rod Speed?

Rod Speed is an entirely modern phenomenon. Essentially, Rod Speed
is an insecure and worthless individual who has discovered he can
enhance his own self-esteem in his own eyes by playing "the big, hard
man" on the InterNet."
https://www.pcreview.co.uk/threads/r...d-faq.2973853/