OT: Smart meters...not very!

[The Natural Philosopher]

Oh dear, how sad, never mind.

[Harry Bloomfield]

It happens that The Natural Philosopher formulated :

I wonder why they mentioned 3ph right at the beginning of that, then swapped midway to domestic supplies which were presumably single phase?

I have tested both of my meters just as thoroughly as possible and found no obvious calibration errors. The rest of the Smart is sadly lacking.

[tim...]

I don't understand why the measuring part of the meter isn't exactly the same as the previous style of digital meter, like wot I have on my property right now

or perhaps these read wrongly as well

tim

[Caecilius]

This seems to be talking about a difference between "electomechanical" meters (presumably spinny disk ones) and "electronic" meters (presumably flashing light ones).

Electronic meters have been around for a long time now, and are not "smart meters".

[Harry Bloomfield]

tim... pretended :

No meter can measure equally accurately in all conditions, so all will read wrong to some extent, which is why they allow a tolerance of accuracy. They are suggesting these all electronic Smart Meters can miss the sudden surges in demand, I would suggest the older mechanical meters missed even more.

[Harry Bloomfield]

It happens that Caecilius formulated :

My SM's include the flashing lights. Yes the electronics one have been around for at least 20 years.

[Caecilius]

IIRC, the disks on the old mechanical meters would rotate even under no load until they reached a certain part of the disk and stopped. So I guess even a mometary draw would cause one revolution.

[The Natural Philosopher]

No. I dont think so at all.

[Tim+]

With no load where does the power come to drive the disk around?

Tim

[Harry Bloomfield]

Caecilius has brought this to us :

I have never seen that and I would doubt it.

[The Natural Philosopher]

Me neither. They stop where they were last seeing current flow.

[Caecilius]

[Harry Bloomfield]

Caecilius brought next idea :

My understanding is that both voltage and current coils need to be active, for the disc to rotate. Only one coil active, means the disc will be effectively braked.

[Harry Bloomfield]

Caecilius submitted this idea :

Reading up a bit on this subject, there is a meter fault known as creep, where the meter will continue to turn slowly, despite no load. That is not the same as the disc doing a full revolution or completing a revolution, after demand has ended.

[harry]

No. As an apprentice I worked in the YEB repair /recalibrate shop for meters

[harry]

There was permanent magnet to stop this sort of thing which was caused by the meter working as an induction motor due to the voltage coil.

The magnet also acted as a brake stopping the disk almost immediately when the current went off.

This gave rise to the urban myth that putting a magnet on top of the meter slowed it down.

[Tim Watts]

No they didn't - and there is no reason in physics that it should.

[Tim Watts]

Which has no effect unless there is another field to react against, from the current coil.

Think about it: Which way would a single coil drive the disk? And why?

[Andy Burns]

The paper also stated

"The study was carried out in a laboratory setting. If you looked at ones in homes I don't expect they would be 500 or 600 per cent out."

Maybe their tests used waveforms with more extreme power factors than household LED dimmers? It would be interesting to see how inaccurate the lab could force an analogue meter to read under the same conditions.

The UK certification for the type of meters likely to be found in a domestic installation requires accuracy +/- 1.9% but only tests at power factors of 1.0 for a resistive load and 0.5 for an inductive load, with a deviation of 5% from sinusoidal current and voltage.

The chief executive of Green Energy UK demonstrated his lack of understanding when he said "Smart meters are essentially a 'second check' as energy suppliers keep a record of energy consumption".

I suspect he meant the in-house display of pounds and pence is only an estimate, not the amount that will be billed, as clearly there's nothing

*other* than the smart meter taking readings.

[Tim Watts]

Thick company executive demonstrates he has no clue about anything his company does.

In other news, Pope accused of being Catholic.