British Gas - Smart meter bullying tactics

[Harry Bloomfield Esq]

Too late, that is already the case, with cheaper tariffs offered if willing to have one.

[charles]

as did ours.

[The Natural Philosopher]

Once upon a time. Not since Blair.

[Adam Funk]

What do they do about domestic appliances with motors?

[David Wade]

By the way keeping a meter does not ensure a meter reader will visit...

Ofgem repealed the requirement to inspect every two years in 2016...

Dave

[Vir Campestris]

Who took 8 years to notice the fault.

Interesting assumption. Why do you think they are not the same people? After all when smart meter installation was beginning nobody else had any relevant experience.

Andy

[Theo]

Many of them are multi-frequency, for others you just buy one for the right frequency. All the local shops will have the right one, and for smaller items like microwaves you just don't take them across the 'line'. It's a bit like LHD v RHD cars, when you move you sell locally and buy another on the other side.

Theo (who noticed they have some quite interesting 100v woodworking tools, and they're probably ok fed with 110v 50Hz from a site transformer)

[alan_m]

For a microwave it probably doesn't matter. The turntable will just rotate faster or slower dependant on the frequency.

[The Natural Philosopher]

For most things it won't matter. Anything with a transformer or switched mode supply that operates on 50 will operate on 60. Only things that wont work are synchronous motors - clocks and a few other things.

[alan_m]

Although BG used to send out the letters with red text saying that they had to perform a "safety inspection" if your meter had not been read for a couple of years and the meter reader had not managed to find you in when they had called, or you had ignored their letters about making an appointment at their convenience, the resulting safety inspection was... The meter reader turning up, shining a torch on the meter, recording the value and leaving within 15 seconds of setting foot inside you property.

I doubt if the meter reader had any gas related qualification nor any test equipment*. In my case the gas meter was inside under the stairs and where a lot of junk was stored. The meter reader wouldn't have been able to see any modification to the pipes unless all of that was removed.

*When my neighbour reported a suspected gas leak the technician who came out also asked to check around my meter and in the area where next door suspected the leak (party wall). He spent a good 5 minutes with a gas analyser establishing that there was no problem in my property.

[Theo]

Would a 60Hz microwave being run at 50Hz cause issues with the magnetron?

Not sure if it would, but I note in this schematic:

's an R-C circuit, which might be affected if the frequency changes. I'm not sure if that's there just for noise suppression, though.

Theo

[Rod Speed]

But the reverse isnt true. Stuff with a transformer which is designed to work at 60Hz can be killed when used on 50Hz. We had a very expensive US made mass spectrometer which quite literally burst into flames when first used on 50 Hz even when switched to 240V correctly.

[NY]

I would have thought that it would have been the step-up transformer and its input wiring that burst into flames, because the impedance of the primary winding is less at 50 Hz than at 60 Hz (maybe because the magnetism of the transformer core saturates).

Would this also have allowed too much power to be fed to the mass spectrometer on the secondary side?

Switched-mode PSUs are wonderful: you can feed them either 50 Hz or 60 Hz, but more than that, you can feed them anything from about 90 V to

260 V without having to change a transformer tap.

That's a good range of adjustment on the mark-space ratio of the high-frequency, to accommodate such a wide range of input voltage. I remember a university project was to design and build (and test!) a SMPSU, and to test its regulation over a wide range of input voltages (provided with a good old Variac!) and a wide range of loads on the low voltage side. The only thing to be careful of: on no account must the switching wave fail, because this would leave the power transistor turned permanently on: there was a period of about 5 seconds' grace, during which there was a rustling sound like autumn leaves, followed by a very loud bang as the transistor exploded. Several teams of students did that, and ours even embedded itself in the ceiling and was still there the following year. After that, we were all issued with plastic safety goggles... I was rather proud that our design won the prize for best regulation and highest efficiency, partly because someone in our team worked out that a dropping resistor that was needed before the bridge rectifier could be replaced with a capacitor which had the same impedance at 50 Hz, so the losses in that resistor were avoided.

[The Natural Philosopher]

What step up transformer? You would get a bit of core saturation at 50hz, if the thing was designed on the cheap.

No

Project I worked on ran from 48V DC (aircraft power) to 240V 50hz.

[Rod Speed]

Not with the magnetron but can do with the transformer.

[Vir Campestris]

We've got one which was probably designed for this dual frequency stuff. On 60Hz it would probably rotate every 10 seconds, which is convenient when it has a 10 second short burst button. The jug handle would always be at the front.

But over here it rotates every 12 seconds, which means on anything other than whole minutes the jug handle is around the back somewhere.

Andy

[NY]

Apologies, I was the wrong way round. Step *down* transformer: machine wants

120 V, transformer is fed 240 V input.

What would be the effect of core saturation? Would it lead to excessive input current to the transformer (and hence maybe blown fuse or overheating) or would it lead to excessive output supply (eg nominal 120 V actually being much higher)?

[Rod Speed]

NY [e-mail] wrote

No, the transformer got so hot that the pitch melted and started dripping out.

The problem is that it saturates and gets much hotter.

No.

Yeah, but this was back in the late 60s when those weren't practical.

They still aren't with microwaves even now.

[Rod Speed]

The mass spec always has a transformer to produce the internal rails. It had separate primary windings so could be used on a 120V or 240V mains. That was typical of all those sorts of instruments in those days.

The problem was that the transformer was designed for 60Hz and not for 50Hz. They supplied the correct transformer after the original burst into flames.

The core gets much too hot.

No.

No.

Yes, but due to core saturation, not to excessive input current.

There was no step down transformer, just the normal transformer based power supply that was typical at that time and for quite a while after that.

Still seen in microwaves.

[Max Demian]

But what if the secondary is effectively a resistance, as would be the case with a valve radio?