Hi Frank and all,

I have 'heard' that in some countries (but not in the UK)
electro-mechanical kiloWattHour meters can rotate reversed when fed
I have never seen a reversible mechanical kWh meter and also never heared of
this, except running reverse due to incorrect wiring.

In our current home (IJmuiden, NL) we have an electronic 3-phase meter with
two counters for peak and off-peak. This meter also has a T3 to measure
energy supplied back into the net, though that requires a special contract.
It's a single LCD showing the counters sequentially.
I know the previously used electro mechanical meter in this house was
switched by a 230Vac signal on an extra wire in the mains cable. I'm prety
sure there are two 1.5 or 2.5 qmm wires with the four 6 or maybe 4 qmm wires
in the cable.
There still is an old boiler relay on the meter board controlled from the
same signal.
The new electronic meter might be frequency controlled.

In the previous home we did have an electro mechanical two-tarif meter and I
think that one was switched from an electronic unit that I presume was a
frequency selective relay.

The meter back in Newbury was just the standard single phase, single counter
type.


I would expect that all modern wind turbines use rectifiers direct on the
generator and then have DC power fed to one or more inverters in the base of
the mast.
The inverters are synchronised to the grid before switching the generator on
the net.
This is as I remember from college and as I read in the technical
description of the wind turbine on which PI3WAD is installed.


Angela
M1SCH / PE1BIV