No problem with a different circuit, but more so if you want to
connect to the supply. In fact people with wind etc. generators can
get permission to sell "green" electricity back to the grid
(automatic metering). It would be somehow satisfying buying night
time electricity from the suppliers and sell it back to them at a
profit.

How is that arranged? I presume the windmills produce DC?

Or if AC how do they arrange synchronisation with the
mains?
===============================
Domestic wind energy systems in the 1-10 kW range often involve an AC
generator ,its output being rectified with the DC fed into an inverter
which is synchronised with the grid.

In the UK a company 'Windsave' sells and (obligatory) installs 1 kW wind
generators which are connected to the domestic 230V-50 Hz system .
The location of the windgen and its nearby inverter cannot be too far
away from the switchboard (up to 15 metres). Apparently the output
voltage of the inverter is slightly higher than the grid supply , such
there is a preferential pick-off from the wind gen system.
However when no power is consumed wind generated energy is fed into the
grid.
I have 'heard' that in some countries (but not in the UK)
electro-mechanical kiloWattHour meters can rotate reversed when fed
with power from the consumer's side, with the counter counting down .
This would be very beneficial for people with the above described system
.. Perhaps someone on this NG can confirm that these meters really exist
and in which countries.

For my AR operations + desk lighting and peripherals I use 12 V
batteries charged by an up to 170 Watts windgen and 2 solar panels with
a total capacity of 128 Watts(peak)............just for the h*ll of it.
The wind gen. has a 3 phase generator and integral rectifying diodes( in
fact 2 bridge rectifiers of which 1 is fully utilised and the other one
only half )

Frank GM0CSZ / KN6WH The future is 'renewable'

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