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Mechanical generators will produce
true sine wave power. Most electronic
power inverters produce modified sine
wave power that approximates a sine
wave. There are more expensive electronic inverters that will produce “true”
sine wave power. Consider that grid-tie
inverters are capable of back-feeding the
grid in order to sell electricity back to
the power company — this requires very
close tolerances in both sine wave quality, as well as isochronous phase timing.
An inverter running off a car is not
as strange as it sounds. Many utilities run
power from their trucks using large
electronic inverters, including power
companies. This allows them to have
power when the grid is unavailable, and
it is electrically isolated from the grid.
Many RVs and motorhomes are running
generators and inverters as power options.
Most generators have a bonded
ground, meaning the neutral wire is
connected to the chassis and ground.
Once it is connected to your service
panel (via a grounded cable), its neutral
is locally grounded. Not connecting neutral and ground correctly is a potential
safety issue; not a guarantee of death
and destruction, but it could be. Proper
electrical wiring and use is a good habit
to follow. I cannot safely advise you
otherwise, but if you are in doubt about
the operation of your setup, again, consult your manufacturer(s), or a power
consultant. If you have any doubts about
your ability to work with home power,
it is best to enlist the services of a qualified and licensed electrical contractor
to do the necessary work. Also, I am not
recommending you leave an inverter
permanently connected to your furnace,
only as a temporary measure until either
power is restored, or until you can get
an alternate power source in place.
I really like your magazine. Every
issue has something useful. Your last
issue had an article about iPod
interfacing, which does not interest me,
but the pinouts for USB and the
schematics for the electret preamp and
RS-232 interface were great.
Ron Hackett made a compelling case
for the PICAXE in his recent article series.
It comes down to an extremely low cost,
and fast development and prototyping.
Unlike most Stamp-like devices, this one
can be purchased at very low prices,
making it affordable for the very small automation circuits that don’t justify a $50
MCU controller. Also, the fact that we
don’t have to buy a separate compiler or
hardware programming device makes the
PICAXE a “no brainer” purchase! By the
way, there’s a small typo in the link for
the maker of the PICAXE — you need a
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