On Sun, 25 May 2008 21:48:51 +0000 (UTC), David Lesher
wrote:
Bruce in Bangkok writes:
All distribution transformers, sometimes called "pole pigs", that I
have seen had some sort of voltage adjusting system, usually referred
to as taps. Usually they are an actual bolted "tap" and you open the
transformer and set the output voltage by making the proper tap
connection when the transformer is installed and frankly it is usually
ignored thereafter.
The pole pigs here [7200v in/120-240 out] are fixed tap, I'm told. Saves
money. I think they are fused at 10A in. Older ones may have settable taps.
Don't generalize too much. Multi-tap transformers are the normal for rural
co-ops. I have a couple sitting in my shop right now. It's cheaper to change
taps on the transformer than it is to deal with the various voltages that
happen around a large geographic area.
I envy EU houses. If we had regular 240V/30A+ outlets, I'd be able to
buy a snowblower with real guts. The 120v@15A ones are wimpy.
You can have as many of those outlets as you want. In fact, I did just that
in my restaurant. Every place there was an outlet I installed a double ganged
box and included one 20 amp 120 volt outlet and one 30 amp 240 volt outlet.
I'm doing the same thing here in my cabin as I slowly rewire it.
UK appliances are available on the net. A 4kW tea kettle beats the hell out
of a puny 1700 watt 120 volt version. Same with a commercial 240 volt
toaster, coffee maker, etc. All I have to do is change the plug, getting rid
of that UK abomination. Some of the e-stores sell appliances sans plug, aimed
at the european market. The customer installs whatever plug is used in his
country.
For a snow blower, why not make your own? Find one with a blown engine or buy
a new one and sell the engine. Install a suitable electric motor and away you
go. You can figure about 2/3s the HP of the gas engine is necessary for a
normal high torque farm-duty motor.
If I were going to do that, I'd probably go a step further and use a 480 volt
motor along with a 2:1 autotransformer at the house. That way the cord can be
much lighter, something to think about when you're slaving away out in the
white stuff.
Depending on what I could find and at what cost, I might even go with a 3
phase motor and VFD. The VFD will take single phase 240 as input and generate
480 three phase output and at whatever frequency you desire. Considering the
cold operating environment, you could spin a smaller lighter motor faster and
get more power than with a straight 60 hz motor. You could even have a
"throttle" (a potentiometer) on the snowblower. Small VFDs (10 hp and less)
are fairly easy to find used. For that matter, they're not all that expensive
new.
John
--
John De Armond
See my website for my current email address
http://www.neon-john.com
http://www.johndearmond.com -- best little blog on the net!
Tellico Plains, Occupied TN
No one can be right all of the time but I'm getting close.