According to Chris :

"JohnM" wrote in message
...

[ ... ]

Use an electric motor, you won't have the fumes and won't have to stop for
fuel. Just unroll the extension cord as you go to work and roll it back up
again as you come home.

A variable frequency drive would allow you to use a 3phase motor and have
speed selection, this would be an asset in traffic.

John

John,
Hate to bring up the normal response, but...

What gauge wire would that need to be for the extension?

The obvious response is:

How long does the extension cord need to be? :-) I figure just
over 15.5 A at a full 5 HP with a 240V line. You probably want no more
than a 10V loss over the length of the extension cord, so you want less
than 0.041 Ohms. So -- 4-0 wire would be pretty close at 1000 feet
total length (that is 500 feet away from the outlet).

0000 1000' total or 500' loop
#8 66' total or 33' loop
#6 104' total, or 52' loop
#16 10.3' total or 5.2' loop

If you insist on having 5 HP, you had probably better plan to
stick pretty close to home. :-)

Oh yes -- 4-0 (0000) is 640.5 pounds/1000 feet. :-)

Now -- you can reduce the current, and thus increase the
distance or reduce the gauge by stepping the voltage up high and
reducing it with a transformer on the bike -- but that would add enough
weight to neutralize the benefits. (Not to mention the extra cost of
high-voltage insulation on your extension cord. :-)

VFD would be nice, but lose about 1/3 of the HP on the motor. RPC might be
a better choice.

Huh? How do you expect to lose 1/3 of the motor's horsepower
with a VFD? With a so-called "static" phase converter (which in reality
is a starting capacitor and the necessary switching to take it out once
the motor is started), yes -- you would lose about 1/3 of the motor's
horsepower rating.

Now -- you might want to over-rate the VFD a bit if you are
going to be drawing full rating from it for long. But even a 7.5 HP VFD
will weigh a lot less than the 5HP motor. I know, because I've got an
old one on my shop wall.

Enjoy,
DoN.
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