WHISPER 100/WHISPER 200 24 Foot Tower Manual
Document #0026 REV E
SOUTHWEST WINDPOWER
5/20/05
6
distance is required between your tower and the batteries it will be necessary to use heavy gage
wire to reduce the resistance of the wire. The power consumed buy the wires can be calculated
using the formula:
Power = Current
x
Current
x
Resistance
Since the resistance of the wire is directly proportional to its length, making the run shorter will
dramatically reduce the amount of power “lost” in the wires. See your turbine owner’s manual for
wire sizing charts.
Please refer to the section on “Tower, Base and Anchor Layout”. The amount of space available to
assemble and raise the tower may also affect where your tower can be placed
Step 2: Mast and Hardware Selection
Because of the high cost of shipping and the widespread availability of the tubing or pipe used for
our towers, these materials are not provided by Southwest Windpower. These materials are readily
available through most chain link fence suppliers or plumbing companies and will cost much less
when purchased locally than if we were to try to ship them from our factory.
The “Whisper” land tower kit is designed to use a 2.875 in. (73 mm) outside diameter pipe. This is
the same outside diameter as 2 ½ in. steel water pipe where the “2 ½” is a nominal size indicating
an outside diameter that is actually 2.875 in. Whether the pipe is “schedule 20”, or “schedule 40”,
the outside diameter will be the same and the schedule number determines the wall thickness of the
pipe.
Use only structural steel for this tower! Never use electrical conduit!
The design of this tower kit allows steel pipe (or tubing) of various different wall thickness to be
used depending on its availability and on the severity of the wind at your site location. Use the
following table to determine the acceptable pipe size(s) for your tower and wind severity. In most
locations structural pipe with a wall thickness of .090 inches (3 mm) is sufficient for the conditions
and preferable in terms of cost and ease of assembly. We recommend either “CQ-40” or “S-40”
fence pipe available from any chain link fence supplier. Electrical conduit or plastic tubing should
never be used in your tower assembly, since it is designed to be bent easily, not for strength.
Use the following table for Pipe / Tubing wall thickness guidelines:
Maximum
Wind Speed
80 mph. (135 kph)
100 mph. (160 kph)
120 mph. (190 kph)
Recommended
Wall Thickness
.090 inch (2.3 mm)
.120 inch (3 mm)
.140 inch (3.6 mm)
Pipe
Schedule
CQ-20
CQ-40
S-40
Pieces of Pipe Needed:
(1) 24 foot
(7.3 M) length of pipe for tower (wall thickness selected for local conditions)
