Abridgment of
Cooperative Courses—Their Development
and Operating Principles
that the displacement of the crossarm is somewhat
greater on account of the necessity of taking up the
swing of the insulator string before the development of
the necessary opposing pull in the several conductors.
In this case, the outside conductor cable takes the greatest
stress as the crossarm will as before revolve in a
horizontal plane about a point near the far ground
wire.
The only serious objections urged against the post
type are the greater width of line structure, which is
controlling in only a few cases, and the use of guys,
which while exceedingly effective and economical, make
a widespread base. The utility of the post type
tower can be summed up very briefly as follows:
1. Sturdy and simple design.
2. No special skill or accurate leveling required in
setting footings or tower erection.
3. Best arrangement of conductors electrically and
as a safeguard against uneven ice loads.
4. Not sensitive to foundation movements.
5. A very material saving in weight and cost of steel
and in cost of footings, anchors, and erection.
It may be added that obviously many modifications
of the post type structures here shown may be made to
meet different conditions or uses.