20 Foot Page 6 - Tower Part 2

tower base

We wound up having a bit more concrete than we knew what to do with so we piled it pretty high around the tower base.

rigging the gin pole

First step once the concrete got hard was to rig up the gin pole and prepare to raise it. The gin pole is 37' long. We have it guyed on all sides. We put the bottom 10' of tower in to use as a 'gin pole' to raise the gin pole!

guy wire anchor

Pictured above is a finished guy wire anchor. The shackles are necessary to allow the turn buckles to pivot as the tower goes up and down.

gin pole coupler

This shows detail of the gin pole coupler. Notice how we welded it to both pipes in a couple locations.

up goes the gin pole

Up goes the gin pole! We used a heavy duty hand winch (come-along) to pull it up. It was quite heavy to pull up this way, the forces on the come-along were probably similar to those that the winch sees when we actually raise the whole tower .

gin pole pully

This picture shows detail of the end of the gin pole. There's a 3/8" cable that's snatched to the pad near the winch, then it goes up over the pully and then back down to the winch. This divides the force that the winch sees in half. To raise the tower the winch will have to take up almost 100' of cable. The other cable you see wrapped around the end of the gin pole is a temporary 'guy' wire we had to put on to hold it up when we raised the gin pole. This came off as soon as we got the gin pole back down(and the tower up).

Building the tower

Here we're building the tower. Pretty quick and easy - in the picture we have about 50' assembled.

hi - lift jack

The hi-lift 'farm jack' is handly to hold the ends of each section at the right height, so the tubing goes together perfectly straight when we tighten up the couplers between the sections.

top guy wires

This is where the top guy wires hook in. The top guy wires are 3/8" steel cable, below that we used 1/4" stuff.

load testing the tower

First I raised the tower just a little bit to see if the winch could handle it/if every thing would work. Then we put 4 folks on the end (About the weight of the wind turbine and the tower stub) to test things again. The winch wasn't up to the task - the motor stalled. It turned out to be an issue of bad power to the motor though - too much line, too much voltage drop. By moving a 6KW generator right up to the winch the problem was solved.

winch spool

This is the winch while raising the tower. The cable spooled up very nicely on there - this worried me but it worked out better than I expected.

Up she goes

There it is on our first test raise. It goes up very nicely/smoothly - slowly. No bouncing or vibration at all - the process takes about 7 minutes.

tower stub

This is the stub for the top of the tower that will fit the wind turbine. It weighs 90 pounds!! It consists of 36" of 4" pipe sticking up. We had to forge/weld 1/4" barstock around it and sand it a bit for a nice fit to the 5" pipe on the wind turbine. At the top we've mounted a throwout bearing from a model A Ford to serve as a thrust bearing. The bottom of the stub is made from 10" diameter sched 40 pipe that fits tightly over the 10" tubing from which the tower is made.

Now we have all the parts - alternator, blades, tower... all that's left is to assemble it all and see what happens.