SCIENCE

Science

Science

PART I: SCIENTIFIC METHOD

Scenario 1: You arrive home late at night. You walk up to the front door, unlock it, and reach in to turn on the light switch located just inside the front door. The light does not come on! Now what?

No electricity equals no light pollution. However, it would be nice to have at least a little electricity, since so much of life in the 21st century is dependant on it. The problem is, it's so remote that there is no electric service available. I would be so mad to see this situation at that time. (Kuhn 2009)

 

Scenario 2: Develop your own detailed problem/observation and apply the scientific method to solve.

Several years ago I bought some remote property in Arizona. I am an astronomer and wanted a place to practice my hobby far away from the sky-wrecking light pollution found near cities of any real size. I found a great piece of property. There was no electricity there. I started the process of designing my wind turbine by Googling for information on home-built wind turbines. There are a lot of them out there in an amazing variety of designs and complexities. All of them had five things in common though: (Kuhn 2009)

A generator

Blades

A mounting that keeps it turned into the wind

A tower to get it up into the wind

Batteries and an electronic control system

Once the that voltage is exceeded, the turbine suddenly has a load as it begins dumping power into the battery. Once under load, the rpms only slightly increase as the wind speed increases. More wind means more current into the battery which means more load on the generator. So the system is pretty much self-governing. I saw no signs of over-reving. Of course in storm-force winds, all bets are off. Switching the controller to dump power into the dummy load did a good job of braking the turbine and slowing it way down even in stronger gusts.

Actually shorting the turbine output is an even better brake. It brings the turbine to a halt right now, even in strong winds. Shorting the output is how I made the turbine safe to raise and lower, so I wouldn't get sliced and diced by the spinning blades. Warning though, the whole head assembly can still swing around and crack you hard on the noggin if the wind changes direction while you are working on these things. So be careful out there.

I reduced the project to just five little systems. If attacked one at a time, the project didn't seem too terribly difficult. I decided to start with the generator. My online research showed that a lot of people were building their own generators. That seemed a bit too complicated, at least for a first effort. Others were using surplus permanent magnet DC motors as generators in their projects. This looked like a simpler way to go. So I began looking into what motors were best for the job. Eventually I decided my setup was too messy and ...