Wind Generator Project

Overview

I have long thought about building a wind generator as I rather like the idea of power for free provided by the elements. I also have another motive, that is a remote power source while camping. I have a 12V electric fridge and I like my beer cold even though I'm miles from anywhere, aw yeah, and the milk. So my design is ultimatley portable and small.

My wind generator project is inspired by Hugh Piggotts work, ideas and designs along with others. I recomend his book "Wind Power Workshop". I decided early on what I didn't like was the generator designs many people used. Gearing and pulleys was not the way to go. Nor was a homebuilt one requiring hours of effort. Permanant magnet DC motors or alternators seemed to be the way to go but are not readily avilable to me nor of any significant size.
I found a link on the web and since then other people where single and three phase AC induction motors were converted to permanant magnet alternators by simply glueing magnets around the rotor. This seemed to me the way to go.

The stator

I found a 1/3 HP motor out of a washing machine.
This is the motor dismantled and showing the stator

The Rotor

I turned the rotor down in a lathe and glued magnets on and fiberglassed a layer over top for strength. The magnets I aquired from New Age Materials a computer wrecker here in NZ.
Eight magnets are fitted around the rotor is groups of two of the same pole. A magnet is of the same pole as it's direct opposite and the magnet 90 degress from it is of the opposite pole. This is because the motor is wound with four poles with every second pole or winding is wound in reverse.
It took me a while to figure this out as it's very hard to trace the windings.

It's characteristics seem good with it generating 12.5V out at 67 RPM. Thats a little over 1 rev a second.

Yaw hub

I made a Yaw assembly to fit a Yaw bearing mounted in the nacelle shown here upside down. In this Yaw hub is fitted a second smaller bearing insulated from the main body and serves as a slip ring for the second wire down the tower. The metal frame is used for one wire.

A electrial eye terminal is fitted under one of the screws and a wire is run down the tower which is 2" pipe.

The nacelle upside down

Seen here is the Yaw bearing and spring loaded probe to make contact with the insulated bearing in the hub at the top of the tower.
The main advanatge of this system is no connection or disconnection is required when dismantling or assembling.

The nacelle is simply placed onto the top of the tower and electrical connections are automaticaly made. This is part of my idea for a portable system.

I am not sure if this will stand up to the test of time as the bearing may suffer from arching and may eventually fail.
The motor had two windings which I have wired in parallel through two bridge rectifiers which can been seen as the black objects.

You can seen the wires running to the spring loaded contact for the wire down the tower. The Yaw bearing hub is fix to the top of the tower (Black pipe).

Testing

Some early testing in light winds. A Voltmeter, Ammeter and variable active load are taped to the pole.

Power Output Results

Unfortunatly the power output is a little disapointing, but it does work non the less so I suppose it's not all bad.
But do note the very good low RPM output voltage or startup RPM. This will be due to the motor windings being orignally 230V, but at the cost of producing low current at low voltage (low power)

The orignal motor had two windings, a start and a run winding so results for the two windings are shown.
The lower output winding graph shows how impedence matching is important for maximum output (around 20 ohm load).

Note the orignal motor is 1/3 HP (~250W)
Total Possible output shown from data ~ 85W
So using this method expect around 1/3 of orignal motor rating

Resources on the web

Generators

Windmill Permanent Magnet Alternator for Generating Electrical Power
New Age Materials - Electronic and catalytic materials recycling - My magnet source for my generator.
NIB magnet alternator test
Induction motor to permanent magnet generator conversion - The main idea behind my conversion.
Permanent Magnet Generator booklet - By Hugh Piggott - A built from scratch generator.
Homebuild wind generator using car alternator
Lindsay: Armature Winding & Motor Repair - General Motor Concepts.

Blade design and construction

Carving Blades - Used to carve my blades.
BASIC BLADE DESIGN - Design principles used in my design.

Wind generator projects

Andrew's - Build your wind turbine - A larger but similar idea and design to mine.
Troubled Times: Home Made
Wind Power in Canada:Building your own windmill
Build Your Own Wind Generator!

General Resources

Windpower Monthly News Magazine: Windpower Monthly Home Page
Ray Toms,Alternative Energy Specialist Home Page - Taupo, New Zealand
Waterwheel-powered house
PicoTurbine Renewable Energy Windmill and Solar Projects
Wind Power
The University of Newcastle Wind Energy Group
Wind
PTL - Windpower
Small Wind Systems Site: Table of Contents
DESIGN, CONSTRUCTION AND TESTING OF A SMALL WIND GENERATOR WITH ELECTRONIC CONTROLLER FOR DOMESTIC USE
SMALL SCALE WIND ENERGY SYSTEMS
A 2KW homebuilt inverter.
Various homebuilt stuff


2002 James Whyte. All rights reserved. No content herein can be used or reproduced in part or whole

without the express permission of James Whyte.