Pedro’s microwave ferrite magnet turbine

Posted on 12/07/2011 by hugh

Pedro Bernardo has been sending me photos of his latest project using ferrite magnets from a microwave oven.  Pedro lives in a village close to a small city called Marinha Grande, Portugal.  (Since I first posted this message he has put all of these details on the Fieldlines discussion board.)

Stator with 9 coils (2 x 1.6mm wires)  46 turns, connection star/series, 13mm thick.

The generator had  two 6mm disks, 12 magnets each (microwave magnets in pairs at first), diameter 306mm.

The idea is to reach 12 volts close to 200 rpm, and use the recipe book 2400 mm rotor.  Bench testing showed a 12V cut-in rpm closer to 226 rpm.  Pedro then stacked on a third magnet level on each rotor and got the cut-in rpm down to 215 rpm.

According to my calculations this alternator should be comfortable at a power output around 400 watts with 40% efficiency.  This is compared with the neodymium version producing 700 watts with 70% efficiency.

However the magnets are much cheaper, and very durable.  Also the alternator speed characteristic is much more suitable for the blades.  The higher internal resistance of this stator helps to push the speed up as the windspeed increases, thus preventing stall.

I trust that Pedro will secure the magnets against flying away!

Posted in construction, ferrite magnets, People | 48 Comments

Eoltec 6kW turbine is MCS approved

Posted on 06/07/2011 by hugh

A (shortened) press release from Orkney wind energy company Bryan J Rendall Electrical:

The Eoltec Scirocco, co-developed by Kirkwall company Bryan J Rendall Electrical (BJRE), is the first wind generator of its kind to meet Class 1 standards under the Microgeneration Certification Scheme.  This means it is rated to withstand the extreme wind speeds experienced in exposed areas such as the north and west of Scotland.  The Scirocco is now the only Class 1 turbine eligible for Feed in Tariff (FiTs) payments.

The 6 kilowatt (kW) Scirocco has been certified as generating more than 10 per cent more electricity than its nearest rival.

Mr Rendall said the certification process had been extremely challenging, and at times very frustrating.

“We have achieved a Class 1 rating on what is effectively a shoe string budget,” he said. “Other manufacturers have had multi millions of pounds in financial help and investment to carry out this testing.

“We have done it virtually all in house, with only 14,000 (pounds) of much appreciated funding from Highlands and Islands Enterprise.

The BJRE Eoltec Scirocco 6kW wind turbine has been certified as having a Reference Annual Energy Production  (RAE) of 9881 kWh per annum in a mean annual windspeed of 5 metres/second.  This performance  is over 10% higher than its nearest rival, and over 12.5% higher than the next nearest, according to RAE ratings published on their websites.

(Note from Hugh – the Evance turbine is rated to produce 8780 kWh/year in a 5 m/s average.  The Eoltec Scirocco makes 12.5% higher than this figure.  Eoltec do not reveal what their energy production would be at other mean windspeeds.  The  “nearest rival” is most likely the Proven 11 which does not as yet have MCS certification.

The vertical axis QR5 now also has MCS certification, but the rated output is only around 2000 kWh/year at 5 m/s wind.  This VAWT performs best in decent winds, but I only ever see it sited among buildings and trees where windspeed can’t be more than 3-4m/s annual average.)

Posted in UK small wind scene | 27 Comments

Wind turbines in Tajikistan

Posted on 22/06/2011 by hugh

Tajikistan

Jarty Gumbez #4 from an album of photos by Tony Nelson, Director etc4ca

Posted in developing world, People, products/technical | Leave a comment

Source for wind turbine parts/kits in France

Posted on 20/06/2011 by hugh

ventetsolaire“We provide parts, completed sections  or the complete 2.4 metre wind turbine kit for the enthusiast to create your own micro electricity generating station by using the wind as the natural resource.  This can then charge batteries or be used with a grid tie inverter (see product list).”

This site offers parts for my older 2005 design wind turbine in France.  Also an interesting little inverter for grid connection.

Wind turbine building parts are available in the UK from

www.Wind-Turbine-Supplies.co.uk

and in the USA from

www.forcefieldmagnets.com

and in Australia www.thebackshed.com although they do things differently down there 🙂

 

 

Posted in construction, France, People, products/technical | Leave a comment

Otherpower workshop at Buckville CO

Posted on 18/06/2011 by hugh

For those of you who do not read the Otherpower discussion board at Fieldlines, well, you should.

Here is a recent posting about a workshop at Buckville CO.   Dan Bartmann, George and Scottie guided a small group to build an ambitiously large turbine.

DanB has recently posted about a couple of other workshops they did at the Midwest Renewable Energy Association in Wisconsin here and here

These are not only good stories, but also contain a lot of technical details for the latest 12 foot machines being built.  “This is a 48V turbine, we wound the stator with two strands of AWG 15 wire in hand and 64 turns per coil.”, “We hit 48 Volt cutin at 125 rpm as usual.”  and “In an effort to fit as much copper as possible into this stator, we wound the coils (24 volts) with 33 turns each, using 4 strands of AWG 15 wire.  ”

The the 15 inch diameter rotors look lovely with their 2″ diameter, 1/2″ thick N42 neo magnets on (which cost $20 each now!)

My recipe book calls for 45 and 90 turns of wire(14 gauge), which has a higher resistance.  I use smaller 2″ x 1″ magnets, on a larger (16″) rotor disk.  I have a philosophy of using larger stators and less neodymium.

The Otherpower design can hit a higher peak power, but my alternator will be less prone to stalling the blades.

The Fieldlines discussion board is a good place to get advice, see what works for others, and be amazed.  Otherpower are the best guys at running workshops for homebrew windpower and related topics.  Check their web page Otherpower.com for dates and venues.

Posted in construction, courses, People | 3 Comments

Furling turbine video

Posted on 12/06/2011 by hugh

Here is a video of the machine that we erected at the end of the workshop in May.  It shows the tail furling as the gusts hit the 3 metre turbine on  a low tower in turbulence.  At one point the brake switch is applied and you can see the blades come to a halt in about one second.

You can find a lot more videos on my YouTube page.

Posted in construction, courses, Video links | Leave a comment

Scoraig course 2011 photo diary

Posted on 04/06/2011 by hugh

I made some pages about the recent workshop course here at my home on Scoraig last month.

The finished blade

Overview

Blade

Magnet placement

Coil winding

Assembly

Testing

The next workshop course will be at CAT in Wales on 28th August.

After that in Ireland 12-17th September

Full construction ‘recipes’ for the wind turbines are for sale here.

Posted in construction, courses, Scoraig | 1 Comment

Recipe Book updates

Posted on 26/05/2011 by hugh

I have been active updating my Recipe Book lately.

Check out the updates page for details

Posted in Books, construction | 11 Comments

PDF book about electricity supplies in Africa

Posted on 26/05/2011 by hugh

Energy for Radio – A Guide for Practitioners

Michael Bycroft

“Energy for radio” is a guide to energy management for community radio stations. It supports radio managers and operators as they tackle the energy issue at their station, helping to understand the various sources and technologies of energy, especially gensets, wind and hydro turbines, solar and hybrid systems. The guide also views many other aspects requiring attention before “informed decisions” can be taken, including assessment of the energy needs, storage, protection and regulation.

The worksheets for assessing the energy needs of the stations as well as cost-effectiveness of different energy sources are available for download.

The author: Michael Bycroft is a science journalist based in UK, with a special interest in green energy technologies and climate change.
The publication is sponsored by the Dutch foundation Stem van Afrika.

Web link where you can order paper copies or download the book or the worksheets for free.

Free download

I helped with advice in the preparation of parts of this publication

Posted in Books, developing world | Leave a comment

20 – 23 May 2011, Holland

Posted on 08/05/2011 by hugh

How to build your own wind turbine workshop

A 4 day workshop is going to be given starting from 20 May in Helvoirt, The Netherlands. During this hands-on workshop a 3 [m] rotor diameter wind turbine will be made by the group and if time allows another small one. No skills are required to participate. The profit will go to a non-profit project, where disadvantaged people in developing countries will learn how to make such turbine. If you are interested please follow the following link.

This will be a good event run by experienced people with an exciting project happening in Africa.

Posted in construction, courses, developing world, People | Leave a comment