Making wooden blades with Max

Posted on 20/05/2012 by hugh

A well made video by Max ‘Menelaus’ of www.kleinwindanlagen.de showing how to shape blades using a bandsaw and power sander.  It’s also interesting to note the reduced number of steps in the process compared to the procedure in my Recipe Book.

I like making things simpler although I have some doubts about the thickness of the result.  And I also have doubts about whether I would enjoy all the noise and the dust.  I like to use a sharp plane and I enjoy ‘surfing’ the wood with a draw knife, but if you want a quick result then this may be the best solution for you as for Max.

 

Posted in construction, People, Video links | 11 Comments

Photos of the Scoraig wind turbine building workshop

Posted on 12/05/2012 by hugh

Last minute adjustments

Participants: 6 (Robert, Jonathan, Kostas, Benji, Yanti and Kern)

Dates: 5-12 May 2012  Location: Scoraig.

Project: 3 metre machine using ferrite/ceramic magnets at 24VDC

Poles: 10, (3 magnet blocks 50 x 50 x 20 per pole)

Coils: 12 (37 turns of 2 x 1.6mm wire)

Target cut in speed (recipe) 170 rpm

Application – the croft next door to me (for sale) on Scoraig.  24V system and 20 metre tower with dead Samrey prototype on it.

Accommodation the bunkhouse, Scoraig.  Full-on home made food and frivolity.

The following video shows Jonathan helping me to put Paul’s (green painted) blades onto the zebra turbine.  We also increased the air gap a little to make sure the magnets did not rub on the stator.  The cut in speed is a bit higher than I would normally choose for a 3 metre turbine (195 rpm for 24VDC) but it runs very smoothly, and will definitely not stall at least.

Posted in construction, courses, ferrite magnets, my own projects, Scoraig | 17 Comments

Operation of school wind turbines suspended in Highland Region.

Posted on 12/05/2012 by hugh

Following enquiries from councillors and members of the public, The Highland Council commissioned the Building Research Establishment, an independent organisation, to evaluate all wind turbine installations on or adjacent to school sites.

Based on initial feedback from BRE, the Council has taken immediate action to temporarily suspend operations at all 16 school sites until the risks are fully assessed and any additional measures deemed necessary are undertaken.

BBC report here.

This one was right in front of the school and it threw debris around when it failed.

 

Posted in UK small wind scene | 2 Comments

Upcoming course in Ireland

Posted on 28/04/2012 by hugh

On 18th June I will be joining Jimmy and Miriam of Eirbyte for another fun workshop course.  Facebook page is here.  More information here.
Here is a video of a previous workshop with Eirbyte:

See this page for a calendar of all my courses.
And this page for a calendar of similar courses worldwide.

Posted in construction, courses, Video links | 2 Comments

Power curve measurements from Comet-me

Posted on 14/04/2012 by hugh

Noam Dotan at Comet-me in Palestine (Community, Energy and Technology in the Middle East) has been sending me some interesting data from the 4.2 m diameter turbines that they  build.  The design is based on the recipe but they use 20 magnets and 15 coils to increase the efficiency and the maximum power of the alternator.

Here is a scatter plot of power v. windspeed for the battery-charging version from last year.  It’s interesting to see how the turbine performs better at higher battery voltages in high winds.  At low voltage the tip speed ratio drops below 5 and the turbine stalls.

Lately we are seeing data from the grid tied (Windy-Boy) version of the turbine that is linked to the battery via a local grid created by a Sunny Island inverter.  Using variable voltage improves the efficiency of both the blades and the alternator in stronger winds.  Higher voltage keeps the tip speed ratio up and reduces the heating of the stator by keeping the current down.

Just now I have a visitor on Scoraig, Jon Leary, who is setting up dataloggers to measure the power v. windspeed curves for some turbines here.  We are trying to follow the IEC 614200-12-1 standard in so far as is practicable, including the ten minute averaging interval.  We are using a Logic Energy mobile logger for the first tests on a 1.8 m diameter turbine.  It’s exciting to begin to see measured data for the recipe turbines.  This can be compared with wind tunnel tests reported on the WindEmpowerment site.  The wind tunnel helps to shed light on the effects of Reynolds number and yaw angle etc in detail, whereas real world testing is the only way to determine the real world energy production of a turbine.  In fact earlier standards documents for wind turbine performance testing explicitly exclude the use of wind tunnel data.

 

Posted in CometME, products/technical, Scoraig | 1 Comment

Coleman wonder turbine gives 3x the Betz limit!

Posted on 11/04/2012 by hugh

Thanks to Doug Selsam for this helpful commentary on the Coleman 600W turbine that is only 2 feet in diameter and produces three times the notoriously obsolete “Betz limit“.

Posted in products/technical, Rooftop madness | 4 Comments

Helix Wind Asset Sale

Posted on 10/04/2012 by hugh

The company’s largest creditor is requiring that the assets of Helix Wind Corp and Helix Wind Inc, both Nevada Corporations, be sold via a public auction held at the company’s office on May 11, 2012 at 11 a.m. Pacific Time

It should not surprise us that this very inefficient design of turbine should ultimately end as a financial failure after all of the hype has been exposed and the customers have had their expectations unfulfilled.

With a cut-in speed of 5 m/s they recommend it be placed on a 15 foot tower in sites with mean windspeed 7 m/s but at the same time they recommend urban rooftop mounting.  The wind resource on urban rooftops is generally quite poor.  It’s a nice ornament, but at $17,500 USD it’s well over-priced.

Both vertical axis designs and rooftop siting are foolish ideas that have cost a lot of people a lot of grief and brought the small wind industry into unnecessary disrepute.

Example misinformation from Helix website:

Posted in products/technical, Rooftop madness | 6 Comments

Jan Wolstenholme’s construction blog

Posted on 09/04/2012 by hugh

Some novel approaches to small wind turbine construction including setting coils in concrete…

The Wind In The Wires

home built off-grid windturbine adventures
by Jan Wolsetenholme.
Posted in construction, People | 2 Comments

WindTracker – for Small Scale Wind Turbines

Posted on 07/04/2012 by hugh

Logic Energy have brought out a low cost but decent quality datalogger for wind.

This logger simply gives you the basic info that you need which is the windspeed distribution – how many hours the wind has blown at each windspeed.  Combine this with a power curve of a wind turbine and you can figure out the energy you would have got at that site.

Power consumption is minimal, and download is by inserting an SD card briefly to obtain the data file.  WT is fully made in UK under iso 9001 and EMC certified.  It’s weatherproof, and for what it is it’s dirt cheap.

Now you just have to figure out what to mount it on…..

What about these ones:
10m :  http://www.radioworld.co.uk/catalog/large_mast_33_feet_extended-p-4293.html?osCsid=e36510917af19e0044e5072acf7bc69c
20m :  http://www.radioworld.co.uk/catalog/atm-65_11-section_portable_aluminium_mast_19_8m_65ftlong-p-5382.html?osCsid=e36510917af19e0044e5072acf7bc69c

Posted in products/technical, UK small wind scene, wind systems tutorial | 5 Comments

Turbike.org

Posted on 06/04/2012 by hugh

Turbike.org documents the progress of Sean Callagy‘s pedal powered alternator project in Ireland.

Anyone who is trying to build a pedal powered generator should find this site interesting.

The project is based on an alternator that we built with Eirbyte in a course there in 2010.  There will be another course this year in June.  It’s always a lot of fun building turbines with Jimmy and Miriam, so I hope you will join us there.

Posted in construction, courses, Notices, pedal power, People | 3 Comments