Secondhand Proven 6kW turbines

Sangster Electrical in Fearn have a number of secondhand Proven 6kW wind turbines available.  Call 01862 832683 for details.

P1040220

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Scoraig wind turbine workshop 2015

P1040145

We built a 2F machine last week here at Scoraig.  There were 6 guys in the crew plus me.

Ghalib, Hugh, Brian, Svend, Brian, Laurence and Lukas.

Some photos of the sunny week.   Thanks to the guys for sharing photos….

Galleries:

Brian Davison,  Brian Falster,  Lukas Myl 

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2.4m machine on test in Greece

Kostas sent me a power curve and a video of a 2.4m machine constructed from my 2005 publication “How to Build a Wind turbine”from the NTUA test site in Rafina . It’s similar to the same size model in my Recipe Book.

“At a point during the measurement campaign, we had some extreme weather conditions and I thought we would not brake the turbine to see what happens. It operated continuously for as long as the extreme wind lasted, which was for more than 48 hours, operating in average wind speeds of 90km/h. The highest wind speed recorded by the anemometer on the meteorological mast during this period was 31m/s.”

robust

I hope soon to be able to publish more performance data from the tests that Jon Leary and I did in 2013.

Posted in performance, power curve data, Video links | 1 Comment

Nepal Turbine Documentary

Dear Mr. Piggot,

I am the director for a feature documentary about Tashi Bista and his dream to install a wind turbine in Namdok, a remote village nestled in Upper Mustang, Nepal. Tashi used your recipe book throughout the entire process. We have been filming with Tashi in Upper Mustang for about three years now and we are happy to announce that the film is complete.

The film really captures a moment in which Namdok is on the cusp of change. Tashi learned about wind turbines through a man named Jorge Ayaraza who currently lives in India. He’s been working with wind turbines for years now. We just wanted to share with you Tashi’s project and information about the film. We have attached a trailer below. We can not thank you enough for all your work and for all this information to be open source. It is amazing and has really transformed lives! So thank you very much!

We would be honored to communicate with you in the future. Thank you for your time.

Trailer:

Tashi’s Turbine Trailer from Amitabh Joshi on Vimeo.

Best,

Amitabh Joshi & Erik Spink

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Courses are busy

My course in April is nearly fully booked now.  Just one place left maybe.  But there are a lot of other courses happening in the near future.

Tripalium in France are always busy with one course after another.

Los Portales in Spain

Dan Bartmann of Otherpower is teaching one at the end of April at Driftless Folk School, Viroqua, WI 54665, USA

500rpm are busy in Argentina.

Paddy Atkinson is teaching in Poland 12-17 May

V3 Power are teaching two courses in the UK in May also.

I try to keep an up-to-date calendar of course activity teaching how to build wind turbines using my recipes under the link for “courses” above.

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maintenance sur une petite éolienne

Maintenance sur la petite éolienne Colibri sur l’ecosite d’Eurre. Projet fait en co-opération avec le Greta sur le projet RET.

 

This Colibri machine design is based on my approach, using an axial flux alternator.  You can see some details of the fabrication here.

New Tripalium website

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scoraigwind.com is back online

My old homepage at scoraigwind.com is back up, after falling over a couple of weeks back. Thanks to the guys at Otherpower for hosting it for me over the last ten years. Thanks also to Irishsolar (eirbyte) for hosting this .co.uk site.  I am bringing both sites together at Irishsolar now.  I can recommend Irishsolar for domains, hosting and wordpress sites powered by renewables.

The old site dates back to the 1990s and is frankly a bit of a mess, which is why all the new stuff tends to be on this wordpress site instead.  But there are some good galleries of pictures of courses over the last 15 years and various other miscellaneous gems.  See the contents link for an over-view.  And somehow Google still likes to point people to my old site.

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Wiring loss in 3 phase wind systems

Here is a piece I did about AC and DC in 1999.  It explains why DC wiring is slightly more efficient than 3-phase AC wiring where the AC is feeding a rectifier (rather than grid AC which is at  higher voltage).  One way to understand why AC is less efficient is to notice that Ac current is intermittent, only using the wire part of the time, whereas DC uses it all the time.  So for the same peak voltage, DC is going to work better.

There is some confusion about how to calculate losses in the cables of a 3 phase wind system.  If the 3 wires are feeding a rectifier, charging a battery, then the current in the cables is dominated by the need to supply DC at battery voltage to the load.

The cables may change, but the current tends to remain constant.

 LOSS

Paul Gipe’s question 

What is the power lost in conductors from a 850 Watt permanent-magnet, three-phase alternator feeding a diode bridge rectifier delivering a nominal 24 VDC to a battery bank. The rpm, voltage, and current of the three-phase alternator varies with wind speed. There are three cables (conductors) between the wind turbine’s alternator and the diode bridge. There are two conductors from the diode bridge to the batteries. The conductors are #8 AWG with an AC resistance of 0.78 Ohms/1000 feet. There is 150 feet from the wind turbine to the diode bridge, and an insignificant distance from the diode bridge to the batteries.

The DC current is found by dividing watts by volts.  this gives 850/24 = 35 amps.

If you want to analyse situation mathematically, current in each conductor is 35 amps for 2/3 of the time.  The rms current in each conductor is therefore (2/3)^.5=0.82 times 35 amps = 29 amps (rms).  Resistance of each conductor is 0.78 times the cable run of 150/1000 feet,  giving  0.117 ohms.

Power loss is I^2*0.117

which is 2/3*35^2*0.117

which is 1/3*35^2*.234 for each conductor

which is 35^2*.234=287W in total.

This is a 34% loss!

An easier way to analyse the situation (which also give the same answer) is to say that at any given instant the DC current 35 amps is flowing around a circuit path with resistance equal to 0.78*(cable run in feet/1000).  Cable run is 300 feet for the full circuit.

Finally I should point out that the above is strictly only true if the internal loss is small.  As loss increases, the situation becomes much more complex, since more than 2 wires will start to conduct at once during the changeover.  But the above answer will be accurate enough for practical purposes, given that we are arguing about such large differences in our answers.

Hugh

October 1999

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Assessment of locally manufactured small wind turbines as an appropriate technology for the electrification of the Caribbean Coast of Nicaragua

This paper spells out the many hard lessons that were learned by blueEnergy in their effort to bring locally manufactured wind energy to remote villages on the Caribbean coast.  It should be read by anyone setting out to use my wind turbine designs for a tropical maritime local electrification project.

ABSTRACT HERE        FULL PDF HERE

I have always been inspired by blueEnergy’s principle of “sticking around” which I feel is the downfall of so many aid projects: here today and gone tomorrow.  But unfortunately, as you can read, there were numerous factors lined up against the success of using locally manufactured small wind in this situation – not least of which is the lack of wind.  No amount of enthusiasm and dedication can compensate for a low windspeed site.

Corrosion issues have been the biggest potential weakness in my published designs, and these are also spelled out.  Inexperienced workers, remote locations, lightning damage etc make for poor reliability and high cost in relation to the relatively simple and ever cheaper PV generated power.

See also video about How to encourage wind energy in Tanzania: NGO or private company?

Posted in developing world, People | Leave a comment

Hornet wind turbine next door

After the storm destroyed the Ampair 100 that was on this mast, a neighbour bought a Hornet from http://windgenerator.org.uk/  This is the 8-blade 1250 watt version.  Apparently it has been seen producing 1251 watts into a 24 volt battery “in the bottom of a valley”.  Which I assume would be about 40 amps and 30 volts.  However this is one on Scoraig is connected to a 12-volt system.

The Hornets are made by Hydrogenappliances in the USA and are a bit similar to the products of Missouri Wind and Solar (see below).  Converted car alternators and tiny composite blades.  The 28″ long blades look like copies of the AIR machine’s high speed blades but on the Hornet the alternator is stiff to turn so they use them in large numbers to get enough torque to spin in low winds, and this somewhat defeats the low solidity.  Furthermore they recommend cutting this tips off to get more power (?)

Having said all of that it’s an affordable little unit and when I went to look at it in a good stiff breeze it was purring along producing a respectable 50-100 watt output.  Let’s see how long it lasts.

Posted in products/technical, Scoraig, UK small wind scene | 20 Comments