Archives : 2002
3rd April 2002
POSTMORTEM on EXPERIMENTAL WIND TURBINE
We concluded a postmortem on the hybrid Survivor wind turbine which ran behind Rainbow Power factory for nearly ten years. This machine was significant in that it had run very well and earned its keep, even in the light wind regime of Nimbin. It was the subject of Kalis paper to ANZSES in Darwin after it yeilded magnificent performance figures. Its electric components were essentially the the same as the Flowtrack machine, but smaller, and missing the stall governor.
In its gearbox the pinion on the generator was cantilevered off the generator and was held on by a drawbolt which persistently worked loose. We tried many methods of securing this gear - Loctite, bent tabs, low tensile boltss etc. Being on the generator it suffered thermal cycling, vibration, lash, and reversing axial forces because the teeth were helical. The final failing was that excessive clearances meant that working on the locating tang on the drawbolt eventually broke it. Then the teeth were chewed off.
Eventually the gearbox jammed. This halted the wind turbine very quickly and the gyroscopic forces on this vertically furled machine sent the blades into the tail.
Remarkably there was no dangerous structual damage caused, just some tears in the trailing edge fairing of the fibreglass. All credit is due to the much maligned Survivor turbine that its blades can take such severe abuse without any failure of the hub or blade roots.
THE BATTERY DEAL
The grape vine had it that our local scrap recycler had half a dozen pallets of batteries cheap. They looked great - less than four years old 240AH GNB cells. A test cell made 350 amp hours at the 10 hour rate when we tried it. We noticed a few had the positive posts broken off and assumed it was rough handling. Then a few more were found to turn round and round and make intermittent contact inside the cell ... Then we found that ALL of the cells had severe corrosion of the positive posts, disquised by the fancy tube of polyolefin encasing them. It is not obvious whether this was to facilitate post casting or an attempt to prevent corrosion, but we did discover that there had been a three way argument between GNB, TELSTRA, and the install company about this feature ...
We all had theories about the fast post corrosion: bad lead, unmixed makeup water floating on top, excessive float voltage, oxygen rich air getting to the acid level down this post tube, disimmilar types of lead joined, and so on. The result though was that we had to rip into the cells and weld on new posts! Messy.
Our long history of tolerating bad and expensive (in our opinion) service from TELSTRA led to dreams of our own telephone network. Now with cheap computers we have implemented a data phone system on cheap lines through the lantana which connect to modems at the ends and can link to an intranet. We have a wonderful array of non-micro$oft applications and operating systems running in various degrees of integration on this intranet. The computers vary from a newish machine running Redhat Linux to an XT running DOS.
This page could actually be coming to you from a 386 running DOS ... !
DOS is old, but not obsolete. This html is being written on a DOS machine. There are impressive, fairly recent programs written for DOS that have the advantage of being cheap, open source, relatively virus proof, small, and reliable. The truth we dont advertise about the train traffic control softwre is that behind the fancy graphics is good solid DOS.
Check out (http://www.fdisk.com)
TONY LEAVES FOR KOREA
Tony Megs who carved the wooden blades for our machines has been offered a job in Korea - teaching English! We are of course a little shocked. There must be nearly a billion speakers of English on the planet but not many who can make timber turbine blades that work. We are going to try to make a machine for copying previous efforts.
So far his trip has been miserable with a VISA card gobbled up by a machine at the airport, and a tooth broken on a mintie. Also the work turned out to be only part time. We hope he continues to have bad time and comes home ;-)
MINITORCES BECOME POPULAR
Rainer's minitorches are in greater demand. The latest ones have a momentary switch and a 30 second timer.
They are very easy to pocket and very reliable. Other companies have been approaching us to get their logos on them and we have been making hundreds. New superbright LEDs built on SiC semiconductor have made green, blue and white LEDS practical and the light has some spectral spread. Changing electrical wiring at night by the light of a yellow minitorch is very dubious :-(
KALI GETS TO BUILD ROAD
After years of legal dispute over access to the old McLaughlin selection, lot 286 Lorne parish map, at last there was a way between the new and mooted real estate developments. The civil engineering was not trivial thanks to spurs off ridges which were hiding in the sea of lantana. The result is a kilometre of winding road with some interesting bends!
ACRE PULL OUT of WIND DEAL!
For nearly a year now there were complex negotiations between ACRE, BEST, Cummins, Flowtrack and Tunra (Newcastle University) to do a deal whereby Cummins got to build our wind turbines in Adelaide, ACRE got the blade technology, Best was able to sell out its interest, and of course the original obligations to ERDC would be honoured. Flowtrack was served with a Quit Claim by Owen Legal services in order to sell the wind turbine design, but because there was no reciprocal manufacturing agreement with Cummins in evidence we did not sign. This apparently was not the real holdup in the deal however. A deeper problem seemed to be that ACRE wanted something for nothing, and were hoping to finesse the blade technology out of unifying the various stakeholders into a presentation to Cummins. Cummins turned out to be unwilling to get into such a difficult venture at a time when the Adelaide operation was in doubt, and having downsized some relevant staff out of the organisation. This all leaves Flowtrack with little money, but the ability to start manufacture.
TRAIN CONTROL SOFTWARE
The name of the company is amazingly suitable for another breadwinner continuing this year - writing software for train traffic control! The name "Flowtrack" was coined as a description of the Power Point Tracking of the wind turbine, but keeping trains running well on their tracks is also well described by the name. Several contracts have related to changing the display colours of the traffic control software from the actual signal colours to that which occupational health and safety will tolerate - no black red, green and orange! Now the big test is to supply a hot-swap computer which keeps ready for the changeover in the event of a computer failure. Computer failure is actually one of the least likely reasons for train stoppages - unless somone has been playing microsoft gamees on the work computers (!) and let that presumptious operating system trash the modem profiles. No - the real problem is trying to use TELSTRA lines in the bush to carry traffic information. There have been enough problems with the remote temperature sensing systems trying to get a modem to work on a bush line.
Another workshop diversion from the main business of wind turbines has been miniature torches sporting the new superbright LEDs. Economy models with amber light have been selling like hot cakes, and experiments are in progress with multicoloured ones, and torches with a timer switch which is requested by people running caving trips and similar events where the reliability and robustness of the LED torches is the go.
More Microgrid controlled rectifiers also have been in production. Power electronics is at least closer to core business.
KITTANI SANCTURARY MICROGRID
The Kittani Sactury Microgrid is now running. A quantity of material has been placed on the DOWNLOAD page on this site to explain how Microgrid as a technology relates to small wind power, and in a sense the consumption side of the equation is as important as the generation side. The Kittani Microgrid has no wind contribution as there is no wind there! It has however considerable decentralised solar and a wonderful variety of inverters, batteries, and house wiring in the ten house community.
However the Adjinbilly microgrid near Killarney, QLD has come to sad times. It is another system with no wind input after our survey on a nearby mountain yielded the miserable average of 2.5 m/s average! It does however have a nice microhydro generator which is good for 12 kWh a day. Stage two of this ecotourism development faltered at a relatively advanced stage and sank the whole project. Flowtrack had completed a 5kW hydro generation feasibility study for the relevant section of the Condamine. One reading of the project is that excessive feasibility studies and environmental requirements drained the financial resources. (not ours though as we have not been paid!). There appears to be a local "food chain" based on land development.....
Technically the Adjinbilly system was notable in having the first 40 amp downconverter which worked well (but also was not paid for!)
The prototype of a new product is now running. It is simply a rectifier from 240 volt mains to 100 volt microgrid, but implemented with a new topology. Previous units were SCR controlled rectifiers with voltage and current feedback. These had several defects:
*Poor power factor and input wave distortion
*sensitivity to input voltage and frequency
*poor response time to demand fluctuations
*No fail-safe in the event of semiconductor malfunction. This required the installation of large "crowbar" thyristors.
The new rectifier is of 20 kHz switchmode design and is rated for 750w continuous. Derating will not be necessary when operating from sources with high harmonic impedance, such as small gensets.
AusWEA FORUM - LATROBE VALLEY
The newly formed Australian Wind Energy Association held its first event on 27th April at Churchill in Gippsland. It was attended by many in the wind industry and was generally judged to be a great success. A full programme can be downloaded from the new AusWEA web page:
After the many excellent reports to the forum and solid question and answer sessions there was a tour of factories in the Latrobe valley. Skilled Engineering contained some impressive milling machines and gigantic lathes, and Siemens plant excited us greatly as we saw the ring generators of Lagerwey windturbines actually being assembled, wound and dipped.
ANZSES CONFERENCE - SOLAR'99
This years conference was attended by Kali and James from Flowtrack. There was NO representation of small wind turbines, and only Vestas from the big machines had a trade display. The next years stand at Brisbane might be an excellent place to display the current state of the Flowtrack turbine design.
The format of the conference was changed from previous structures to reduce the number of parallel sessions. The status of the poster presentations was improved with the presenters having a programmed five minutes to give a spiel. The break coffee was cunningly served in the room with the posters!!
This seemed a good idea, leaving time availiable for many plenary talks which perhaps did not warrant the time allocated to them! We did get a chance to personally question Meg Lees, and see some presentations from foreign experts from China, Denmark, and Britain.
From our point of view the venue was disappointing, with bad audio visual gear, patchy food, and building noise interferring with some important poster sessions. High points of the conference we judged to be some of the "panel" sessions of poster presenters. The time availiable for questions allowed some in depth "to and fro" to be allowed by the chair.
An interesting competetion was on between the various solar thermal technologies. Apart from an amusing presentation by Solarhart on how to manage investment partners, there were presentations on big dish, trough collectors and "submersible" collectors, all with the object of producing steam.
There is obvious economics in adding the output of these solar thermal collectors directly into a fossil fuelled power station as the turbine and electrical infrastructure does not need to be duplicated and undeniable carbon savings can be realised. There is however a problem calculating exactly how much carbon is saved when the thermal cycle is analysed, and an even bigger problem perhaps in convincing the consumer that this is really "green" power, sharing as it does a turbine as well as transmission system with the enemy!
THE NEW CHINA AGRICULTURAL EXHIBITION
This week leading up to the 50 year celebrations in China is a trade exhibition at which Flowtrack is helping a consortium of companies run a stand incorporating the wind turbine. Kali from Flowtrack and Peter Headley from Energy Australia are currently putting up a wind turbine head at the stand in spite of logistic trials to do with blocking of parts of Bejing by work leading up to the October celebrations.
The Flowtrack turbine is taking a proud place between tractors, balers and poo seperators!
The technology transfer of our wind technology to China is proceeding. Two of the engineers from BEST Pty Ltd (partners in the project) have been in Shanghai and Beijing looking at factories undertaking the work. They have reported optimistically on the results of the mission.
Brian & Greg being shown around Shanghai
AUSTRALIAN WIND ENERGY CONFERENCE
For three days after 28/6/99 Newcastle University hosted the Australian Wind Energy Conference which was well attended. Details can be found on the Newcastle University Engineering Department, linked to this site.
The major issues tackled were to do with the politics and structure of the Australian energy industry, and how conducive it might become to wind energy in the light of the 2% renewables obligation that the Federal government has taken on. A new force in the Australian scene was REAP from Melbourne with already a contract to build fifty generators.
There was a hot sideline at the conference about small turbines like ours with several papers on stress analysis. Kali from Flowtrack read a paper on the pulsating stresses created in a 2 bladed machine while yawing and how this related to blade flapping stress multiplication. She pointed out that a shaft frequency stress on the blades from precession can lead to a blade frequency stress from the shaft! . (This paper is avaliable on this site.)
HANNOVER TRADE FAIR
The Hannover World Trade Fair was attended by James Fuller and Kali McLaughlin as assistants in the stand hired by Woods Electrics of Newcastle.
Jeff Linthorne, of Linthorne Electronic Agencies, was instrumental in our participation in the event, he being interested in the success of the MACS which was being launched as a product.
THE MACS (Mains A.C. Stabiliser)
This is a device for adjusting the mains voltage in areas with unstable mains power. It is a device being developed since 1992 by Woods Electric with considerable input from James Fuller in the design of the microprocessor coding and some other details of the power electronics. Like the Flowtrack PPT transformer it is a considerable mass of iron and copper with triacs as the controlling devices, in this case changing taps on the transformer rather than changing power factor as in the Flowtrack machine. (Email Woods Electric)
There was considerable interest in this device as the competition were of either mechanical switching or ferro-resonant principle and the MACS proved to be better in performance and lower priced than the competition. There was of course lots of competition with a square kilometer of fair at the Messe Gelende. The pavilion we were in had a short dimension span of 150 metres in a very elegant space frame.
THE BICYCLE COMPUTER
James stayed on in Germany and has already completed 5550 Km of a 6000Km bicycle tour of Europe. This must be the ultimate in teleworking as he is actually cutting code from time to time when not pedalling. He somewhat surprised some people at a microcomputer factory at Ahlem by turning up on their doorstep and buying the parts for a 1Kg computer to be kept in a Bicycle pannier. It is based on a PC 104 board with flashram rather than hard drive, and a 1/4 VGA LCD screen and a floppy drive like a laptop. The lot was assembled in the corner hardware store where the proprietor happened to be a computer mechanic - typical of Germany! We are awaiting with interest the first posting of code via a cybercafe computer floppy drive....
The wind turbine in South Australia with its now wooden blades is running OK again, and a major overhaul on the 8 year old Survivor at Rainbow Power Company has been completed. This machine is a Flowtrack/Survivor hybrid, (oh yes, and also has Toyota ball joints in the pivot arms!)
It had worn out its front bearing and prop hub after years of not getting enough oil to the top of the gearbox. We did not bother with oil analysis - it had the look of tomato sauce! We have gone back to good old grease for this bearing now. Alan McDougal gets credit for a very nice job of replicating the prop hub and fitting it to the shaft. There is an acceptance now that you cant just put up wind machines and ignore them... regular checkovers are needed. There was nearly another disaster lowering the machine when the back cable broke a metre from the ground! The cause, for the record, was that the cable where it had been sitting in a cast iron pulley had had its zinc stripped as a sacrificial anode. The ensuing rust was not obvious, being inside the sheave. This is yet another way a wind machine can fall down. Are there fifty ways?
An antique (fifty years old) machine has been repaired and is running again. It is a Dunlite L 1000 and is an inspiration from the engineering of wind electric systems in the era before semiconductors! Several parts had disappeared over the years, including a handbrake hinge and a governing flyball. There have been rural myths about the machine making a loud bang and then stopping.....
ABN 68 079 207 168
0266 891431 (a/h)
0266 890408 (b/h)
OFFICE: End of Tuntable
Falls Road, NIMBIN