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Forum Index : Windmills : 3kW Generator Unit
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| Jason69 Newbie  Joined: 04/07/2007 Location: AustraliaPosts: 4 |
Hi All, I am interested in building a wind turbine that can provide a significant portion of my home electricity. I have a 3 phase SEW AC industrial motor and I was wondering if it was possible to use this as a generator, producing power directly to my meter, I'm not looking to produce stand alone electricity, more to "stop the meter" when it's blowing. I live by the coast in Sydney so we get a fairly consistant NE breeze in summer and SW in winter. I was thinking of a VAWT but seem to be reading a lot of negative stuff on the web. I'm totally new to wind turbines but my background is Mechanical Engineering, so I can do the mechanical side but the electrical stuff is way out of my comfort zone, so any info would be much appreciated. Cheers Jason |
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herbnz Senior Member  Joined: 18/02/2007 Location: New ZealandPosts: 258 |
Hi If you have 3 phase power you can use the motor with the blades mounted directly the rpm of the turbine will have to be designed for the motor rpm might be problem if 4 pole motor 1500rpm. you wire the motor as if its going to drive the mill. but arrange a control circuit that will only energise it when mill rotating faster or egual to motor rpm it will then feed into supply as a generator. As long as no capacitors are used if the power goes off the unit will stop generating so safety is inherint although mill will overspeed here. control is also needed to disconnect when wind dies and power is driving the motor a old power meter fitted with contacts can do this. Herb |
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| herbnz Senior Member Joined: 18/02/2007 Location: New ZealandPosts: 258 |
One more note your supply authority may not like you doing this |
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Highlander Senior Member Joined: 03/10/2006 Location: AustraliaPosts: 266 |
Hi Jason, unless you have a permanent magnet motor it will not produce electricity. It sounds like you have an induction motor. Can you post a picture of it? Secondly if you live in Sydney you may have a problem erecting a large tower to put it on, the neighbours and council may not like it. Thirdly connecting anything other than a grid interactive inverter to the mains is a big, big no no, even then it must be done by a sparky. Wind power(voltage) will vary with speed so you'll need to make dc power then store it and invert to ac for household use. If your in a built up area I suggest looking at an airx turbine, they are nice and small, but capable of 400 watts, they also have their own controller built in. If your on the grid it will always be cheaper using that. However if you want to do your bit for the environment then go for it. Or buy green power from the supplier.  Central Victorian highlands |
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| KiwiJohn Guru  Joined: 01/12/2005 Location: New ZealandPosts: 691 |
Now I am not saying that this information is definitely applicable but a basic induction motor can be used to "drive the meter backwards"! If I understand it correctly: Connecting the motor without load to the mains will cause the motor to run at its synchronised speed (or very slightly less), if you put a load on the motor more current flows and of course the meter runs faster, on the other hand if you have some drive (like your wind mill) that tries to drive the motor above it synchronised speed the reverse happens and as you might expect the meter runs in the other direction. It would appear that all that is required is the motor connected via a one way clutch to the windmill. When the wind drops the wind turbine slows and the clutch allows the motor to continue turning at its mains synched RPM, when the wind comes up again the clutch tries to drive the motor overspeed and the energy flows back into the mains grid. Get some real advice before trying it though!  |
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| dwyer Guru Joined: 19/09/2005 Location: AustraliaPosts: 574 |
Hi Jason Just be very carefull if anyone want to "drive the meter backward" and back to power line as any power worker who cut the power off just to repair powerline maybe new line wire,replace fautly cicuit beacker or transformer get unexpect electric shock from someone is asking for big trouble 
Dwyer the bushman |
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| Highlander Senior Member Joined: 03/10/2006 Location: AustraliaPosts: 266 |
Hi John, I don't get it mate. If you drive an induction motor do you produce electricity? Central Victorian highlands |
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| Jason69 Newbie Joined: 04/07/2007 Location: AustraliaPosts: 4 |
Hi John, What your talking about is exactly what I was thinking, and I think this is how all the large wind turbines operate. But that is where my knowledge of the subject stops. The advantage is you wouldn't get the problem Dwyer is talking about because if there is no mains power I can't produce any. What I really don't know is what I would need from a controls point of view from the motor to the meter. Highlander, the unit is an SEW DV100L4 they have alot of info on their website http://www.sew-eurodrive.com.au/produkt/A21.htm thanks for the info about the airx turbine but with a wife and two daughters I don't think 400 watts will put much of a dent in the overall consumption even after I have changed all the light globes.... The next thing is to speak to the local council as I'm thinking this sucker might be talking about a 4-5m diameter set of blades....... Cheers Jason |
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| Feral Newbie Joined: 03/12/2006 Location: AustraliaPosts: 39 |
Jason69, all the information you will require is at the site identified below. Read all of the articles posted by zubbly as he has come up with the convertion procedure for the three phase induction motors for use as wind generator. http://www.fieldlines.com/?op=search&offset=0&old_count=30&t ype=story§ion=&string=Zubbly&search=Search&count=30 |
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| KiwiJohn Guru Joined: 01/12/2005 Location: New ZealandPosts: 691 |
Highlander, the induction motor will only work as a generator if it is initially energised by running as a motor and I think you have to 'motor' it up to mains synch speed before applying the load. I think some vehicle dynos use this method too. Now I am off to read the link that Feral has provided! |
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| herbnz Senior Member Joined: 18/02/2007 Location: New ZealandPosts: 258 |
Hi All the control needed is a sensor for rpm hall effect controling a contactor to turn unit on when above sync speed (if using single phase can use internal switch ) then to turn off get a old power meter fit arm to disc that operates contacts on rotation connect both voltage coil and current coil to mill feed whill try to rotate one way when feeding other when being driven contacts disconnect when being driven. overspeed is a prob when mains power goes down either mill needs to allow for it or a braking system is fitted. Now I can not find link of Feral's but warning if any mention of using CAPACITORS TO EXCITE MOTOR DONT IN ANY WAY CONNECT TO THE MAINS THIS IS THE SITUATION THAT COULD ELECTROCUTE A LINESMAN. Induction motors can be self excited by capacitors and will work as generators a little unpertictable but many of the cheap portable generators do this ie the 650w chinese unit under various brand names does it works fine i have one here ( cost $25 US in China ) Herb |
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| Jason69 Newbie Joined: 04/07/2007 Location: AustraliaPosts: 4 |
Hi All, Have you guys seen this? from WA http://www.abc.net.au/news/stories/2007/06/27/1963676.htm http://www.wa.alp.org.au/news/0607/27-10.php |
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vasi Guru Joined: 23/03/2007 Location: RomaniaPosts: 1697 |
For the first link I think is a testing unit, without alternator. It looks like a modified version of Lenz turbine. If it was tested without alternator I think is not relevant. Of course, they can say: "the alternator is on other side". What you guys think about this: [quote] The West Australian Government is helping Mr Attey fund his TRIALS ... [/quote] I THINK IS NOT RIGHT. I think there must be a competition and the best design can win the funds. How many DIY-ers are around here with already great results? But I think is not my bussines. And is not a good design because it captures wind only from two directions. Or maybe Mr Attey want to put a pivot under that house ... I can say to Mr. Attey: you need also a furling system for that house  .
[quote] “Mr Attey’s design has considerable advantages over other residential systems that are being developed in other parts of the world,” Mr Carpenter said. [/quote] Really? How is that? ABBA had a song ... Hobbit name: Togo Toadfoot of Frogmorton Elvish name: Mablung Miriel Beyound Arduino Lang |
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| Jason69 Newbie Joined: 04/07/2007 Location: AustraliaPosts: 4 |
Thanks all for the info, I have found these guys in the US who have built a slightly larger (5.5kW)version of what I was planning, so I might buy their book and have a read, it looks a little "agricultural" but the controls side is what I was planning. http://www.prairieturbines.com/ Cheers, Jason |
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| vasi Guru Joined: 23/03/2007 Location: RomaniaPosts: 1697 |
And I saw a movie with Mr. Attey roof turbine in action: http://www.youtube.com/watch?v=WZ5kX5Yw4eY Very slow ... Hobbit name: Togo Toadfoot of Frogmorton Elvish name: Mablung Miriel Beyound Arduino Lang |
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| hoodlem Newbie Joined: 02/07/2008 Location: AustraliaPosts: 7 |
It will be a big sweep area for that sise turbine and heavy too, I will make power but only above the motors rated speed,when you spin it faster than rated speed you are pushing against the grids signwave thus the faster it spins the harder it pusher and the more power is produced but you cannot connect it directly to the grid unless you would like some big fines from the power authority. We would all like to do it the easy way but we have to use a grid tie inverter to feed back into the grid. free information for all |
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| Robb Senior Member Joined: 01/08/2007 Location: AustraliaPosts: 221 |
Yes! provided it has a voltage to excite it and you run it with slight negative slip. I'v done it as a test and yes the meter does spin backwards  . It was only for a brief test as there would be many issues of red tape to allow it to be perminant.
Probably best suited to hydro due to the requirment of constant RPM. |
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