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Forum Index : Windmills : Whats the best F&P config for slow speed
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| hoggie Newbie  Joined: 11/06/2010 Location: Posts: 8 |
Hi Everybody Im planning on building a vertical axis mill with straight blades. My basic configuration will be 3 blades Naca 4415 or 0018 profile and approx 1.2m long and 1.4 meter diameter. Im hoping to achieve a TSR of 2.5-3 depending on soldidity,loading, blade profile etc. Questions are lots... Whats the best F&P configuration for slow rpm generation? At 6m/s wind speed im hoping for approx 200rpm At 10m/s wind speed im hoping for 320rpm Are there any better cheap and plentiful motors out there that can be adapted relatively simply? At the moment ive got now way of using the power that might possibly be generaated so am open to suggestions on that. The mill will be in my mates top paddock away from the house so its possible mabey just have a load dump.ie lights for the sheep or warmer drinking water for them?? This would mean no voltage control nessisary?? Ive read quite a few of the threads on this site and its seems all really good stuff. Just an awfull lot of things to think about. Any shared thoughts on any of this would be great!! steve |
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MacGyver Guru  Joined: 12/05/2009 Location: United StatesPosts: 1329 |
hoggie Do yourself a favor and consider switching to a HAWT (horizontal-axis wind turbine). The VAWTs are a pain in the drain; hard to balance, cumbersome, low (make that almost NO) power, etc. The only one (VAWT) I've ever seen that worked anywhere close to well was the "Miller Rotor". Do a search on the 4m here and read up on it before you start your build. There were even some youtube videos thrown up showing one of them twisting in the wind atop someone's garage. It's rather easy to construct and balance and seemed to put out quite a bit of power for its simplicity. That's my take on it. I've likely built them all and have come to the conclusion that the HAWTs are king. . . . . . Mac Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Hi Steve, Welcome to the forum. I know you Kiwi's love your sheep, but dont you think building a windmill to.... [quote]lights for the sheep or warmer drinking water for them?? [/quote] Is a little to telling you are a Kiwi. 
You have not given an system voltage for your configuration question so I take it you are asking what will give the best result for the rpm. Meaning best voltage for what stator configuration, and understand you are using a 80 series stator. I will let the experts answer this. Pete. Sometimes it just works |
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| hoggie Newbie Joined: 11/06/2010 Location: Posts: 8 |
Hi guys Thanks for the reply's Year i've got a 80 series stator and presumably cos im only going to be spinning slow ish ill be wanting to go for a low voltage system 12v? But because this thing hasn't been built yet except for the first set of trial blades and some of the central hub assembly.And there is no system yet. Is there any easy way of matching rpm voltage and load if your just dumping the little power that this thing might make into a resistive load? Maybe a picaxe micro that monitored wind speed and power output and turned on different light bulbs. Or some (rather large) project scope creep. A wind and solar battery charging system that might power a wireless IP web cam that can connect to my friends LAN and then the internet so i could monitor via the web cam whats going on? Probably want to also datalog results as im keen to try a few different Blade profiles,rotor diameter,solidity combination's. Wont need to much power for this so maybe the vawt will be all right. Steve |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5124 |
Hi Steve I did play around with a Lenz VAWT a couple of years ago. Direct drive into a F&P. 
From memory, I think a 80 series reached cut in on a 12v system at about 60rpm. It never went above 50 watts I think. If you just want to trickle charge a battery, then a 80 or 60 series on a VAWT would be ok. It would make good use of low and turbulent winds. But if you want to get more than a couple of amps, you need to look at building a HAWT as Mac suggested. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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KarlJ Guru Joined: 19/05/2008 Location: AustraliaPosts: 1178 |
Geez Gizmo the 50W wouldnt even pay for the paint job on that sucker! make it about 10X bigger for 500W perhaps.... mmmm engineering challenges! Luck favours the well prepared |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Gee Karl you are getting slack with no stator rewire advice here. I would have thought it was a question with Karl written all over it. It might pay to aim for 12 0r 24 volt because 48v or higher can give a nasty shock if grounded. You would not want your wooly blankets electricfied if you have a fault. The only problem with using lighting as a resistive dump load, is if the wind blows hard and the voltage increases it could blow the globe and then you have no control over the mill what so ever. I would urge you to think towards some form of a controller to dump to a secondary load should the voltage get to high. The opamp controller that Gizmo done (listed in the front pages) could be a good starting point and its a simple controller that works well. What sort of distance will this be located from your friends dwelling. The reason i ask is for wireless transmittion of data. Pete. Sometimes it just works |
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| hoggie Newbie Joined: 11/06/2010 Location: Posts: 8 |
so it looks as though ill go 12v system voltage. 80 series stator half series half parallel? And ill read up on Gizmo's controller right after posting this. I think line of sight from house to proposed turbine location will be about 75 meters. Hopefully this will be in the realms of Wi FI if not then a stand alone data logger will be employed. Cheers Steve |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
75 meters is a fair distance to send reliable wireless data without getting into a hight cost bracket of transmitters and receiviers. I would think you will need some sort of battery to power the mill end electronics, although it can be small. This will then require a controller of some sort to shunt the power to a dump load once the battery is charged. How do you intend to gather the data and use it with Wi Fi? Pete. Sometimes it just works |
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| Smart Drives Senior Member  Joined: 06/07/2009 Location: AustraliaPosts: 115 |
If you want any sought of decent amperage flowing 75m you are going to have to go 48v, Kiss 12 volts goodbye and think seriously about buying some thick wire for 24v. Which at 75m is not cheap (TRUST ME i did it). Then think about if you want to put up a second turbine later, if there is a small chance of this happening definately go 48v and save yourself a LOT of money later. Cam. All smart drive parts sold Custom built turbine parts on Multicam flatbed CNC Router |
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| hoggie Newbie Joined: 11/06/2010 Location: Posts: 8 |
At the moment im not intending to run the power to the house. This is just a fun learning exercise to see if i can make a VAWT make any power... Pete As far as data acquisition goes im still looking into various avenues. There's a Kramer box that converts serial RS232 into Ethernet which would then go to a wireless router. all powered by the mill and battery and possibly solar panel aswell.And ive got one of the kramer boxes at work which i could play with. Or just do stand alone data logging if the wireless Ethernet thing just gets to hard. Data log into Picaxe net server?into wireless router? There is also some very nice data logging/data acquisition boxes out there that are wireless ethernet.But these are well out of my hobby budget until i win lotto. Approx $1000 -1500 USD Ive read the op amp hardware controller pages on the main site and think ill build one of them.Well within the realms of my limited electronics experience and with the good instructions. I guess ill also need to build a dump load. |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Hi Steve, Yes the build list of things needed with a windmill keeps getting longer when you look fully into it, but thats half the fun and if you start to get your mind around whats needed, then its not so bad as there is always another little project to go on with while you are held up with something else. The worst is when you finish the windmill to find you need all the extras before you can cut it loose to mother nature. Considering this mill will likely make 2/5 of ff...flipping nothing in power being a Vawt i would say stick with 12 volt to keep the cost of batteries and other stuff down. Im sure you will venture to a Hawt later and then worry about higher voltages and whats needed to accommondate them. If it was me i would just stick a data logger on the mill and a cheap set of 433mhz transmitter and receiver modules (from Jaycar) and see if you can get the distance with wireless data to the house then feed the data to a PC or wireless router. I would thing keeping the mill end electronics to the very least required would be the most reliable and worry about the trick stuff in house. The data logger boards i designed has a spot allowed on the board for the 433mhz transmitter so it would be easy to just fit the module and see if you get the distance. (just a program change needed to send the data to transmitter rather than serial.) Pete. Sometimes it just works |
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| hoggie Newbie Joined: 11/06/2010 Location: Posts: 8 |
Pete Im liking your idea of cheap jaycar wireless Tx Rx set.And your logging board. Just wondering what id need at the output of the receiver? Ie how would it then get into pc? Through the serial port some how im guessing? Steve |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Steve, You need a 08m each end, one reading the mill data and firing it out the TX and one at the PC end reading the data from the RX and sending it out the serial port to the PC. All very simple and the code is also very simple. Or you could go to a higher level and use tranceivers as some come with the RX units able to plug directly into the serial port (and there is usb ones too) but the price jumps up quickly but so dose the quality. I like the fun in building and getting stuff working, with the knowladge gained along the way rather than off the shelf items that might do the job Pete. Sometimes it just works |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Steve, For interest the data string that gets sent via serial to PC for Piclog or Gordons windmill analyzer if written in code like this [code] sertxd("[<V>" ,#volt, "</V> <I>", #Amp ,"</I> <R>" ,#RPM, "</R> <S>",#Wind, "</S> <C>",#Check,"</C>]",13,10) [/code] The logging programs look for the identifiers in the string and put the data in between them in the correct files. So all you need to do is read in, lets say volts and store it in the picaxe variable labelled "volt" and the same for "amp", "rpm", "wind" and "check" is just all the values of the others added together and sent as a checksum, to check if the data was corrupted or not. Like i said all very simple. All the heavy lifting side is done in the PC software. Pete. Sometimes it just works |
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| hoggie Newbie Joined: 11/06/2010 Location: Posts: 8 |
Pete What distance do you think the jaycar rf units might be good for? |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Steve, Thats a bit of a hard question as it depends of several factors. You mensioned line of sight above if its a clear line than thats an advantage. The antenna style will have some impact as well. What the house is made from and where in the house the receiver is. I have tested a module by walking down the street and could get a link up to around 100m but to get good data transfer over this distance i dont know. It would be worth having a go with a set as they are fun modules to play with and very simple to use. If they wont do the job i am sure you will find another use for them, like perhaps on an aneamometer or some other remote controlled gadget. My gut feeling is they should work for you but might need to be mounted up in the air on the TX end. Lets face it some needs to test the distance out for logging with these and why not you. I found a local supplier had some little 433mhz rubber ducky antennas cheap and used these on mine as they are easier to mount vertical and dont blow around in the wind like a length of wire will. I used some 50 ohm coax to run the antenna up a meter or so to get better signal strength. Pete. Sometimes it just works |
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| hoggie Newbie Joined: 11/06/2010 Location: Posts: 8 |
Pete Just to make sure im on the same wavelength..haha Are these the jaycar items Transmitter Module: ZW-3100 Receiver Module: ZW-3102 Im guessing i'll have to put an external ariel on the shed were my logging pc is going to be housed as thats clad in steel.Although its only 0.4mm thick. And i can put the Tx ariel 3/4 up the windmill mast. or will that be a bad spot due to the closeness of the alternater generating that wild ac? Steve |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Yes they are the RX and TX i was meaning ( you could have given me a page number as i spent 15 mins finding them) 
Yes i would go for the outside mount of the ariel and doubt the wild ac will hinder things, although you want to be off the pole some as metal things close will hinder the signal. You say a shed? so mounted on a light pole above the shed should be fine. You dont want the coax run to long if you can help it. As for being on the same wavelength that would be 433.4mhz....Roger. Over and out.............. Pete. Sometimes it just works |
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