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Forum Index : Windmills : To Slipring or Not to Slipring
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Grandpa Newbie  Joined: 22/01/2012 Location: AustraliaPosts: 4 |
Just possibly this is a old post, but being a newbie, I missed it, unless someone can point me to it: So My question is after looking at lots of other areas, even youtube, there seems to be a balanced view for and against the use of sliprings, In fact one valid thought was; That sliprings are just another thing to go wrong, along with the other that your cables get tangled up, as well aslso slip rings limit what you can really do, I suppose without outlaying big bucks for multi pole slip rings, they do. So surely the wind does not have a set pattern; that, assures you of this tangle problem,, by progressing around in one circular motion ? I can understand over time they could become tangled, So untangle them. In fact this system must be excepted as not everyone is using sliprings. My benefits of not having a slipring, allows for more cables, which would allow me to install one or two stepper motors, (for an idea I have along with a cable for Electric break .) I am looking at having a stepper motor, to reset the wind-mill, to a neutral position after two revolutions either way. Also a stepper or small gear motor to allow me to electrically furl the mill or even lock it with a solenoid. Also another thought I have is using air, which can be pumped by hand, to operate rams. At the head once again, for furling and breaking. I also want a six core from the mill so I have the option at base of a star or delta, electrically controlled at the base. For apparently once again there are also two schools of thought on star and delta, what better place to test this theory than in the field, not on some work bench. So really I want more cables at the head So how about some brain storming. It doesn’t matter if someone has failed in this idea, or some of the ideas, are frowned upon, Just maybe other where not aware that there is no rigged set rules how you build your wind-mill , and just maybe others would have approached other people’s ideas differently, with a totally different outcome: For as far as I can see there is no bible for Wind-Mills. The point is to step outside the box, all great ideas only come from stepping outside the box. Not tunnel vision. Some ideas may seem foolish to start with, but with different approaches, and input from others, just maybe it will work, and work well. Unless to try, you will never know. All that is required is to pull your finger out and have ago. Grandpa. “Destiny comes to those who listen, and Fate finds the rest. So learn what you can learn, Do what you can do, and never give up hope!” |
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norcold Guru  Joined: 06/02/2011 Location: AustraliaPosts: 670 |
Have two OEM`s with sliprings, also an old(5 years service) 200w mill no sliprings just untangle at base of tower now and again, no drama really. If you search the 4M you`ll find Bob uses a bungee cord. We come from the land downunder. Vic |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Grandpa A picture of my old mill that Vic mentions the bungee allows 2 turns in each direction until it winds up and springs back to a neutral point. 
The bungee has been on there for 3 years now and still ok, it's marine rigging bungee so it is UV protected. All the best Bob Foolin Around |
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| Barry T Coles Senior Member  Joined: 30/07/2009 Location: AustraliaPosts: 109 |
You could simply weld a stopper at the top of the mast & a pin on the genny that way the genny will only rotate about 358 deg. Cheers Barry I need to learn from the mistakes of others. I dont have the time to make them all myself. |
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| Grandpa Newbie Joined: 22/01/2012 Location: AustraliaPosts: 4 |
Excellent idea Bob. So, I will scrap my idea to use a motor to reset it the mill, (Mechanical, usually is Fool proof), Plus you can also see it working. But I still want an Electrical or Mechanical brake, I was thinking of a Centrifugal Brake, can also act as a counter weight to blade, I have worked with Centrifugal Brakes quite lot in the lift, winch and windlass, also the crane industry, most used as fail safe devices, quite simple, I have seen a lot work also. There are mechanic ones, and others I have worked with where electrically assisted, in fact the clutch of a car-Air Con, compressor, could also be adapted I most certainly will not be relying on shorting the fields out to stop the unit. As I am a great believer in murphies law. So; I have a simple system that has worked all my working life: Particularly through my business, I always build in redundancy: my major principle was: Never run a machine or design a machine to run at 100%; I always recommended, from a 50% to a Minimum of 20% Redundancy. (I may not have won many quotes, But I never had to advertise and I was worked off my feet) Most of my return work where to people that did not heed that advice. Sometimes trying to save a dollar cost two. Never put a machine under undue stress, always have safety items in place to protect. Things do go wrong. Also most important periodical maintenance. I have never designed anything that cannot be easily maintained, mostly because it has to last. So My mills won’t be going up till I have looked at all options, A Thought that did come to mind, has anyone played with four, five or six phase units. Sometimes referred to as multiphase motors, the six phase is quite common, in many automated areas. Grandpa “Destiny comes to those who listen, and Fate finds the rest. So learn what you can learn, Do what you can do, and never give up hope!” |
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| Grandpa Newbie Joined: 22/01/2012 Location: AustraliaPosts: 4 |
I did give that a thought: but when you think of the pin, and the stop, you will lose at least 5 to 10 deg, That’s may not sound much, but when you run those two points out from the mast 100mts, that’s a lot of area you have lost. Also it gets greater the further you go. I really want my 360deg Grandpa. “Destiny comes to those who listen, and Fate finds the rest. So learn what you can learn, Do what you can do, and never give up hope!” |
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| Air Bender Senior Member Joined: 25/01/2011 Location: AustraliaPosts: 206 |
Hi Grandpa, When it comes it comes to sliprings i think it depends on the location of your mill. Some locations will have wind coming from the same direction day in day out, while others like mine will have a 360 deg rotation nearly every day and sometimes more than one. I think this plays a big part in choosing to go with sliprings or not. I made some sliprings for the small hawt very cheaply that have worked without a fault so far. It can be done. All the best Dean. |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Yeah I agree with the comments above. It does depend a lot on the conditions and location. I've used both, but I prefer to not use slip rings, only because I dont feel I could make a set thats good enough for the job. On my tower I ran the power cable down the center, and it had a plug at the bottom, so I could unplug it and untwist the cable as needed, once every week or so. But I didn't get many wind changes. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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Don B Senior Member Joined: 27/09/2008 Location: AustraliaPosts: 190 |
Hi Grandpa, Unless your wind pattern is a daily rotation, you are better off not using slip rings. The alternative is to set your cables up so that they can accept the maximum of twist (eg hanging vertically through the pivot down to the ground). One option is certainly a bungee system that will unwind the wind up after the wind drops. Another is a long light line from the tail secured at the base of the tower made long enough so that it can wrap itself around the tower as the tail pivots. This will track whether you have a consistent clockwise or anticlockwise rotation. Maybe you can use both. If you are able to keep a reasonably regular check on the rig, then you can use the cord to walk the tail around to unwind the wrap during light wind periods. Note that there will be probably about half a volt drop across each slip ring, so that there will be a power loss associated with the use of slip rings. This will be of greater consequence with lower voltage and hence higher current systems (ie 12 Volt). As you also note, using slip rings limits your connection options, and also tends to channel greater currents through the sliprings due to the lesser number of conductors that you can practically provide slip rings for. Having slip rings also limits your options for control (eg brake) and instrumentation cabling. Regards Don B |
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| Grandpa Newbie Joined: 22/01/2012 Location: AustraliaPosts: 4 |
Thanks Don. Matter settled: No slipring: I realy was not in favour of them anyway, your answer has finaly settled my mind, however it also have given me another thought. whether to; bother with these OEM's wind turbines; or not, I don’t really have much faith in them, a closer examination of them, really shows them for what they are, cheap crap; So might look into designing a Multi phase unit. Also thinking more along the lines of a vertical axis. Will let you know how I go. I have plenty of time. The solar panels are keeping up with what I need. So Wind will become a hobby. Grandpa. “Destiny comes to those who listen, and Fate finds the rest. So learn what you can learn, Do what you can do, and never give up hope!” |
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Andy R. Newbie Joined: 07/05/2010 Location: United StatesPosts: 18 |
I've used a "stop chain". About one every week or 2 if the mill would quit turning in decent wind, I'd go out with a long pole and turn the tail around and unrap the chain and then it would start right up. I'd usually set it to 2 or 2 1/2 turns before it would stop. I often thought about an "elastic chain". Bungee cord sounds good. Thanks Bob.  |
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| Don B Senior Member Joined: 27/09/2008 Location: AustraliaPosts: 190 |
Hi again Grandpa, One further thought on this matter which depends on how your tower is set up is to use 2 or more cables in your drop, and fix them to a weight at the lower end. If the weight is free to lift, but not free to turn, then, as the wind direction changes, the cables will twist and lift the weight. In light wind periods, the weight will drop and cause the cables to rotate the head and remove some, at least, of the twist. This scheme relies on having a reasonably low friction bearing at the head, and is maybe nothing more than a good theory, but perhaps it is worth a try. It is also worth remembering that constant flexing work hardens copper, so that it is always better to have many strands of small diameter copper in your cables than few thick ones. Despite that, I am sure that any cables that you can lay your hands on that have a reasonable copper area will be more than satisfactory. Regards Don B |
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vawtwindy Newbie Joined: 23/10/2010 Location: IndiaPosts: 31 |
Is that the bungee an elastic material? I thought of using a old cycle Unused tube in thin format, would'nt that help? |
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