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Forum Index : Windmills : tower top control
| Author | Message | ||||
| brucedownunder2 Guru  Joined: 14/09/2005 Location: AustraliaPosts: 1548 |
OK,, I'm fairly handy with tools --but need some assistance with a very important bit of control gear.. This is my tower -top disc brake . It needs a remote controlled (maybe a tacho-controlled) bit of electronics that can be operated about 100 Meters remotely. 
I'm working 48v Exmork 2-3 Kw wind gennie --13 foot dia blades -- I have lots of cable and lots of electronic gear -67 yo retired communications guy , but the stuff in me head is dying fast.. Thanks Bruce. Bushboy |
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Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Wireless remotes and rotating metal makes for a poor signal communications and reliability (likely failure when most needed) this is why we developed the IR slipring method for use with Phills new controller to monitor stator temp and have a way to send the data down from the naccell without the need to add extra physical sliprings. If you are not using sliprings than a drop wire down the tower can be used with a wireless module located away from large fixed or moving metal mass. I still think electronic braking is as good as option as mechanical braking, if set up correctly. Pete. Sometimes it just works |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
I might bump this into the Windmill section, as I think it will be more mechanical than eletronic. I can think of several ways to mechanically brake a turbine automatically. For RPM a centrifical clutch could be used, and for wind speed a paddle in the air stream can be linked to a brake, but there is a common problem, heat and wear. If its blowing a gale and the brakes start to come into play, they will be working constantly, creating heat, which isn't a big problem. But the wear of the brake pad material will be. For something like your disc brake Bruce I would run a brake cable down the middle of the tower so you can operate it at the ground, or some distance away. That way you could manually slow down the turbine and lock it so it cant start back up. Trying to add some sort of electronic system to a caliper based disk brake would be a real challenge. What about a electric brake, like used on a trailer? Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| brucedownunder2 Guru Joined: 14/09/2005 Location: AustraliaPosts: 1548 |
Yes, Glenn. I tried the "fishing line down the tower" from the brake handle some time back --it worked,, was a deep sea fishing line ,,would take a lot to break it. But, hey, the experiment was successful, she pulled a screaming mill to a stop fairly quickly.. Apologies to Phill for my "spit" --hard day at the office-- he's doing some good work,,hope he still talks to me?.. The office----- I'm building in under the house a "clean" area.. I'm sick of the westerlies and wet damp on my toys. I'll keep an area for the welder,grinding,painting,drilling and other rough work. I hope to bring that disc brake out of it's coffin one day and fit it to the exmork. Would still like a electro-mechanical fitting at the top to activate the master cylinder(have all the bits).. Any help will be appreciated.. Bruce. Bushboy |
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| brucedownunder2 Guru Joined: 14/09/2005 Location: AustraliaPosts: 1548 |
don't know ,, but maybe Glenn, you can shift this into Phill's thread (if he agree's) .. It's sort of related ,,, Anyhow, I'm interested in comments or suggestions about building a faily simple electronic /mechanical push/pull master cylinder device to control the disc brake . I've got the hydraulic (sp) fittings and master cylinder off a motorcycle disc brake installation. I'm thinking ,I just need the remote control to operate this plunger and release it ... probably only 25mm or so .. About Pete's comment about revving metalwork up the top ,,, well, Pete, every car in the world uses disc brakes ,and every wind gennie I've seen uses a huge disc brake to control the rpm--..think about that!!. not trying to stir up an ants nest ,,, but this is my way of reply --please see if you can accept . Bruce Bushboy |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
I think what Pete was saying is the revolving metal work plays havoc with wireless communication, thats why he went to infra-red. The problem I see with the disc brake is they need a lot of pressure, compared to drum brakes or band brakes. The electronics to measure RPM and switch something on at certains RPM's is easy, its the actuator thats going to be hard. Drum brakes or band brakes have this little feature in that the shoe/band can bite into the drum, providing the rotation is in the correct direction. A little pressure on the shoe/band, and friction takes over to help pull the shoe/band tighter. Thats why old cars with drum brakes generally dont have a brake vacuum booster, but as soon as manufacturers brought out disk brakes, they needed to add a booster or the pedal was too hard to operate. Trust me, once the brake booster on my old Monaro sprung a vacuum leak and I had to use both legs on the pedal to pull up the car! Of course there are advantages to disc brakes, like better smoother control with less fade, but for a windmill we dont need that. For your windmill Bruce I would go for a drum brake, simply because its going to be easier to control ( with a electromagnet pulling on a band maybe ), or a electric brake setup. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Glenn is correct about my comment. @Bruce, before you go off half cocked about a comment, you should read the full comment, as i would have thought this would have been clear to what the comment related to and in hand with the question you had asked advice about. [quote]Wireless remotes and rotating metal makes for a poor signal communications and reliability [/quote] Your request for help is very unclear to what you would like to do, and how you intend to control the braking system, but you had requested the ability to operate it remotely, from this i guessed you wanted some form of wireless remote, and hence my comment. The comment you seem to have focused on.......... [quote]I still think electronic braking is as good as option as mechanical braking, if set up correctly. [/quote] Is because i have recently designed a electronic braking system for 2kw mills that has gone into commercial production for a company (they own the rights to the design) So i know electronic braking will work without the need for all the extra mass and mechanics mounted to the top of the mill. My point of view is i dont care how you choose to apply braking to the mill, but was offering advice as a alternative to your approach of solving a problem and to the question you had asked.. Pete. Sometimes it just works |
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| brucedownunder2 Guru Joined: 14/09/2005 Location: AustraliaPosts: 1548 |
Looks like I've been bashed up on this one ---- Anyhow, I'm happy in my block , it was just a simple question foofhead Bruce.. Bushboy |
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Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
For what it is worth, disc brakes for boat trailers normally have mechanical calipers operated by a cable rather than hydraulics. They are used as less problems with corrosion but also would be simpler to activate. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
Hi All, I think semi trailer airbrakes have a lot of potential. the parts are very cheap new and I imagine that replaced parts with small amounts of wear could be had for free. When I rebuild truck brakes it is easier and cheaper to replace everything than chance a defect notice. I have used the s-cam style brakes with actuators for some jobs and the original spring and air diaphragm setup for others. 
I'm confused, no wait... maybe I'm not... |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Maybe a mill tower somethink like this then 
Sometimes it just works |
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| yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
choice   I'm confused, no wait... maybe I'm not... |
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| windlight Guru Joined: 03/03/2007 Location: AustraliaPosts: 331 |
And I thought I was a grumpy old fart. "I like this place and willingly could waste my time in it" - (Act II, Scene IV). |
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| brucedownunder2 Guru Joined: 14/09/2005 Location: AustraliaPosts: 1548 |
Hi Alan ,,, No, you're OK ,,it's just me .. Been working on building in under the house lately ,so maybe a bit on edge at the end of the day -- .. But , I mean't nothing bad ,,us oldies just smell that way .. Hope you are enjoying the "dry" up your way , the westerlies at starting down here , so building in around my workshop will keep me happy. The solar tracker is sort of progressing slowly,will be able to mount the 900 watts of panels soon , then the big task of actuators and control .. Is Blondie back ? -- Take care buddy.. Bruce. Bushboy |
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| windlight Guru Joined: 03/03/2007 Location: AustraliaPosts: 331 |
Hi Bruce Blondie was back for about 2 weeks, it seemed like years, had to be here to collect her passport, she is taking a holiday. I hope you do not mean that you personally are going to mount the solar panels, hoping you mean to locate them on a mount. I have rejoined the work force for two days per week, can't say any more as this is so off topic that it will cause this post to be locked. Grumpy Allan in the Daintree "I like this place and willingly could waste my time in it" - (Act II, Scene IV). |
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rissole Newbie  Joined: 10/05/2011 Location: AustraliaPosts: 15 |
this may be of interest, it a new self contained electric/air/hydraulic unit that is normally mounted on the towbar and is operated by a variable voltage signal from the tow vehicle, it could be mounted up top and fed with a signal. check it out here; http://www.alko.com.au/uploads/2008/12/AL-KO-0033-Sensa-broc hure.pdf in a strange bit of Karma, the only one that I have seen was intalled on a trailer that we built at work to carry an access platform use to inspect the blades of wind turbines. Rusty |
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Don B Senior Member  Joined: 27/09/2008 Location: AustraliaPosts: 190 |
Hi Bruce, I am coming into this thread a bit late (as usual), but I wonder if the answer to the problem might be a centrifugal brake. If you have ever pulled a chain saw apart, you can see the principle in the centrifugal clutch that they use, where the clutch takes up under the action of centrifugal weights that rotate with the crank shaft. The weights are restrained by springs until the speed has built up sufficiently to engage the clutch. A centrifugal brake would have a fixed drum or disc, with the brake shoes rotating with the shaft. Ideally, the restraining springs (which also rotate) could be pre-tensioned through some sort of fixed collar and bearing, so that the cut-in speed of the brake could be adjusted from the ground, and could even be capable of locking hard on, if you want to immobilise the turbine. I don't have a diagram for you, and have never built one, but it should not be too hard to make for someone who is, as you say, handy with tools. The beauty of an arrangement like this is its simplicity. It actuates itself, and is fairly much fail safe. It is hence not subject to the sort of problems that could arise with failure of external electronic/air/hydraulic actuation or control systems. Just a thought. Regards Don B |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
I think a centrifugal brake left unattended in a strong wind is going to just drag and keep getting hotter until it wears out, unless you can get it to latch on fully. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| anteror Senior Member Joined: 06/10/2009 Location: FinlandPosts: 189 |
Chain saw brakes or other brakes in windpower.. 
I have Chinese made; http://www.huayaturbine.com/ for 4 years in my place on seashore. This windgenerator has seen numerous severe winter storms and harsh winter climate etc Tested 9 windgenerators to find REALLY special robust machine and cheap; http://translate.google.fi/translate?sl=fi&tl=en&js=n&prev=_ t&hl=fi&ie=UTF-8&layout=2&eotf=1&u=http%3A%2F%2Fwww.poikkis. net%2Findex.php%3Ftopic%3D5033.0&act=url Windgenerator must be made of cast iron and be heavy. Everything in windgenerator/windpower MUST be oversized X 2-3 to withstand all storms and weather conditions. Here in Finland we have very special and harsh climate. NO BRAKES ! Just special robust machine, to make power, in all conditions. Antero |
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