The turbine's speed is held constant by being "inductively" locked to the 60hz grid. The shape of the blades results in no or very little increase in power output of the rotor with the increasing power in the wind after a certain point. However, there are limits. It it were forecast that prolonged very strong winds say in excess of 55mph, I would shut the turbine down rather than place it at risk. Even though our prototype has survived this wind on many occasions in reality if you could avoid that extra stress that's probably a better choice.
(There are several ways to solve wind survivability problems. Rotor furling, blade pitch, or just shutting the turbine down at high wind speeds. Breezy 5.5 uses a forth method, brute strength. If you have been looking through the book/plans you may have picked up on this. This is probably the heaviest turbine of it's size out there.)
Question: Do you think I will be able to use the old windmill tower and install Breezy 5.5 up there?
If you are talking about the old water pumps, they are not strong enough to stand up to the pressure of an 18-foot rotor.
Example: old windmill with 6’rotor, 40mph wind.
Old windmill = 232.3 lbs of force
Breezy 5.5 = 2083.5 lbs of force
We seem to be getting a lot of questions about rotor blades: Are the blades difficult to make? Wouldn’t it be better to use a more efficient design? Is wood really a good choice? Do 4 blades in a rotor cause problems?
First of all, these blades are extremely easy to make when compared to others. It amounts to setting an angle on a handheld power planer, and making passes with it along the length of the blade. After you have planed the blades they must be sanded smooth and painted.
Blade efficiency is not a problem?This is where some of the older grid-tied asynchronous generators failed miserably. They spent a lot of effort in making highly engineered airfoils with controls that would correct the pitch with varying wind speeds. These controls were the doom of most of those designs. It really doesn’t matter how “high-tech” something is if it’s broke. The blades on Breezy 5.5 do their job extremely well. Having a 4-blade rotor Breezy 5.5 can generate power at wind speeds lower then any asynchronous machine out there. Breezy's rotor is specifically designed to operate between wind speeds up to 23mph and it must loose efficiency above 23mph or the generator will overheat. At low wind speeds power is all about blade surface area (mostly). At high wind speeds, if you are designing for that, it’s all about pitch control and blade profile. If your day in day out wind speeds are between 6 and 23 mph Breezy's blades will do a fine job for you.
Are wood blades a good choice?Wood is among some of the best materials when comparing fatigue properties. Wood was born to bend; it is not however without it’s limitations. The majority of builders are comfortable working with wood. Sure there are guys out there who are thinking carbon fiber, titanium, aluminum, or whatever, and that’s their choice. But for everyone else wood is an excellent material for blades, if properly finished and maintained they will last a very long time.
Do 4 blades in a rotor cause problems?I think most of the problems associated with four blade rotors resulted when they were used in downwind systems. The problems resulted from what is called shadow wake turbulence where the airflow had been disrupted or partially blocked by the tower. When the blades, being down wind, passed through this void or disrupted air the force that had been applied to it would momentarily be gone. Keep in mind that the opposite blade now at 12:00 position still has the full force of the wind against it. This imbalance of lift caused abnormal stress in the hub and yaw assemblies and led to premature failures. Breezy 5.5 being an upwind design is not affected by shadow wake turbulence.
It is easy to see however that vibration etc. in one blade could travel across the hub and be present in the opposite blade and that would be impossible if there were an odd number of blades. If that were a major problem we would not be able to use any rotors with an even number of blades and I suppose this would include aircraft. We do see a lot of planes and choppers with rotors and props having an even number of blades in them.
With all this to think about keep in mind, Breezy 5.5 rotor is not up there turning 500-600rpm. Our rotor and generator are locked to the line and geared so that the rotor speed is held at 120rpm. At 120rpm it isn't as critical that everything be perfect, that all blades match precisely, we do have some margin for error.
Q: 1. What would you estimate the total cost to build this project would be? 2. What motor/generator/alternator are you using? Thank You
Q: Hi will I learn in this book how to make a power generator using a regular 3 phase motor and how to
connect the power from my wind power generator to the electric gird? I know it says yes, but I want just make sure,
it seems very cheap price for all that information, if I will learn that I'll buy it for sure . THANKS, SO MUCH..
Q: Can I use this generator as a stand alone system? A:
A:T, this type of generator is termed asynchronous, which means that it requires an outside source to synchronize, ie. the AC line source (and may not be of direct relationship to the speed). If it were 50hz then in your case a 4-pole motor would sync slightly above 1500 rpm when used as a generator and still produce 50hz. These motors are the most common AC motors used today. The controller would require different parameters in the program but it's not a big concern. If you were to build a Breezy 5.5 and purchase the controller from us, we would alter the program for the UK for no additional cost.
Q:I'm a little fuzzy on what type of generated power your controller can tie to the grid. Does it need AC? What types of very small motors or generators can it work with?
A:The function of the controller is to: release the motor/generator brake, monitor motor/generator speed, connect the motor/generator to the line when the speed is correct, and disconnect the motor/generator when the wind dies down. The controller will also engage the brake and disconnect from the line if it detects an over-speed condition.
This controller was designed and programmed to work with induction motors (squirrel cage motors) having a nameplate rpm of 1725- 1750. However, we can change the program to operate with different speed motors. (Breezy 5.5 is designed to have a turbine rpm of 120-122)
Think of it this way: a 4-pole 60 HZ induction motor turning at 1799 RPM is a motor, a 4-pole 60 hz induction motor turning at 1801 RPM is a generator. It's that simple.
Could use a light composite to make the blades. Black in color to melt any snow accumulation. We have a factory that produces light weight composite if a mold is provided?
Sure. But it would be hard to beat the cost of a 2 x 12, $25 to $30.
However, it is your turbine.
A: Bosch model: 1594
Q:How is the work on your demo coming? I am still interested in seeing it run.
A: L, we have the demo-trailer nearly ready to operate at Derby. Check back in a couple weeks and we'll set up a time you can see and hear it run.
After running the demo trailer and evaluating the performance, I’ll say “the higher the better, at least 35’ above anything within 200’ of the turbine“.
Q: Hi what happens in northern climates with freezing rain or snow? M.
A:If you get ice on the blade you’ll want to shut it off until it’s melted. Might be a good idea to paint the blades a dark color so that they will absorb more heat to help melt the ice. If you live where the temperature drops below -22F you will not want to use the merc slip-ring assembly. Check updates.
Q: Would you have any info about 3-sided towers that breezy could be set up with? Thanks J.
A:We built a 3-legged tower 6 years ago for and old 25kw wind-turbine and used 4-inch oil well pipe and criss crossed it with 2-inch angle Iron. It was 127 feet tall and the base was 17 feet. We also just laid it down to retire. To much trouble to service (it took 4 hours). Breezy's tower takes less than 10 minutes to lay down. A 3-legged tower it is a lot more work to set it up and down. Also it takes a winch or a big tractor with at least a 4-sheave block system to raise and lower. You can build a guy wire tower for a fraction of the cost.
Q: I was wondering if there are any Breezy 5.5 up and flying that I might check out.
How long does it take to build Breezy 5.5? Alan completely rebuilt the prototype in 5 weeks (yes he also works a full time job). This included a new frame, hub, blades, tail, and support structure. He reused the control enclosure and components (motor, slip-rings, and such). Of course, he has done this before. J
Q:(B asked about swapping out a new 1000 watt Outback and placing Breezy on his tower, which cost him many times what would Breezy cost to build.)
A:B, Breezy 5.5 would make a great addition to what you have. The best thing, you are already set up to meter your excess. If it were me, I would build the 5500-watt Breezy and use it in conjunction with the 1000 watt. Breezy will provide the bulk of your day-in day-out power needs and in case of a long-term power failure (ice-storm etc.) the Outback would shine (providing you have battery storage). Unfortunately as for a swap-out, I doubt the support structure on your Outback would handle Breezy. You could compare the material sizes in the book with what you have now, but we are talking about a turbine over 5 times the size of the Outback.... If you talk to the power company be sure that you explain that Breezy 5.5 is an asynchronous, line excited, AC induction generator. Which means that it has to have their line to generate and therefore is synchronized to their line. Large 30kw to 100kw machines work exactly the same way...they shouldn’t have a problem with it.
many hours on your prototype to date?
A:The prototype has been running for 18 months in the final configuration. Nearly 3 years in a variety of configurations.
Q:Do you use slip ring or cable twist at the yaw bearing?
A:We use Mercotac 830. However it is not suited for temperatures below -22
We are currently working with a manufacturer to source a traditional slip-ring for use in cold climates. (Cable twist at the yaw could be used, but it is a much larger source of failure then a slip-ring assembly)
Q:Is the motor brake electrically activated or electrically released (in other words, if there is a grid power failure, do you lose brake function)?
A:The brake is electrically released. If the power fails the brake is set and the turbine will stop.
Q:Is this a furling design or do the blades stay oriented to wind? What is the strongest wind encountered so far on your prototype?
Thanks in advance. K. M
A:This blade design has a lot of drag at high wind speeds. Since the generator operates at a near constant speed once on-line, drag in the blades helps to control the output of the generator, by not over powering it at high wind speeds but also creating a lot of lift at low wind speeds. Proty (the prototype) has been through several storms which have produced straight-line wind gusts. The generator stayed on-line generating throughout the storms.
Q:Could send me some more details on the parts I need to buy,other than the controller I need to get from you? I would like to come by and look at the one you have,so I need your address and a good time to come by. Thank you C.
A: Major parts to purchase: motor/generator, torque limiter, slip-ring assembly, bearings, relays, small 30amp breaker/box, run capacitors, and wire. These are the components you probably don’t have lying about.
Q:Hi, I would be curious as to the total cost of grid tie inverter and everything associated with grid tie. It is my understanding most power companies frown on grid tie systems and some make it very difficult to access. Most off grid people I've talk to all say don’t waste your time with grid tie, its not worth the hoops and payback time is very lengthy.
Is this generator capable of 60hz at all ranges? Whether its 8 mph or 30 mph?.. Thanks..S
A :Breezy 5.5 requires no inverters or battery's. It locks on the grid with the 60 Hz. This is how 95% on the big turbines work and a lot of them are putting out 300+ kw.
We agree with you that wind chargers that require grid tie inverters are not cost effective. A grid tie inverter for 5.5 kW DC machines would cost over $5000. Breezy 5.5 is an AC generator and can be built for less than the cost of an inverter. This turbine is not made for off the grid. Breezy 5.5 does not care if the wind is blowing 8 MPH or 30MPH, the turbines still turns 120rpm. And still puts out 60hz AC (it just puts out more power at 30mph wind).
Thanks for the information! You have some great suggestions! I think your invention is amazing. You two should be very proud. Think what our society would be like if every home had a Breezy 5.5! Thanks again! - M.
Thanks M. but I suppose we should give some of the credit to Nikola Tesla who actually invented this technology over 125 years ago. We’ve just taken a little different approach to induction-grid-tied wind turbine technology.
Q: How long have you been working on this project? how long has the 5.5 unit in the picture been flying. I am very interested in getting a grid tie-in and I would also love to hear of your dealing with the local electric company. Sorry to ask so many questions but I have been burned before buying plans online, though I must admit I am almost ready. I just need some info on exactly how I can gridtie (from my own local E company) and the track record of mill in question. Dose anyone know how many of theses 5.5 units have been built and where they might be found churning out the sweet clean juice. Thanks, G.
A: G, you'll have to check with your power company to get their connection "standards". The book has a copy of general standards for a company using detent metering. We've gotten a pretty mixed bag of reports back from people who have contacted their local power companies. It seems like the larger the power company the more positive the response. Some of the smaller companies do not have a clue as to what asynchronous generation is or how it works. One company required that the generator complied with a UL code that was for an inverter, saying that if it didn't have that particular code stamped on the controller it wouldn't be accepted for connection to their circuits. They must have took the matter up to higher management and at some point later stated that have to test the generator to make sure that it was an asynchronous generator and that it wouldn't degrade the quality of the power in their circuits. Most states have a renewable energy policy and have mandated that a certain percent of all power come from green energy. I must say that all contacts that I have personally had with my power company have gone smoothly. One other thing on power companies, I have not heard any reports back from anyone saying that a power company has outright refused to allow one of these generators on their grid.
Local building codes? Now that's another mater all together. The set I hear the most are: maximum height 100', must be 200' from residence, and must be set back from property line 2 times the height of the tallest point on the turbine. There are places that have no building codes at all concerning generator and structures. Check locally. Until Breezy 5.5 there just was not much out there on homebuilt induction generators. We spent 3 years getting it right or very close. The prototype which is pictured on our website is our original generator. I will tell it has been through hell. In the final configuration it has run about a year and a half. It has been through several storms, which produced straight-line winds in excess of 70mph in which it remained on-line and generating. The structure, yaw assembly, and frame of this generator are heavier than the 25Kw Carter, which sits to the west at the same site as the prototype. We used the big Carter for a platform in which to design Breezy and made it stronger and more reliable. Tim
G, you ask how many of these are up and running? There are just two, the prototype and the unit on the demo-trailer. However, it won't be long until these start popping up all over. We've sold the book/plans in seven countries now (consider it was published only three months ago). Tim (by the e-mails we're getting and parts we're selling, I would say that there are now at least a dozen under construction) (8-27-06, 4 operational units)