Tuesday, May 14, 2019

Active YAW 2.0 KidWind Challenge

Last week I posted my first design of a KidWind turbine YAW using a tail to achieve upwind passive yaw modified to make it a motor driven Active up wind YAW like the commercial grade units.

To the left is my improved 2.0 design. To the right you can see that the YAW with a tail required the tail to be attached to the 1 - 1/4" PVC pipe that rotated around the center 1" PVC pipe that the nacelle was attached to in last weeks post.

The key is this. Mounting the 32 tooth KidWind ring gear to a 1 - 1/4" center post and fixing it to the top of the pipe (turbine tower in the real world). This is trickier than it looks. Getting the pieces  concentric and getting enough thickness to hold threads for the set screws.

And the whole package (Nacelle in the real world) sits right on top of the tower just like this. Looks like a nice opportunity to bring in a new technology, fiberglass, and the design and construction of a shell to cover all this and protect it from the weather and birds! Maybe even some sponsor advertising!

So the top is pretty much the same with the limit switches and control vane that senses the direction of the wind. But, attached to the bottom side of this board are the relays and battery to power the system (seen in the picture above this one).

Another key to the design is that the plate that holds the drive motors is fastened to the 1" PVC that goes down inside the 1 -1/4" pipe (tower). The plate sits on and rotates on a thrust needle bearing. When the signal comes from the wind vane the motors turn the pinion gears either CW or CCW to turn the Nacelle and blades to point into the wind. Two motors also act as a brake when not powered.

As a bonus I put a piece of elastic on the bottom back to hold the Vernier GO Direct Energy Sensor and my 25 watt 30 ohm resistor is mounted also so it can be attached during a wind tunnel test.

So if the technology that runs your cars power windows can be adopted to the way wind turbines YAW to face the wind. And a KidWind team can work to design, build and solve all the problems that  present themselves during the process. I say KidWind is a great hands on learning that covers all the S.T.E.M. bases and more!

Thursday, May 9, 2019

To YAW or Not To YAW? That is the question.

Added to the 2019 National KidWind Challenge this year is a YAW component challenge. Turbines will be placed in the wind tunnel on a turntable. After the blades get up to speed the turntable will be rotated 90 degrees. This will simulate a "real world" change in wind direction experienced by all real wind turbines. To adjust to this "change" in wind direction the turbine will need to YAW (rotate) to keep the blades facing into the direction that the wind is coming from to keep them rotating and maintain energy output.

Sounds easy, right? Lets see...

There  are basically 3 different ways wind turbine are constructed to accomplish YAW. Two are passive (relatively simple) and one is active (very complex). There are pros and cons to each method and that gives KidWind teams something to think about and consider.

The first passive system is one that most people have seen and is the type used on old farm water pumping wind mills. They operate with a tail that is behind the tower and blades. The blades operate UP Wind of the tower and Nacelle. The tail acts like a weather vane and keeps the blades facing  directly into the wind if it is the correct size and shape.

The problem is to engineer the attachment of this tail so that it can rotate the Nacelle that holds the blades, gears and generator. Good problems to solve and many options to choose from.

The second passive system is the Off Set Pivot. The blades operate DOWN Wind of the tower and Nacelle. In this system the wind force on the blades causes the Off Set to Pivot and rotate so the blades are facing against the wind direction (down wind of the tower). Some wind force is blocked due to the tower and Nacelle getting in the way. This is referred to as tower shadow. No tail or system to mount the tail is needed. However some weight balancing needs to be done to reduce the load of the blades and Nacelle that will be placed on the Pivot bearing.

Lastly in this discussion is the Active - Motor Driven system. All utility grade wind turbines use a system like this. It is very complex, expensive and good at providing YAW for maximum energy output. This requires two sub-systems. One that can determine the direction the wind is coming from.  And another sub-system that can rotate the Nacelle and Blades (this is a VERY BIG job) and automatic communications between the two systems.

In my model, as a proof of concept I used the existing technology the runs your electric windows in your vehicle. At the bottom of the picture you have a wind vane between two micro switches. This determines which way the wind is coming from. If the wind is coming straight on the vane is in the middle and no switch is on. In the top part of the picture you have a large gear that can be rotated CW or CCW by the small gears driven by the three small DC motors when they receive a signal ( polarity + or - ) ( polarity - or + ) from the micro switches if pushed to the left of right (up or down in this picture) by the wind.

I will let the circuit drawing do the talking here on how it is wired to reverse the polarity and thus reverse the direction the motors turning the large yellow gear CW or CCW.

In my model I applied the Proof of Concept by fixing a ring gear to the stationary part of the tower mounted to the tower base. The green gear is glued to the white PVC and then set screwed to the 1" black pipe.

The wind direct "signal devise" (wind vane with two micro switches) is mounted to the top of the Nacelle behind the blades.

The circuitry, relays, battery and drive motors are mounted to a plate that is locked to the main
1 - 1/4" PVC pipe that slides over the 1" Black Pipe than the green gear is set screwed to so it cannot rotate. The 1 - 1/4" PVC rides on a thrust bearing and allows it to rotate. The small green gear on the left in the picture turns when it get a signal from the micro switch. Since the large green gear is fixed (set screwed) the motor and plate it is attached to rotates the 1 - 1/4" PVC, Nacelle and blades to keep the blades pointed facing the wind. YAW!

Everything you see here from the wooden plat up rotates around the green gear that is set screwed to the the 1" pipe screwed into the base.

Active YAW system model. It will be interesting to see what the different KidWind Teams come up with to solve this years YAW Challenge problem.  Plenty of good stuff to learn and apply. YAW'al!

Saturday, April 27, 2019

Safety, Tower Climbing and KidWind

What do Safety, Tower Climbing and KidWind all have in common? Well if you are on a KidWind Team at Darlington Middle School you learn a lot about the design, building and testing of model wind turbines to produce electricity. Then if the you are lucky you get to see and learn about climbing wind turbine towers, the equipment used and the attention to safety that everyone in the industry must consider and maintain. SAFETY is number one!

I learned about ENSA (ensa-northamerica.com a Division of Mallory Safety and Supply) located in Mukwonago, WI at last years National Kid Wind Challenge in Chicago. There I met, director of operations,  Valerie Marquis and we talked about the KidWind program and what the kids were learning. Since safety in the wind power industry is their business I thought this would be a great opportunity to expand the learning for the KidWind Teams so we set up a demonstration/presentation in Darlington on my wind turbine tower next to the school.

I cannot say enough about the ENSA people and the work they did with the Darlington Middle School KidWind teams this past Friday, April 26, 2019 but I am going to try.

The weather was great! April Vollm and Rob Siegel from ENSA arrived early to look the tower over and rig the lines that they would use for the climbing demonstration and rescue of an injured climber from the tower. Students were told that this type of training is required by OSHA every two years, from people like April and Rob, for wind turbine climbers to be certified to work.

April met in Roger Zee's tech ed room (Roger is one of the three KidWind Team coaches in Darlington) with the KidWind Teams and some of Roger's students. The KidWind teams showed April the wind turbines they built to win the 2019 Wisconsin KidWind Challenge in Madison and have been improving (adding a yaw system) to compete in the National KidWind Challenge on May 21-23, 2019 in Huston, TX. April explained some of the work she does and how important SAFETY is to everyone. Especially in the wind energy industry.

From the classroom it was over to the workshop at my home and some "show and tell" about the equipment, how it works and how it is used. April is a natural at this, keeping the students engaged and encouraging them to ask questions and learn more about what they were hearing and seeing.

One of the main pieces of equipment April showed the students was the 50:1 ratio winch that she would be using to rescue Rob (playing the injured climber) in the demonstration. The girls could easily relate to the ratio as the wind turbines they built have a 1:32 ration gear train to drive their generators.

I cannot help but to imagine that some of the girls knowing the make-up of the gears for their 1:32 ratio and how they are assembled thinking how the 50:1 ratio and what type of gears are used in this piece of equipment. The design? The engineering? The application of something they learned in KidWind. Priceless!

It was time to get out and see all this equipment and training put to work, up close and personal. Rob and his helper had rigged the lines on the tower. After a "Buddy Check" (climbers always work in pairs) Rob climbed up the tower and prepared himself to be rescued. April continued to engage the students using the same terminology she does with actual turbine technicians training in the field (Buddy Check, PFP, Self Evacuation Kit, Limited Fall Arrest, Anchor Points, Helmet Ratings E and C, Connecting Devices and Cows Tail just to mention a few).

Now for more good stuff. The climb. April in the green helmet has climbed up the tower after assessing the situation, calling the rescue people and determined the course of action needed. She has placed herself above Rob and determined that he needs to be lowered safely down from where he is to the ground and waiting emergency personnel. Rob easily out weighs April by 100 pounds. She attaches the winch to the tower above Rob and make the necessary attachments.

After making the connections Rob is being lowered down safely to the ground for a successful rescue and treatment by EMT's. If this was an actual rescue in a wind turbine tower all the equipment and rigging would be left "as is" in the tower for the accident investigation crew. This is done for several reasons but one of the main reasons is to learn from the accident and make any necessary corrections to equipment or procedures to prevent it from ever happening again in the future. SAFETY really is number one in the wind energy industry.

And THANKS to ENSA and people like Rob and April these Darlington Middle School  KidWind Team members get it! They know, just like the people that run and service the Quilt Block wind farm that EDP Renewables operates in Darlington, WI.    SAFETY IS NUMBER ONE!

Join a KidWind Team and have some "serious fun" today!
Dick Anderson.  KidWind Advisor.  Darlington, WI  53530

Thursday, April 25, 2019

KidWind Packaging Challenge

In preparing for the 2019 National KidWind Challenge in Huston, TX this May 21-23 I have the opportunity to work on my packaging skills to ship items to the competition.

Although the KidWind Challenge is about producing electricity with the turbine you build you have to have some wind to make them work. This year they will be adding the two wind tunnels that I built for the Wisconsin State KW Challenge. The tunnels are folded down for storage and the two barn fans placed outside on the 4' by 5' pallet I built.

Now getting them to Dallas is only half of the job. The shipping container must be reassembled to protect the wind tunnels and fans for shipment back to Wisconsin. For this I color coded all the pieces  so they can be put back together using the same screw holes.

I will crate it up at my house. Then the feed mill guys will pick it up with their fork life and take it to their loading dock for pick up by the carrier for the trip to Huston.

Now the next packing job was to show the KidWind teams I work with how they could pack their turbines for checked luggage on the plane for the competition.

The first step is to find a nice crush proof suitcase. My old Sampsonite I used for several Odyssey of the Mind coaches competitions did the trick.

The inside looks like this. The green thing is a 15 pound truck brake drum that is used for the base of the wind turbine. In the center is the nacelle and the surrounding boxes hold the blades, extra parts, tools and bolts need for assembly. The tail is below everything and the tower is in the back. The piece of 1/2" OSB in the lid acts as the top half of the "sandwich".

The key to it is that the brake drum is bolted to another piece of 1/2" OSB and the OSB is fitted to the suitcase. So everything is held solidly in place. The tail is placed below this OSB piece and well protected. When the case is closed everything is "sandwiched" tightly together. No movement allowed. We are prepared for the most careless baggage handler the airlines can find!

And here you have it. All assembled and ready for the wind tunnel. The only bad thing is that the suitcase is from my college days was made in 1969 before they thought of putting wheels on them.

Packing Challenges met!

Sunday, January 27, 2019

Power system for Hot Wire foam cutter

What KidWind Challenge team would not want to be able to design and make aerofoil shaped blades for their competition turbine? Imagine being able to do it with minimal effort and cost. Imagine being able to repeat the process and make a set of blades in just a few hours! The blade in the picture shows an aerofoil blade with a twist made using this system. Read on and you too will be able to do this from low cost styrofoam insulation material and lamination film used in most schools. The design possibilities for your KW team are are endless.

Let me back up a bit and fill you in on the full story...

The idea started out simple, as most do. I would use my Schumacher 12 volt battery charger (remember that name) as a power source to heat up a piece of stovepipe wire. This wire would be curved to form the cross section shape of the aerofoil I wanted. It would be mounted in a board with the aerofoil shape sticking out. Then pieces of precut styrofoam would be fed through it. The extruded shape coming out the other side would be that aerofoil shape. Wallah! A groove for the blade mounting stick cut in similar fashion and glued in. Then the whole blade was covered with the plastic lamination film using a hot iron. Worked like a charm.

OK. So how could the process be modified to improve it by being able to make blades with a twist? The wheels started turning. To see this process you will have to go back to my 4/15/18 post titled "Making Air Foil Blades with a Twist". Lets just say sometimes your first idea may not be the best idea.

Moving on. I thought more about the hot wire and how I was using it. A good friend of mine that makes his own blades for hovercraft that he builds was consulted. He gave me all the help and information I needed to improve my early hot wire design. And he was using his Schumacher 12 volt battery charger. I was on fire! This was a great idea and I wanted to share it with any and all KW teams so they could use it also.

Working with teachers and knowing first hand the time and effort needed just to put together a KW team for a challenge was a lot. To help any team interested in using this hot wire process I made up 10 "kits" that included the Hotwire frame, grooving tool and foam holder that would be needed. What they would have to supply was the styrofoam and Schumacher 12 volt battery charger. A pretty common thing to find to borrow or they sell them at Farm and Fleet for about $75.

I took the system on the road to a couple of classroom visits to promote KidWind. The kids took right to it. They were making aerofoil shaped blades like hot cakes!

Here you can see the two girls are following the wooden cross section guides that are hot glued to the ends of the styrofoam blank being held in the clamping setup. You cannot see the Schumacher battery charger, just the two alligator battery clamps between the operators hands. Now that they had the hot wire and understood how to use it ALL they needed to do was get a Schumacher Model SE 1052       2 amp 10 amp 50 amp MANUAL battery charger and they would be in business. My work was done?

I though that I would have the Darlington team buy one of these Schumacher chargers and then bring my old model SE 1052 home. A funny thing happened on the way to a successful purchase. They have discontinued making the MANUAL SE 1052! The NEW models are AUTOMATIC with built in electronics that turn the charger down as the battery they are being used on charges up and will not heat up the wire in the foam cutter. What to do?

Got on line and found Jacobs Online at sales@jacobs-online.biz  to get the transformers I needed to match the stainless wire I had built the "Kits" with. These guys are great. They helped me get all the things I needed to stand-in for the Schumacher battery charger. Plus they were better matched to the resistance of the specific stainless steel wire I used and work better!

Here is what the parts look like. You will need to build one of these, as shown for the groove cutter and another using a different transformer for the main aerofoil shape cutter.

Here is top view of the power supply. I drew in the physical wiring connections so the KW teams can study this and maybe learn more about electricity. I will be working on a schematic for building this for another Blog Post in the future. Note: If you build one for MY "Kit" frame it will work. IF you make your own frame using nichrome wire you will need to do more work with Jacobs Online and pick a transformer that matches the specific resistance of the wire use. This will take more time but be a good learning experience!

If you or someone you know wants the details for building one of these just let me know and I will be happy to help out. The cost of materials for building one of these is around $75-$85. But they work and make the process possible.