More Frame Work

Matt, Jordan and I assembled much of the remainder of the frame on Sunday. It takes quite a while to drill through steel, so we were only able to attach the two long diagonal trusses and the top bearing support. To make a 3/8" hole through 1/8" steel using a hand drill required about 6 different bits - starting with 1/8" and working up to the 3/8" bit.

I was hoping we would be able to create the turbine ribs, but it turns out that welding EMT conduit to black steel pipe is trickier than we thought. Dan from University Theater diagnosed the problem and will hopefully weld the ribs this week. Bob got some work done on the pulley wheels, so I am looking forward to putting them into place.

Also, the flywheel should be arriving soon; it's a 90 pounder salvaged from a John Deere tractor.


Drill-master Jordan.


Me drilling holes for the top bearing.


You can see the two diagonal trusses and the bearing mount up top.

Materials

Jordan and I picked up some 1/2" EMT conduit from the Home Depot and visited Bil at Aerotecture yesterday. Bil sold us 6 lightly used square-flange mounted ball bearings at a very nice discount. We weren't able to use the bender at Aerotecture, but Bil suggested that we try Chicago Metal Rolled Products to coil the conduit for us. Chicago Metal worked on Bil's earlier turbines, before he got his own bender. They also created the curves in the roof on the Ratner Center at the University of Chicago. If you ever need to get some metal rolled, go to the guys at Chicago Metal - they were the most pleasant people to deal with and were kind enough to do the work for free. Ziggy was going to do the coiling, but one of the five Stanleys ended up doing it instead. As you can see from the picture, the coils were perfectly rolled to a 1.5' inner diameter.



Other materials: Last week we picked up a 4' x 8' sheet of 0.093" Lexan from Piedmont Plastics who also gave us a discount. The Lexan will be used to fill the gaps between the ribs.

Nuts and bolts from McMaster should be arriving on Saturday morning, so hopefully we can start putting some things together over the weekend.

Flywheel and Alternator Placement

Bob drew up this CAD layout to figure out where the alternators, pulley wheels and the flywheel will be placed. The alternator in the top right corner will be directly connected to the turbine rotor by a pulley belt looped around the massive wheel Bil Becker supplied us with. The other alternator, at the far left, will be indirectly connected to the turbine rotor, and will rotate with the flywheel. This will be accomplished by using an intermediate shaft (located in between the turbine shaft and the right-side alternator) that will transmit power from the turbine rotor to the flywheel. The lower pulley wheel on this shaft will be mounted on a bicycle freewheel, which will allow the flywheel to continue rotating even after the turbine slows down. In order to compensate for the rotational velocity that is lost by placing a pulley belt between the flywheel and the freewheel-driven pulley wheel, an extra-large pulley wheel will be mounted on the same shaft as the flywheel. This XL pulley wheel will be machined from a solid 24" x 24" x 1" piece of polyethylene, an extremely dense and rigid plastic. This pulley wheel will be connected via pulley belt to the alternator on the left hand side.

Alternator Porn

I took one of the alternators apart to see what it looked like inside. When I opened it up it looked like the magnets might have been rubbing up against the inside of the coils. You can see that the outer edge of the magnets are worn down and the inside of the wire coils are scratched, but this might just have been from the machining of the parts. The shaft seems to rotate a little more freely now, but we might want to file down the edges a bit.


Closed.


Open.


On left: note the rectifier sitting inside the cover. On right: the magnet rotor sitting inside of the coil ring. You can see the three sets of coils that comprise the three-phase configuration.


Magnet rotor.


Coil ring.

3D Turbine Rotor

This is a picture I made using Google Sketchup. I can't figure out how to fill in the spaces between the ribs. These spaces will be closed with either Lexan or Poly-Fiber on the actual turbine.


I will try to make a model of the frame so you can see how the turbine fits inside, and a model of the flywheel and alternator too.

Maroon Article

Read about the New Initiatives Fund and the projects that received funding in this Maroon article.

Turbine Supports

David and I put together the upper and lower supports for the turbine helix today. The lower support is welded to the frame, but the top one will be bolted on. This will allow us, and future custodians of the turbine, to easily remove the helix for repairs or tinkering. I also hammered down the ends of the pipes so we can thru-bolt them to the frame with greater ease. Bob is definitely a superior pipe-flattener.

Two photographers from the Maroon took pictures of me and David for an upcoming article (coming out tomorrow?) on the projects being supported by the New Initiaves Fund.


The frame on its side, showing the lower support.


A good way to take out your aggression.


The upper support.


Getting there...

Over the Weekend

After two trips to the Resource Center on 135th street, we ended up with about 150 pounds of steel for just 10 cents a pound. We're using steel pipe that David suspects was used for farm equipment as our cross-braces, and some really beefy punched steel to build the structures that will support all of the internals (eg the turbine itself, the alternator(s) and the flywheel).

Bob demonstrated with ease, though not without some bruises and burns, how to flatten the steel pipe, which had a 1/4 inch wall (not an easy task for mere mortals like you and me).


Locked and loaded, part deux: beefy steel.