Building a Hydroelectric Generator – Honors Project

Good afternoon everyone,

Over the course of the fall 2023 semester, a partner and I took on the task of building a hydroelectric generator from the ground up, with the exception of the motor itself. In this post, I will be documenting and displaying the entire process that we followed, from ideation, through design, construction, and calculation, to the testing of our final assembly. My partner, Mitchell Russotti, will also be making a similar post, so I encourage you to take a look at his post here: Mitchell’s ENGR Portfolio.

Coming Up With A Design:

Alrighty, so let’s go ahead and kick it off with the first part of our process, which was brainstorming different potential designs that we wanted to follow. For this step, we just took out some paper and drew out whatever thoughts came to mind. In the end, we came up with 4 different ideas of how we could design our generator, and we were able to narrow down our options from that point forward.

The option that we decided to go with was the fourth one (right-most); the angular design in which we could place the water wheel between two larger structural components. The main thought behind the creation of the 4th design was that the angled fronts would channel water in between the structures such that the water would spin the wheel, generating electricity.

Creating A Parts List:

Moving forward with our chosen idea, the next step that we took was coming up with a list of different parts we would need to design/acquire to make our idea a reality. The list that we created was as follows:

• Designed:
  • Generator Housing (Frame)
  • Frame Connection Rods
  • Frame Top
  • Gear Wall Mount
  • Gear (Larger)
  • Gear (Smaller)
  • Water Wheel
  • Water Wheel Axle Key
  • Cover Plate
• Acquired:
  • 3 Volt DC Generator
  • Wires
  • Breadboard
  • Breadboard Connectors
  • LEDs
  • Resistors (300Ω)
  • Super Glue

From this list, we then divided up the design process so that we could each work on different components and slowly begin to build up our prototype assembly. The design components that I took on were the generator housing, the frame connector rods, the gear wall, and both of the gears. Mitchell, on the other hand, took on the water wheel, the wheel’s axle keys, and the frame top. For the sake of this post, I will only be detailing how I designed my own components, but if you’re interested in seeing the design of the other components, then make sure to take a look at Mitchell’s portfolio in the link above.

Designing The Components:

Of the parts that I took on to design for this project, the first design that I tackled was that of the generator housing. This piece was really the essential foundation for the rest of the project, and I wanted to get at least a base version of it completed so that Mitchell could get an idea of how long to make his wheel. As such, following the rough design I sketched out in sketch number 4 above, I began by creating the base of the housing, and just extruded it upwards 60 mm. From here, Mitchell added holes on the interior sides for the axle and bearing to sit, and I added rails on one side to slide my gear wall mount in.

       

The only further additions that were made to this design were the connector rod holes on the back end of the housing components, after which I designed the connector rods. For these parts, I simply created a sketch of a circle and extruded it to the necessary length to accommodate the length of the water wheel. This resulted in a circle with a diameter of 6 mm being extruded to a length of 210 mm.

Once these rods were designed, my next big task was to design the gears alongside the complementary gear wall. The first step that I took in this was creating a thin plate of material that would act as the interior wall, for which I created a hole for the main wheel’s axle. This hole, over the course of a couple of modifications, became smaller and began to include a counterbore. The purpose of this counterbore was to hold the gear in place in such a way that when the gear is spinning it will stay steady and not shift back and forth. Once I was satisfied with this central hole, I copied the hole over towards one side of the plate, creating the space for the second gear. The distance between the centers of each hole at this point was 23 mm.

After I had put in the work to create the gear plate and noted the space between the gear holes, I began to work on the gears themselves. The first step in making these gears was to decide upon the size of each gear, i.e. the diameter of each gear. The sizes I decided on were 35 and 15 mm for the large and small gear respectively. With these sizes determined, I started creating the large gear (central gear connected to the wheel axle) by first creating the gear’s central shaft. Extruding this shaft, I created another plane and sketched out the gear using circles to represent the main body. Creating the first tooth for the gear, a length of 2.5 mm, I used a pattern tool to create the other teeth. This resulted in a gear sketch with 15 teeth, which I then extruded creating my final large gear part.

Taking the large gear into consideration, I then created a copy of the larger gear and modified the dimensions so that it would better represent the smaller dimensions. To do this, I went back into the large gear’s geometry and first edited the circular pattern, changing the number of teeth on the gear from 15 to 6. Then, I went into the gear’s main sketch and modified the diameters of the inside/outside of the gear teeth. This rather effectively allowed me to create another gear that was a fraction of the size, without going through the process of creating a whole new gear from scratch. The only issue I ran into during this process was simply decreasing the size of the shaft hole so that it would fit more snuggly on the motor axle.

Thus, with both of the gears (creating a gear ratio of 2.5) as well as the interior wall, the connector rods, and the generator housing designed, I was finally able to start getting things printed out and assembled in Onshape. Below is a list of different pictures that show the different parts that we printed, the different versions of my parts, and a rough assembly with both of our parts combined.

The Final Assembly/Testing:

Once the rough assembly was made, this is the point where Mitchell and I came back together to make any of the modifications that we would need and to start putting together our final assembly. To do this, we acquired a small bottle of super glue, printed off some top pieces (a product of Mitchell’s work) and began to piece things together.

The first thing that we did in this final assembly was glue the axle rods to the wheel axle keys. Once these two axles were dried sufficiently, we then glued the bearings into their respective holes, and glued our axles onto the interior plate of each bearing. In the middle of this process, we also glued the large gear onto it’s respective axle, which had to be done at the same time at the bearing was connected to the axle. This process of gluing these bearings into place, alongside the gear and the axles, though tricky, actually came out rather cleanly, and the bearings were able to spin as they were intended to. Sliding the motor into place, we glued the small gear to it’s axle, and at long last, our internal assembly was effectively completed, outside of drying time. Drilling a hole into the side for the wires, sealing that with hot glue, and gluing the tops onto the frames, our assembly was finally complete, and we were able to begin testing to see if our wheel could produce a reasonable voltage.

Sadly, once we went to place the final assembly into a sink for testing, and turned the water on, we came to realize that the water coming out of a faucet was simply not enough to even turn the wheel. Though we had the wheel on bearings, it still took a reasonable amount of force to spin it with the gears attached, and as such, water from a single faucet was not enough. Thus, without any long wires to use for testing in an actual river, we instead decided to test via manually spinning the wheel. That test can be seen in the video linked below, which shall serve as both a presentation of our project, with a demonstration and a reflection.

Conclusions:

So, as we come to the end of this project, firstly I would like to thank Mitchell for being a reliable partner, and for working alongside myself to get out this project in only a short month and a half (more or less). I would also like to thank each and everyone one of you, the lot of you, I’m sure, for making it all the way to the end of this post. As far as the project is concerned, I do believe I would still call it a success, even if it did not perform in the available circumstances. As it were, it was but a prototype, and at the end of the day, we were able to provide a proof of concept showing that the generator did produce voltage and create a current through the LED.

Regarding the areas in which further consideration would be needed, I do think there are a few problem areas that contributed to the water wheel not working as efficiently as it could have. First off, I believe that the gear system inside is not nearly sturdy enough to provide efficient movement within the current frame. That is both due to the gears themselves as well as to the fact that the frame itself is somewhat flexible (within reason) which could interfere with the gears properly aligning. Additionally, when putting the bearings into the frame and attaching the various axles, we used glue to adhere. It has recently been brought to my attention that in real situations, those bearings would have been attached by being pressed into the material instead, which would allow the bearings to move much more smoothly.

On a completely different note, I also came to realize that we had a conflict in our constraints whilst working on this project. That conflict is in regards to our need to seal the generator inside our frame. In sealing the generator inside, we have thus created a space that, should the generator be providing power for a long period, could potentially get quite warm on the inside. If we were to continue this project in the future, it would be wise for use to consider how to tackle this problem (perhaps by adding some sort of heat sink) as well as the problems mentioned above. Thus, perhaps this project shall and will be brought back at some point in the future; a possible continuation. For now though, a final thanks to everyone involved for a good project, and best of luck in all of our endeavors.

Alex Judson