After a rather fruitless search to find an arc wielder that would be able to supply our power needs, the lab group has taken matters into our own hands. Since our power needs are very unusual, we require 20V at 100A for a 100% duty cycle, only the high-end arc wielders are able to provide us with the right amount of power. Not only are these arc wielders outside of our price range, but the require high voltage, high amperage power circuits which our lab does not have.
So we have decided to, in a way, build our own power supply. Our current plan is to create a network of transformers to power the system.
Today in the lab, Travis, Jon and myself tested to see if transformers in parallel would work the same way as resistors. This means the voltage across the transformers would be equal, in this case they supplied 12.6V, but the current through the transformers would sum up to the total current in the circuit. After running several tests we were able to observe a 5.34A current through a melting 2 ohm resistor. The resistor was only rated to 10W so the longer we ran the circuit, the more the resistor failed. This is a very promising result because it means that we can use multiple transformers in parallel to allow us to reach a high current at around 20V.
The only hesitations I have still is that we did not run the transformers very long, I expect that the transformers should be able to exceed 3A by themselves for short periods of time, so this could be what was happening. Unfortunately any attempt to run the transformers longer than 20-30 seconds or so was prevented because the resistors hit about 210 degrees C according to our infrared thermometer. I also did not think to test the current through each transformer, so we can't be sure if one had more load than the other.
Oh and I thought I would mention Travis had fun lighting up a section of NiCr wire like a toaster by putting 6A through it. We measured temps of around 210 degrees C!!
~Kyle
Sunday, February 22, 2009
Monday, February 9, 2009
Reflections on Outdoor Lab Sessions 2/7 and 2/8
I was very pleased with how the lab sessions went over the weekend. I had been worried about our ability to get the nickle chromium wires to stay down low enough so they would be covered when we put down sealant, but the idea of masonry nails and washers that Kyle and I came up worked even better than expected in my opinion.
I am a bit surprised at how much sealant we went through (2 whole buckets between both coats we laid down), but the important thing is we got everything covered. We added a lot of sand to the sealant, about 35 dixie cups of sand per container of sealant, which is more than I expected we would need, but the sealant just was not getting thick enough with smaller amounts of sand. I am still a bit confused as to why the hydrated lime was so poor in our trials and it may be worth while to contact Ray as to what we may have done wrong. It was just very evident from the field trial from the previous week and the small experiment that Travis and I did in lab that it was causing the cracking on the surface of the sealant as well as the visible white streaks.
I hope we can locate a Power Supply soon as the cold weeks of winter are starting to run out and we really need to test the system now that it is built. Nonetheless, I am very pleased with the progress the team has made this past weekend and look forward to seeing the system in action. I spent a total of 13 hours over three days the past 2 weekends setting up the system and I hope my work was not for nothing and the system will do what it is intended to do, or at the very least give us some good knowledge on how to improve the system.
~Jon
I am a bit surprised at how much sealant we went through (2 whole buckets between both coats we laid down), but the important thing is we got everything covered. We added a lot of sand to the sealant, about 35 dixie cups of sand per container of sealant, which is more than I expected we would need, but the sealant just was not getting thick enough with smaller amounts of sand. I am still a bit confused as to why the hydrated lime was so poor in our trials and it may be worth while to contact Ray as to what we may have done wrong. It was just very evident from the field trial from the previous week and the small experiment that Travis and I did in lab that it was causing the cracking on the surface of the sealant as well as the visible white streaks.
I hope we can locate a Power Supply soon as the cold weeks of winter are starting to run out and we really need to test the system now that it is built. Nonetheless, I am very pleased with the progress the team has made this past weekend and look forward to seeing the system in action. I spent a total of 13 hours over three days the past 2 weekends setting up the system and I hope my work was not for nothing and the system will do what it is intended to do, or at the very least give us some good knowledge on how to improve the system.
~Jon
Sunday, February 8, 2009
Welcome to the Team SnowMelt Blog
Welcome to the Team SnowMelt Official Team Member Blog!
Team SnowMelt is an undergraduate multidisciplinary research team seeking to bring an end to shoveling snow. As part of the Gemstone Program at the University of Maryland, we will gather information, perform lab tests and develop the SnowMelt product over the next four years. At the end of our senior year, SnowMelt will defend our findings at the annual Gemstone Thesis Conference. For more information on research, news, and photos please visit our homepage at http://teams.gemstone.umd.edu/classof2010/snowmelt/index.html
The following posts will include team member experiences as we continue our work on the SnowMelt project
-Kyle
Webmaster
Team SnowMelt is an undergraduate multidisciplinary research team seeking to bring an end to shoveling snow. As part of the Gemstone Program at the University of Maryland, we will gather information, perform lab tests and develop the SnowMelt product over the next four years. At the end of our senior year, SnowMelt will defend our findings at the annual Gemstone Thesis Conference. For more information on research, news, and photos please visit our homepage at http://teams.gemstone.umd.edu/classof2010/snowmelt/index.html
The following posts will include team member experiences as we continue our work on the SnowMelt project
-Kyle
Webmaster
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