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| PHY589 - Myers |
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Physics 589 - Summer II - Myers
Create a new web page for the reports for Summer II 2008. This time there will be weekly rather than daily reports. Email Dr. B your new URL when it is ready. July 7, 2008 - Jul 10, 2008 Post all of your theory solutions to this section of your new online report. 1. z-motion only 2. rotation 3. rotation + z-motion 4. x-motion only Include a link to your Excel Coil Design worksheet that we began here: /ManageSpace/uploads/CoilDesign.xls July 14, 2008 - Jul 17, 2008 Begin writing your thesis proposal. * Proposal Preparation http://www2.sfasu.edu/graduate/CurrentStudents/thesisguide_2.html * Wager's Example: http://observe.phy.sfasu.edu/Misc/wagers/thesis/proposal/....%20ajw.doc * Johnson's Example: http://observe.phy.sfasu.edu/Misc/johnson/public_html/proposal/....%20Preliminary%20mlj1.doc * Scurlock Example: http://observe.phy.sfasu.edu/Misc/stewart/proposal/ss_thesis%20proposal_final%20draft.doc * Blank Form: http://observe.phy.sfasu.edu/Misc/peterson/thesis%20proposal%20form%20blank.doc Consider using quotes from Shawn Frayne in your proposal from his 2 message below. [Work on 2 to 5 physics problems per day in preparation for the qualifying exam. Show solutions to Dr. B.] July 21, 2008 - Jul 24, 2008 Assignment: Modify this code to have 2 loops (nested) that calculates the number of turns ... and then the EMF. July 28, 2008 - Jul 31, 2008 Work on the thesis proposal. Work on 2 to 5 physics problems per day in preparation for the qualifying exam.
Include a link to the wind belt data: /ManageSpace/uploads/BeltData.xls
Aug 4, 2008 - Aug 7, 2008 Work on the thesis proposal. Work on 2 to 5 physics problems per day in preparation for the qualifying exam.
Eric's Summer II Site http://myersem77.googlepages.com/physics589summerii Notes:
Out of Date Plan:
Shawn Frayne Email - July 4, 2008
Great to hear from you and to hear about your course.! I'll be relaunching the website, www.humdingerwind.com, in mid-September with some answers to some questions that you and your students may have. But, in the meantime, as for the placement of the magnets: the choice has to do with trying to achieve a high-frequency of belt oscillation, and a stable mode of vibration. I will say that the configuration
depicted in the PopMech videos is now somewhat outdated, given some new approaches that my colleagues and I are taking (although it is still a good experiment, I believe). I hope to explain more fully in a future FAQ section of the new site.
And as for the 'black box', that is an inexpensive low-power power conditioning unit that can be used (and in most situations will be) in conjunction with a supercap. or battery.
Thanks again for the interest, and I hope that the new materials I'll be posting will help with future courseware....
-Shawn
======================================== Shawn Frayne
Humdinger Wind Energy, LLC
Honolulu, Hawai'i
Hong Kong SAR
(coming soon: Cap-Haïtien, Haiti and Xela, Guatemala)
===================================================
Found at Instructables Forum
I'm the windbelt guy, Shawn, and I have to say, I'm sort of honored that this thread has started on Instructables. I don't want to contaminate your re-creation efforts with the specifics of what I did for those prototypes in the PM video, but I did want to point out a few hints:
-The Windbelt, even the crude protos in the videos, can take airflow from a variety of attack angles and still pump out juice. Something like 60 degrees of variability works out surprisingly well (of course, power drops with the reduction in exposed cross-section of the vibrating belt). Also, unlike with most turbines, the Windbelt can take airflows that are either turbulent (e.g., from a ventilation fan, or around buildings) or laminar. -While on the topic of turbines, a nuance that I'm getting some heat for: In the PopMech article, I say that the Windbelt technology is 10X more efficient than micro-turbines. Micro! Not big turbines. You can crunch the numbers -- the most well-known micro-turbine work was published in Nature a few years ago...just do a search for 'wind-powered WiFi' and you'll find it. Also, you can find the refs on the "Windbelt" section of the Humdinger Wind website. So, that's the benchmark that we'd compared ourselves to there, just for clarification... -The windbelt embodiment in those videos can take airflows of between 4-14 mph without any adjustment, and the power output increases accordingly (not quite to the cube of the windspeed, but close). Above 14 mph, the reported-on protos sort of hiccup, and maintain a constant power output. Which is totally not good enough for a real, rural lighting app. So, I am working on expanding this "bandwidth" to about 4-24mph for larger belts, without resorting to a dynamic tensioning system (which of course is festering in my mind too, for really large installations) -You can use a whole lot of different materials for the belt and get some output, but it's easy to get a few orders of magnitude less output than you can with better materials -- I've used Mylar-coated tafetta, after trying a few dozen other materials, and that works pretty well -- super thin polyester tape (used to repair film reels) works OK, but is loud (but is available from McMaster, so a plus) -- also, the dimensioning of the belt and its balancing is key. Super key. But I'll be curious to hear about what you all discover... -The protos shown in the video run at around 90-100hz in 10mph wind. The AC output before conditioning is pretty much a perfect sine wave, as you might expect. -You have to balance your system so that the magnets oscillate up-and-down, without much torsion. The magnets should feel like they will break your fingernail when they're moving (um, slight exaggeration, but when you get it, you'll know what I mean). This is a much, much more substantial mode than a simple torsional mode. This is the wizard behind the curtain. -That coil setup shown is not the most efficient, at all. But it works at low windspeeds. Other configurations are much more efficient at higher speeds. -After experimenting with several generations of the small, 45.5 cm long windbelts, I've figured out how to reliably make them run quietly. Really quiet, like a leaf in the breeze quiet. So it's possible on those scale for sure....on the larger scales, well, let's say that's a work in progress. I'm super excited to see if some folks in the Instructables community can recreate my results (or better) without any more clues than that. I'm treating this like an experiment for how ideas spread, but if that annoys you, of course shoot me an email and I will give you more details if I can. I will say that I am preparing a formal tech brief/Instructable, for a slightly larger Windbelt -- I'm working to make it failure-proof in random reproduction, which the current design certainly is not, so I'm telling folks I'll have it posted on my website and/or here by mid-January. Thanks again for the interest, really -- and like I said, feel free to email me with questions -- I am under a flood of emails now, but I'll get to them all. Email's on my site. -Shawn |