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Model Forum / General / Models / July 2009DC motor as tidal turbine model generator
Hello Folks! I am currently working on a tidal turbine model, and need to have enough electricity generated to power a few LED's. I presume to get about 10rpm in the hydraulics lab, and need a few watts to power the LED's. I was wondering, as small DC motors are specified as motors and not generators, how I could find the right one for this application or i anyone had a suggestion for what to use. Many thanks! Jonah Perhaps those that are fitted to wind-up torches. They are cheap enough these days to buy and dismantle. Then you've also a source of high-brightness LEDs > I am currently working on a tidal turbine model, and need to have > enough electricity generated to power a few LED's. > I presume to get about 10rpm in the hydraulics lab, and need a few > watts to power the LED's. I was wondering, as small DC motors are > specified as motors and not generators, how I could find the right one > for this application or i anyone had a suggestion for what to use. > Perhaps those that are fitted to wind-up torches. They are > cheap enough these days to buy and dismantle. Then you've [quoted text clipped - 6 lines] >> specified as motors and not generators, how I could find the right one >> for this application or i anyone had a suggestion for what to use. You are going to struggle to get enough volts with 10 rpm. Some sort of gearing to increase the speed will help a lot but do you have enough mechanical power. Any permanent magnet (model) motor will work as a generator LEDs don't need watts! a few volts and low 10s of mA is plenty per led say 50mW Bob I will try and get my hands on a wind-up torch, but I do fear I will not have enough torque to turn it.. For diameter of turbine, well, it will have to fit the motor I get. I am currently looking at 2 models, one of which is already made but missing. Heres some pictures: http://tidalenergycanada.blogspot.com/ The larger black turbine, modeled after OpenHydro's turbine , is the one I might be able to use if I can find it. It has higher rpms, and has a stable base. The model I am currently working on, the Sketchup model picture, is SMD Hydrovision's TidEL turbine, and is more complex as it "floats" in the current. It will also be quite small, about 1:120 scale (which means the diameter of the pods' will approx. be 2.08cm) Thanks!!! Hello Jonah, Do you really mean 2.08cm?? 20mm? If you do and you are expecting it to turn at just 10PRM then you are in fantasy land if you hope it will drive a generator of the sort you are discussing. As a starting point, just do a quick calculation of the energy in the water that will flow through the turbine. ie 1/2mv^2. That's way more than you will get out for heaps of reasons and I doubt that even if you got it all, you'd be able to light an LED. At 1ms-1 a 1mx20mm column of water contains about 157mJ which is 157mW passing the turbine, if you brought the water to a standstill and converted all the kinetic energy to electrical. Why do you need to 'generate' current for the experiment/demonstration. An external power source and any of a wide variety of sensors to drive/control LED's would indicate the speed or any other parameter you might want to measure. Rdgs Richard >I will try and get my hands on a wind-up torch, but I do fear I will >not have enough torque to turn it.. [quoted text clipped - 11 lines] > >Thanks!!! On Jul 24, 12:48 pm, Richard Shute <sharkface.pi...@toucansurf.com> wrote: > Hello Jonah, > Do you really mean 2.08cm?? 20mm? If you do and you are expecting it [quoted text clipped - 34 lines] > > >Thanks!!! Thank you for the info/ reality check- and yes I mean 20mm for the model to fit in our flume.. but 20mm is the diameter of the pod - the diameter of the blades (2) will be 15cm.. this would give me The project is mainly to observe the environmental effects on the seabed, but one small aspect is to have it power something visual for the high school/investment tours that come around every once in a while. Having the model actually light up an LED would have a greater impact than a spinning piece of metal - Thanks again! > On Jul 24, 12:48 pm, Richard Shute <sharkface.pi...@toucansurf.com> > wrote: [quoted text clipped - 49 lines] > > Thanks again! Sorry posted without finishing.. the 15cm diameter blades would give me 487mW, so 974 mW total. > I will try and get my hands on a wind-up torch, but I do fear I will > not have enough torque to turn it.. [quoted text clipped - 11 lines] > > Thanks!!! I suggest you hold fire on the pictures and put some work into some basic physics. I can't see that working at the proposed scale will yeild the result you are hoping for. Bob >Hello Folks! > [quoted text clipped - 8 lines] > >Jonah I doubt that you'd find anything that would output much at that speed, and a geared-up version would take too much to drive it. What sort of diameter turbine are you looking at using? Peter -- Peter & Rita Forbes Email: diesel@easynet.co.uk http://www.oldengine.org/members/diesel http://www.stationary-engine.co.uk http://www.oldengine.co.uk On Jul 23, 6:06 pm, "Jonah Tremblay - VP Finance, First Year Rep" <jonah.tremb...@gmail.com> wrote: > Hello Folks! > [quoted text clipped - 8 lines] > > Jonah Where do you get the 10 rpm from ....have you been looking at those huge wind turbines ............that's a different scale and a different ball game . Those little computer fans .......if the fluid is funnelled to-wards them..venturi fashion, can be made to turn very fast ..a current of 10 mph can be multiplied ten fold through a venturi..maybe more forget the two bladed props idea then you'll get the power. all the best.markj > On Jul 23, 6:06 pm, "Jonah Tremblay - VP Finance, First Year Rep" > [quoted text clipped - 25 lines] > > all the best.markj The 10 rpms was just the lowest average of the information I could muster on the internet... I have to work with either one of these models, but the venturi system does sound intriguing... As of right now the flume water depth is 34 cm and the speed is 0.24m/s.. Thanks! |
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