Beginner looking for advice

[Mark Selvek]

Hi folks,

I teach a course called Energy and Power at the high school level. I would like to start them in a Wind Power unit by having them build small scale model wind turbines with materials i have in the shop. Eventually, as a class I would like to attempt to build a little larger turbine that would produce 12 volts of charging power. As for the small turbines, I have some questions.

1. Can I use small DC motors as generators, since i have a surplus of them at school? I believe they are rated at 9 volts and 1.5A @ some insane RPM like 10,000 or more. I fear that they would need to be spun way faster than that to output any readable voltage.

2. If these DC motors won't work for the students, is there an inexpensive way I could go about this. I have 19 students and would like each of them to make their own. My goal is that they could light up an LED or small bulb. I tried chucking the DC motors I have into a cordless drill, and tried reading the voltage with a meter, but got nothing. Either i was measuring it wrong, the meter is bad, or the motor was not spinning fast enough.

Any advice, tips, pictures, plans ietc for a beginner just trying to get going would be awesome!

Thanks

-Mark

[Kricnit Not]

Try http://www.picoturbine.com/ This is designed to educate students on the design of a very simply constructed wind turbine at low cost. Some cheap magnets, some small coils of wire, sticks, cardboard, glue, and a 2 liter bottle is mostly all that is really required. You can make it as easy or difficult as you like.

Kricnit Not

[Joe Blake]

How about this one made from an old venetian blind?

http://www.hydro.com.au/education/discovery/model/wtmodel.htm

Joe

[Kricnit Not]

That is a great site in Australia.

Here is a link to their site with an educational file on wind energy.

http://www.hydro.com.au/handson/students/wind/pdf/wind_power_kit.pdf

As for the hobby motor, it is a very bad choice to generate any usable power, the rpm's required are extremely high.

Try to pull apart a VCR and use the motor for generating power. Here is a link with more information.

http://www.fieldlines.com/story/2005/11/25/204242/17

Or you can use the layout in picoturbine. This layout will work for a VAWT or a HAWT and gives the student a little more practical experience other then just slapping a preconstructed motor in.

Kricnit Not

[Mark Selvek]

Hi folks,

Thanks for all the replies and info so far. I feel like I am getting somewhere. I was wondering if a computer fan motor would work resonably well for generating electricity? If they are, I may be able to obtain a lot of them for free. Also, about the VCR motor wiring, can anyone send me via email or post on here more information on wiring the motor up to the LED's. I have checked out one website on this, but the pictures are a little unclear. I understand that the LED's must be wired opposite of each other to take into account thre AC that is produced. I may be able to find numerous VCR motors for my students to use and make their own models. Basically, I am looking to build something at little or no cost since our budget at school is very limited and it is difficult to purchase things ( a lot of red tape). I would like them to have something they can take home and show off, and have it at least light up some LED's for show. Thanks! selvekm@victorschools.org

Mark

[Mark Selvek]

Hi folks, if anyone is an expert at how to locate and wire up a VCR motor, I am looking for some help. I have the motor taken apart, but can't seem to locate the 3 terminals that are supposed to be there according to info and pix on the web. I will post pix of the motor. The goal here is to light up some LED's like i have seen on the web. thanks for your help

mark

[Rob Beckers]

Hi Mark,

Looks like that board has both the motor and the controller on it. To use the motor as a generator you won't need the controller part. See if you can locate the wires coming off the motor windings. You'll want to tap directly into those.

-RoB-

[Mark Selvek]

Hi Rob,

It is hard to see bewteen the coils and the board, but i can see four soldered connections around the circle where there are green wires from the windings soldered to these points. I was expecting 3 not four since it is supposed to be 3-phase, right? Is the entire PCB not needed at this point? it just seems to be in the way of being able to wire into the start or end strands as i have read about.

mark

[Rob Beckers]

Hi Mark,

Assuming it is indeed a 3-phase motor (I have no clue what they use for VCR motors, if that's the common type than it probably is): If it is wired up in 'star' configuration then all 3 phases connect to a common point, plus the other side of each of the 3 phases makes another 3 connections, for 4 total connections. So, seeing 4 connections could make perfect sense. You'd not need that common point, only the 3 others. Unless you need the PCB for mounting or such I'd say you can get rid of that (or at least scratch through the leads coming from the wires so the electronics won't be shorting out your phases). A little measuring with an Ohm meter should do the trick of finding out what's what in the motor wiring.

-RoB-

[Kricnit Not]

H1, H2, H3

Common not used (will have three wires leading into it).

Also It looks like the board has diodes mounted for H1 -H3 already mounted. You can use these for pulsating DC and just use three LEDs if you like. They may flicker at slow RPMs though(probably wont light at that speed anyway). Or you can remove the diodes and mount two leds for each phase as in the otherpower article. You do want to cut the traces on the board after the point you tie in so as to not have any leakage current to other circuits in the board.

Looks to be a good starting platform as you wont have any eddy current losses due to a steel backing plate. You may want to line up your magnets around to perimeter of the unit. You will probably get the best flux density into the laminates.

http://www.fieldlines.com/story/2006/6/3/164216/2121

Wish you luck

[Mark Selvek]

thanks for your reply, it is starting to come together for me. I still need to play dumb here and get some more pointers on wiring this thing. The three diodes have 2 connections on either side of them. if i was to use three LED's like you mentioned, how do they get connected to the diodes? the problem is, the coil is so close to the board, there isn't much room to work, and i tried on one motor to remove the coil from the board, but that resulted in breaking a few of the coil connections to thier terminals, since they are soldered to the board, I can't just pull the coil off, and i'm afraid i'll forget which terminal they got soldered to. The board doesn't have a back side that i can use to unsolder components since the back is all steel. There is a triangle pointing to one connection on each of the diodes, does this mean anything important? Sorry for so many question, i just want to get it right so I don't ruin this thing.

Mark

[Mark Selvek]

I was successfully able to wire up the 3 phases on the VCR motor to the LED's. I am failing to see why it was necessary for there to be two LED's per phase. All six light up at the same time as far as i can tell. I was able to get them to light up with a spin of my hand, but not when i made some propellers and tried it in front of a fan. it spun pretty fast but apparently not fast enough. I may need to gear it? Thanks to all those who gave me advise and please continue to give me any pointers you may have.

mark