Diametric Turbo Generator

[DreamThinkBuild]

Hi All,

This is one of my other projects I've been working on. If you want to make a turbo generator with diametric magnets, find a 6ft light weight carbon fiber yacht wheel, magnetic bearings and a high torque 12vdc motor 400rpm. Mount the diametric magnet so it rides on the rim and place a pickup coil near the magnet. Let that sucker go, with a 72" span rolling on a 3/8" diametric magnet it will be spinning at near 80,672 rpm.

MagnetRPM = MotorRPM*(WheelDiameter/MagnetDiameter) =
400*(72/0.357) = 80672.27 rpm

Attached pictures are of a mock-up I built using Legos. The wheel diameter is only 3.5" the magnet is 3/4 (RC4CDIA from K&J magnetic's), The motor is 12vdc running at 450rpm. The coil is from a small fish pump bubbler looks like 32 gauge wire maybe 3000 turns.

Putting the values in the equation we get:
450*(3.5/0.75) = 2100rpm

So the diametric magnet is spinning at 2100rpm(-frictional losses) and the coil puts out 33.6vdc@8.3milliamps rectified.

With a battery powered dremel at 20Krpm:

20000*(3.5/0.75) = 93,333rpm you start running into major frictional losses and melted Legos.

A 19" bike wheel would be 20000*(19/0.75) = 506,666rpm.

On the bright side at this speed you would only need about 24 turns of wire to get a pretty good voltage.

Here is the chart from my tests using the same 32 gauge coil, magnet and wheel just changing the drive speed, these are open voltage and current no load, rectified dc.

@450rpm from 12v motor = (33.6vdc, 8.3ma)
@10Krpm from dremel low speed  = (29.5vdc, 7.7ma)
@20Krpm from dremel high speed = (61.1vdc, 15.2ma)

The second coil I used was 26guage around 2000 turns.

@450rpm from 12v motor = (7.2vdc 48.3ma)
@10Krpm from dremel low speed = (6.35vdc 48.0ma)
@20Krpm from dremel high speed = (12.8vdc 96.1ma)

You can see the Dremel on low speed drops torque considerably. The current could be increased by using a higher gauge wire and a iron core. This will also induce more drag in the system so a high torque motor is required. Increasing wheel size will also increase rotational speed of magnet and getting larger diametric magnets will increase the current and voltage. A heavy wheel will create a flywheel effect but the initial start up current will be high, so it might be better to engage the load once it reaches full speed.

Something like this would make some power: http://www.kjmagnetics.com/proddetail.asp?prod=RY04Y0DIA if you don't break your fingers trying to install it.

[gyulasun]

Hi,

Nice job, thanks for showing it!

The only thing I do not get in your chart is that you wrote data were open voltage, no load;  still you included current values (8.3mA or 48.3mA from the second coil etc): what kind of currents are these, once you do not have a load across the output DC voltage?

Also, it would be good to check the 12V DC motor's input current consumption, the tests would be more meaningful.

Thanks,  Gyula

[DreamThinkBuild]

Hi Gyulasun,

Sorry for long delay in response to your question. I was reading the power out as solar panels are read as open,no load, direct from bridge rectifier. If I hooked up a 2watt led light to the un-rectified AC portion it would light up brightly and will run a smaller dc hobby motor rectified 9vdc, 45mA unloaded. With the current small design there is no OU. The 12vdc motor is consuming 330mA (almost 4 watts) loaded with the wheel and magnet.

I tried with a 15" bike wheel and a larger gear motor, 12vdc 450mA 200rpm, but the metal bike rim was creating a braking effect with the spinning magnet(Eddy Currents). A large all plastic/rubber wheel is required with more magnets that could be placed around the periphery but spacing must be far enough that the field from one magnet is not interfering with each other. I wouldn't discount the idea though.

I did learn some interesting things from building this project which I will be sharing soon.

Thanks for the interest.

[z.monkey]

Thatz Forkin' Krazy Kewl!
Legos Rox!  Neo-Dia-Mags Too!  LMAO!