Hi Tommey Reed,

I've been following your work with great interest. I've been working on a small DC turbo generator. Before I begin it is not over unity in any way, just a way to convert DC to AC without using a inverter and the output is a pure sine wave. I'd like to convert it over to AA batteries and solar charge them during the day. A Earth battery would be even better.

My current setup is a high speed DC motor, 5000rpm (reduced when running a load due to Lenz drag), running off a standard 9v battery. Connected directly to the shaft is a diametric cylinder magnet. Three fish pump coils are used for the pickup and are wired in series.

The input 9v 130ma (with magnet load) which is about 1.17watts input.

The output is 208vpp ac which breaks down to
Vp=208vpp/2= 104vp.
Vrms=104vp*0.707= 73.528 (meter shot is pretty close)
Vavg= 66.248

It draws 6.2ma through a 10ohm load = 384uw

The first shot shows the meter connected to it. I used legos for the support structure they allow for fast prototyping, trying different coil configurations and tweaking distances. You can see the three black cords from the fish pump coils.

The second shows a little closer view of the generator. You can make out the diametric magnet in the middle. Can't tell from shot but it's spinning pretty quick.

The third and forth shot shows it running a 1.5watt 115vAC LED accent light from 9v DC. If I pump 12volt in I can get it much brighter and peaking a 361vpp.

If you or anyone else has suggestions on how to make a better low power DC turbo generator I'm all ears.

I like your setup, simple and to the point.
As we all know, energy is what we need to power the homes we live in. Sometime simple is the best way to under energy, most people don't understand what energy is.
Energy is work, just like lifting 10 lb at a height of 10ft is work.
745.7 watts is 1 hp or, 746 watts have to be understand to make energy.
1 hp equals 1 pound taken to a height of 33,000 feet in one minute, is also 1hp.
When we talk about foot pounds, we have to understand it's 12" away from the shaft.
In other words, 24" wheel on a shaft will produce 1 foot pounds on the outer circumference and 12" pounds on the shaft. each revolution of the shaft produce (24" x pi)/12=6.28 ft of work.
33,000/ 6.28= 5254,but we use 5252.
This is how we can calculate hp. (torque x rpm)/5252
This formula is the key to make energy or to power a dc/ac motor.
3600 rpm/60= 60hz on a basic generator, we can find how much torque is needed to produce say 1 hp.
If we take 5252/3600 rpm we get a constant torque of 1.46 foot pounds.
Also we can get the same 1hp with 600rpm at (5252/600)=8.75 ft/lb constant torque.

I know you all know this by now, this is just a reminder of how energy is made.
There is no free lunch in a 746 watts of power....

Tom

I have one dumb question.
What advantages does your system have over using a solid state inverter?
I am not trying to be synical
kind Regards
Mark

Hi Tommey,

My design uses a diametric magnet. The magnet is attached directly to the shaft of the DC motor. I attached a closer shot of the motor and magnet. 3 coils pickup the AC.

I also attached a picture of it's bigger brother. This is using an electric snow blower motor belt driving the alternator (Has high speed and torque). Couldn't find RPM rating on motor(Toro s-210) but says shovels 200lbs a minute of snow. The Kill-o-watt meter shows it drawing 110vac 632watts 6.42amps. Now the Wind Blue is hooked through a bridge for DC output.

http://www.windbluepower.com/Permanent_Magnet_Alternator_Wind_Blue_Low_Wind_p/dc-540.htm

It shows an output of 248vdc @ 15amps = 3.7kw

Hello Marksdansie,

It is a good question, you can spend $800 or more on a pure sine inverter. Also most inverters have a no load/idle power draw(loss) of about 1amp. Running through the coils you get a pure sine wave out with only the cost of the coils ($40). If I fry the inverter I'm out $800+ fry a coil I can pop in a new one for less than $10. DC motors are also quite in-expensive.

The challenge is try to create a small portable turbo generator that can run off batteries or solar directly. Someone suggested I look at RC car motors they go up 35,000 rpm. I was originally using a Dremel tool @ 20,000 rpm but the motor is not built to run very long.

Now the pictures.
Pic's 1 and 2 show the closeup of the motor and magnet. You can also see one of the removed fish pump coil in the first shot.

Pic 3 shows the snow blower motor and wind blue setup. Small wire shelving also makes for fast prototyping and it's portable too.

Pic 4 shows it running showing the snowblower motor drawing 578watts and the wind blue putting out 248vdc.

Hi Tommey,

You are right, the alternator is running unloaded so that is the higher reading. The alternator has no regulator, it puts out three phase AC which is rectified through the external bridge. I'll unhook the bridge and put an AC load on to give you a better reading with a measurable load. Thanks again for your experience, time and interest.

Hi Tommey,

  The final result is it's too in-efficient with this motor setup, the numbers show it clearly.

Results with a 75 watt light bulb run through 2 phase output.
Kill-o-watt measures the input(snow blower motor) loaded 7.67 amp 110vac 720 watt (wow! that is backwards)
Alternator Output measures 146vac 710ma

Results with a 400 watt Quartz Heater. ( 838watts to get a 400 watt heater running)
Input 838 watt 8.53amp 110vac
Output 66vac 1.70 amp

I tried pushing it with a 800 watt heater but the belt started slipping. Too much load and loss with the system.

Think of energy, 746 watts of power. This can be more efficient if you calculate the max rpm's and bring it down to 3800-3600 rpms.
In other words, if your motor is running say 10,000 rpm's you can add more torque when you gear in down to 3800-3600 rpm's.

If your not shore how to calculate gearing take 10,000/3600=2.7 or say 3:1 gear ratio.
This will increase efficiency on your unit...

My dc motor runs at 3800 rpm's, with no load.....

Hope this helps..
Tom