Based on Wooden Generator Experiment 1, the circuit was now extended by a bridge rectifier.
For this I used BAT48 Schottky diodes because they consume only 0.2 volts.
A 1000 μF electrolytic capacitor is used as a stabilizing element.
The capacitor buffers the whole a little and the LED should light up longer and more stable.
With a small LED as a consumer, I get a current of approx. 5 mA and a voltage of approx. 1.7 V with fast speeds.
The result is a proud performance of 8.5 milliwatts.
So there is still much room for improvement :-)
The following video gives a brief impression of the rather poor yield.
Why build a generator yourself when everything can be bought somewhere?
The only thing I learn from buying is spending money
I was unable to find a generator that could generate significant voltage and current at low revolutions of approx. 100 * min-1
The generator should be used in a Stirling engine and possibly in a vertically running wind turbine, which does not bring the highest speeds
The generator must also be usable as a motor in order to start a Stirling engine
The generator has to run very lightly in order to keep losses low, i.e. no sliding contacts and no jerking, as with a bicycle dynamo
For use in the Stirling engine, the generator should also represent the flywheel mass, which means that it must have a certain torque
The test generator has to withstand my sons’ attempts to play :-)
The construction must be simple and it must be possible to assemble it without complex special tools
In the following I log a little what I tried to get as close as possible to the goal, which at first glance seems unrealistic. (Neukirchen in April 2009)
Experience report Electricity generation by bicycle and a car alternator
Since I had planned to generate 10 KWh of electricity in 2012 and had reached just 6 KWh as of 31.10.2012, a plan B had to be realized.
Unfortunately the provisional generator for the self-construction vertical axis wind turbine proved to be not helpful.
The required wind strength to get to charging voltage is simply too high.
So if the sun does not shine and the wind does not blow, only muscle strength still helps.
A person can produce between 100 and 200 watts for a relatively long time.
Examples from the Internet
The energy generation by means of muscle strength is nothing unusual, can be read on the pages of Buch der Synergie.
There are professionally built generators for the montage at the bike, but they cost a little.
Then I looked at Youtube and am found there something helpful.
Some time ago I had found a discarded car alternator and dragged them on suspicion times home.
A little bit in the net searched and a nice description to the three-phase alternator found.
I bought a corresponding V-belt at Ebay.
Self-test
On 1.11.2012, a frame was then provisionally made, in which the bicycle can be clamped and the V-belt drives the alternator.
After about 5 hours of tinkering, it was possible to step into the pedals and the alternator spinned.
In order to test whether the alternator works at all, I have a 4.5 volt plug-in power supply (was available) closed to the excitation winding and connected to the output side a 6V 21 Watt bulb.
What was immediately noticeable was, that it was hard to step into the pedals. The 21 watt lamp started to light, burned brighter and burned right through. What a success.
I have as in the video above to see also a switch to turn on the excitation winding attached and the whole test arrangement in the garage next to the 12V battery built up.
When the excitation current was switched on, an extreme resistance was noticeably.
One minute stepping into the pedals and the battery’s charge voltage rose from 12.95V to 13.2V.
But after a minute, my personal performance was at an end.
Ich gehe davon aus, dass ein permanenter (starker) Erregerstrom nicht optimal ist.
Pulse width modulation may be an approach.
I have an ATMega8 microcontroller already in use, to let generated energy consume and to measure how much was consumed.
The ATMega8 microcontroller has 3 PWM outputs, so it can take over this task immediately.
The circuit diagram of the exciter circle is somewhat more complex.
There the current flows with up to 2 amps at max. 14.4 volts. With the ATmega8 with 5V and max. 40mA per output pin this requirement can’t be realized.
On the following circuit diagram for the control and another I oriented myself and finally I purchased at Pollin the SUD45N05-20L.
Tailored to my needs, the schematic should look like this.
