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Old 12-07-2007, 09:03 PM
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Jetijs Jetijs is offline
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Originally Posted by elias View Post
Maybe we can design a system which can stabilize the frequency of the pulses independently from the RPM of the motor. increasing the input voltage, increases the recovered energy a bit.

Are you talking about the motor I am working on? If so, then you have missed, that we already have an independent frequency of the pulses regardless of the RPM's of the motor. The switching is done by a 555 timer.

Ok, I have done some tests today. I used my motor circuit to pulse the coil with a welding rod core. I made these tests with 5 different frequencies. I used two 12v batteries in series (24V) on the input. In the first test I used a 24V battery in the output and pulsed the circuit with one 2n3055 transistor to get the basic results so that I can compare the with other tests. The switching circuit with the 555 timer and the optotrigger consumed 0.09A, that must be taken into account. For the second test I used the MJL21194 transistor soldered on the same base plate parallel to the 2n3055 transistors. This time the switching current was 0.11A, because the PNP transistor now had to switch four transistors instead of three. Basically I got a little bit worse results compared to the 2n3055 transistor, bat I think that this is because now the circuit had to open and close four transistors in parallel thus consuming more current. After all both transistors are working just as good and we can safely say, that the problem is not th the transistors used. In test number 3 I used a light bulb in the output and the 2n3055 for switching. This time I got lower voltages and overall efficiency. And in the last test I attached a 10000uF cap in parallel of the bulb in the output, this increased the efficiency a little bit. Here are the results:




Any comments, suggestions?
It's better to wear off by working than to rust by doing nothing.

Last edited by Jetijs; 01-18-2008 at 01:30 AM.
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