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Here are some things that I have learned. I apologize if this is a rehash of old information. I hope this will help others. I also hope others will contribute additional info, since I am not formally educated in EE.
For the uninitiated, BEMF = back electromotive force, and effects all modern electric motors, as well as generators. The BEMF can be eliminated, however. Examples of No-BEMF motors would be the Bedini SSG, and Dr. Lindemann's Attraction Motor design.
Why do we care? This principle applies not just to motors, but to all electrical inductors, such as transformers and electromagnets. Inductors are used in many OU systems, such as the Meyer WFC, Bob Teal motor, Joseph Flynn PPMT motor, Bedini Energizer, etc etc. Chances are that if you are interested in OU systems, you should understand BEMF.
As I have learned from Dr. Lindemann's Electric Motor Secrets, (which I highly recommend) BEMF is an effect which happens entirely within the wire of a motor or generator, and is created due to the nature of direct electrical induction.
As we all know, moving a magnet past a coil creates a current within the coil. What we aren't taught in school is that there is an additional effect; the BEMF (or CEMF). The Back EMF is created when the magnetic field collapses. This works both ways, whether we are using a magnetic field to create electricity, or using electricity to create a magnetic field. Normally we supply additional power to overcome the BEMF effect, since it exits the coil in the opposite direction from which the current flows while the magnetic field is supported. Below is a simple example of how the Bedini SSG captures BEMF and shunts the power to an alternate power storage device, such as a capacitor or a battery. I owe a thank you to Introvertebrate of youtube for his illustration which helped me understand this. I have recreated his illustration here in a gif file (both are animated, click the thumbnails).
You can test this effect quite easily by creating the simple circuit that I show, but minus the transistor. I like to use the AAA battery packs from radio shack because they have built-in on/off switches, and the leads can easily be pressed directly into my breadboard. Before the test, you short out the capacitor (to discharge it) and measure it's voltage. Then place it into the circuit and switch the batteries on and off quickly. Then pull the capacitor and check the voltage, it should have risen. Now do the same experiment, but replace the inductor with a short. You should see a mA increase in your cap, because any power within the circuit while the battery is connected is then going to be gathered in the cap once the battery power source is gone. Keep in mind that the BEMF is a high voltage, low amperage power spike. You could use a step down transformer to raise the amperage and lower the voltage, if you need. The factor you must consider is this: is your capacitor good enough to store the BEMF pulse? I've been told that the cap's ESR rating should be considered, and that electrolytic capacitors can be quite slow, which leads me to suspect that you may not get full potential efficiency if using an electrolytic. A cap bank of mixed types has been suggested.
For the inductor, I was able to use one of the radioshack magnet wire spools which I had not yet unwrapped. I could tell the wire had been wrapped perfectly, so all I had to do was remove the enamel from both ends (using sand paper) and I was good to go. I later added RG45 rods for the iron core, and super glued them in. I don't recommend RG45, btw, because they will retain magnetism after much use.
I then created this next circuit to shunt the BEMF back to the original power source. In the case of the Bedini SSG, the primary battery.
(no animation)
I'm obviously leaving out any mechanism to trigger the transistor. As John has done in the past, you could trigger it with a Hall effect sensor, or replace it with a reed switch. I have found that using the bifilar coil method is actually the easiest to build though. While it seems to me that the circuit shown above should work for some systems, it does not work for a Bedini system (or at least not mine). Instead, I had to create this variant:
So if we include the sensing coil in the diagram, it looks like this:
(don't forget your neon and 1n4001 on the transistor, I have excluded them here)
I have been able to run my SG rotor-and-coil setup using this circuit and a single battery, so I consider it a success. More testing is needed to conclude if the diodes (which are 1n4007) are fast enough to capture 100% of the possible BEMF power. I consider this a simple no-BEMF motor. I have not yet seen any self-running, OU-type power gains using this circuit. It could be that my coils are simply not good enough. They are exceedingly mediocre. Based on everything I have learned and observed, I would have to say that the OU which John reports would indicate that collecting the BEMF can create more power than was originally induced in the coil, but I personally have yet to see over 100% power recovery.
A simple astable multivibrator could be used to drive the transistor and you would then have a Bedini solid state system. I think this is a little impractical though, since the potential mechanical energy is still there for the taking. Not only that, but it should be possible to use the rotor as a generator, which would load it down, but that also draws less current on the motor, so in theory, it sounds like a good situation over-all.
Additional thoughts and considerations:
If you run a motor with this circuit, then you are constantly taking and replacing small amounts of power from the battery. I have no idea what effect this would have on a battery. It may be desirable to arrange two batteries to be used as a primary bank, so that power is always entering one and exiting another.
Also... use a breadboard, don't use solder! If you blow the transistor, then you're really going to regret having not used one. Not to mention how much easier it is to setup each new experiment...
For the uninitiated, BEMF = back electromotive force, and effects all modern electric motors, as well as generators. The BEMF can be eliminated, however. Examples of No-BEMF motors would be the Bedini SSG, and Dr. Lindemann's Attraction Motor design.
Why do we care? This principle applies not just to motors, but to all electrical inductors, such as transformers and electromagnets. Inductors are used in many OU systems, such as the Meyer WFC, Bob Teal motor, Joseph Flynn PPMT motor, Bedini Energizer, etc etc. Chances are that if you are interested in OU systems, you should understand BEMF.
As I have learned from Dr. Lindemann's Electric Motor Secrets, (which I highly recommend) BEMF is an effect which happens entirely within the wire of a motor or generator, and is created due to the nature of direct electrical induction.
As we all know, moving a magnet past a coil creates a current within the coil. What we aren't taught in school is that there is an additional effect; the BEMF (or CEMF). The Back EMF is created when the magnetic field collapses. This works both ways, whether we are using a magnetic field to create electricity, or using electricity to create a magnetic field. Normally we supply additional power to overcome the BEMF effect, since it exits the coil in the opposite direction from which the current flows while the magnetic field is supported. Below is a simple example of how the Bedini SSG captures BEMF and shunts the power to an alternate power storage device, such as a capacitor or a battery. I owe a thank you to Introvertebrate of youtube for his illustration which helped me understand this. I have recreated his illustration here in a gif file (both are animated, click the thumbnails).
You can test this effect quite easily by creating the simple circuit that I show, but minus the transistor. I like to use the AAA battery packs from radio shack because they have built-in on/off switches, and the leads can easily be pressed directly into my breadboard. Before the test, you short out the capacitor (to discharge it) and measure it's voltage. Then place it into the circuit and switch the batteries on and off quickly. Then pull the capacitor and check the voltage, it should have risen. Now do the same experiment, but replace the inductor with a short. You should see a mA increase in your cap, because any power within the circuit while the battery is connected is then going to be gathered in the cap once the battery power source is gone. Keep in mind that the BEMF is a high voltage, low amperage power spike. You could use a step down transformer to raise the amperage and lower the voltage, if you need. The factor you must consider is this: is your capacitor good enough to store the BEMF pulse? I've been told that the cap's ESR rating should be considered, and that electrolytic capacitors can be quite slow, which leads me to suspect that you may not get full potential efficiency if using an electrolytic. A cap bank of mixed types has been suggested.
For the inductor, I was able to use one of the radioshack magnet wire spools which I had not yet unwrapped. I could tell the wire had been wrapped perfectly, so all I had to do was remove the enamel from both ends (using sand paper) and I was good to go. I later added RG45 rods for the iron core, and super glued them in. I don't recommend RG45, btw, because they will retain magnetism after much use.
I then created this next circuit to shunt the BEMF back to the original power source. In the case of the Bedini SSG, the primary battery.
(no animation)
I'm obviously leaving out any mechanism to trigger the transistor. As John has done in the past, you could trigger it with a Hall effect sensor, or replace it with a reed switch. I have found that using the bifilar coil method is actually the easiest to build though. While it seems to me that the circuit shown above should work for some systems, it does not work for a Bedini system (or at least not mine). Instead, I had to create this variant:
So if we include the sensing coil in the diagram, it looks like this:
(don't forget your neon and 1n4001 on the transistor, I have excluded them here)
I have been able to run my SG rotor-and-coil setup using this circuit and a single battery, so I consider it a success. More testing is needed to conclude if the diodes (which are 1n4007) are fast enough to capture 100% of the possible BEMF power. I consider this a simple no-BEMF motor. I have not yet seen any self-running, OU-type power gains using this circuit. It could be that my coils are simply not good enough. They are exceedingly mediocre. Based on everything I have learned and observed, I would have to say that the OU which John reports would indicate that collecting the BEMF can create more power than was originally induced in the coil, but I personally have yet to see over 100% power recovery.
A simple astable multivibrator could be used to drive the transistor and you would then have a Bedini solid state system. I think this is a little impractical though, since the potential mechanical energy is still there for the taking. Not only that, but it should be possible to use the rotor as a generator, which would load it down, but that also draws less current on the motor, so in theory, it sounds like a good situation over-all.
Additional thoughts and considerations:
If you run a motor with this circuit, then you are constantly taking and replacing small amounts of power from the battery. I have no idea what effect this would have on a battery. It may be desirable to arrange two batteries to be used as a primary bank, so that power is always entering one and exiting another.
Also... use a breadboard, don't use solder! If you blow the transistor, then you're really going to regret having not used one. Not to mention how much easier it is to setup each new experiment...
By the way, I made another animation for youtube:
The trade-offs between using either of these two methods involves the voltage drops in the diodes and the inductive losses of the second coil. That both methods work is now proved by your experiments. The question is, how to set up the front of the circuit to best take advantage of this recovered energy.
question.Anyways I just thought I'd throw my 2 cents in for what its worth.Try not to Flog me to much for this question
.thx
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