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Tesla patent 512340
Posted by Jerry Anderson on 2/21/2006, 9:26 am Thanks very much, Jerry
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Re: Tesla patent 512340
Posted by Bert Hickman on 2/23/2006, 2:22 pm, in reply to "Tesla patent 512340" My responses are interspersed below... --Previous Message-- Thanks for the kind words! : I'm currently Tesla was actually looking for a winding method that would reduce the effects of "self capacitance" between turns within a winding. This was an important factor when dealing with high frequency circuits. Using a single layer spiral (as in the patent you mentioned) is only one technique that can be used - there are others as well. However, in your application, winding self-capacitance is really not a problem, so you are free to use any winding technique that is easiest for you. The magnetic field will increase with increasing turns or increasing current. : I am pulsing the coil with about 300vdc through a commutator but The field will consist of loops that pass through the center region of the coil, then loop around the coil and back through again. The actual shape will be a function of the shape of the coil winding and the size of the open center space. For a solenoid shaped coil, the field looks very similar to that of a permanent magnet. For example: : 2). Will stacking the coils (and connected in series) increase the It depends on the current flowing through the single and series connected coils. If you force the same amount of current through the series connected coils, then the magnetic field will double. However, if the current flow is limited ony by the resistance of the coils, then connecting the coils in series will result in only half the current flow. In this case, the ampere-turns is the same as before, so the overall magnetic field will also be the same as before. : 3). When permanent magnets are stacked, at what point (er how many) will It really depends on how the magnets are stacked and which way they are magnetized. If you stack them in "series" (N-S-N-S), then a pair of magnets can be significantly stronger than one of the magnets, but NOT 2X as much. Eventually, stacking no longer increases the field strength - how quickly this occurs is a function of the magnet pole area versus its thickness. For typical magnets, the point of minimal increase may be reached with a stack of only 3-4 magnets. Generally, a single larger magnet will outperform a similar sized stack of smaller magnets. : 4). What is the best way to switch 300vdc @ about 50ma? A power transistor, such as a MOSFET, IGBT, or a bipolar junction transistor can be used. All of the above transistor styles are available in voltage ratings that will easily do this job. The type of transistor you select is mainly a function of how you intend to turn the transistor on and off. MOSFET’s and IGBT’s are turned on by applying a voltage to the Gate lead of the device. A bipolar transistor requires applying current into the Base lead. Irrespective of which device type you choose, you also need to provide a protection circuit to handle the voltage that’s developed across the coil when you attempt to turn off the current. A diode, or a combination of a diode and resistor, connected "backwards" across the coil, will do the job. Trying to switch off the current flowing through a coil without the protection circuit will cause a high voltage transient that may damage, or even destroy, the transistor. No. The polarity of the field does not change unless you actually reverse the current that flows through the coil. If all you are doing is turning DC power on and off to the coil, the field will increase and decrease, but will not reverse polarity. If you also have a moving magnet nearby you may induce current into the coil. The field created within the coil will always be in a direction that opposes that of the moving magnet. Good luck and best regards, Bert
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Re: Tesla patent 512340
Posted by Jerry Anderson on 2/24/2006, 1:49 am, in reply to "Re: Tesla patent 512340" You mentioned that to increase the magnetic field one could add series coils so long as the current remained constant. How does voltage affect the coil? I've been trying to understand this patent better but am having difficulty. Tesla mentions that if the coil is wound with parallel windings where the output of one is fed to the input of the other then "the potential difference between any two adjacent points in A and B will be 50volts and as the capacity effect is proportionate to the square of this difference, the energy stored in the coil as a whole will be two hundred and fifty thousand as great". What is he actually saying here? To me it seems as though something happens to the energy travelling through the coil when the windings are in parallel that magnifies the same effect in a regular wound flat coil. I guess what I'm asking here is whether or not winding the coil in parallel will give me a greater magnetic field with the same input as opposed to a regular single wound coil? So when power is stopped to the flat coil the magnetic field doesn't collapse but is only reduced? Would it be better to ground the input or reverse the polarity of the input? Your knowledge base is quite extensive and impressive and I certainly appreciate you taking the time to share what you have. If you don't mind my asking what is your background and your claim to fame so to speak? Oh, before I forget how can I reduce the voltage of a 12volt system down to about 2 volts or less and maintain a decent current level? Have you ever done any testing with H2 generation by electrolysis? What are your thoughts? Thanks again.
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Re: Tesla patent 512340
Posted by Bert Hickman on 2/24/2006, 12:05 pm, in reply to "Re: Tesla patent 512340" When powered from a DC voltage source, the current through the coil will max out at I = V/R where V is the applied voltage and R is the combined resistance in the coil(s). For a given configuration of air core coils, doubling the voltage will double the current, and double the resulting magnetic field. Either approach can work, but you'll encounter other "engineering" problems (switching transistor voltage capability, coil winding insulation strength) when running much above 1,000 volts. You can also run a number of identical coils in parallel to achieve similar results at lower voltage (but higher current). High current, moderate voltage transistors are inexpensive. High current, high voltage transistors can become very expensive, particularly above 1700 volts. : Tesla was trying to minimize the effects of winding capacitance since this application was intended for radio frequencies. Individual turns within a coil winding form small capacitors to other turns since they are in close proximity to nearby turns and there is a voltage differential between the turns. In a capacitor, the energy stored in the electric field is proportional to the capacitance times the voltage differential squared. In the case of a coil, the voltage Tesla mentions is really from a given winding turn to nearby turns. In a multilayer coil, the voltage difference (between a given turn in one winding layer to the turns in winding layers above and below) will be considerably higher than the voltage difference between adjacent turns in a flat spiral. Since the energy stored in these little capacitor goes up as the square of the voltage, the energy impact of the winding capacitance will be much greater in a multilayer coil thatn for a simple Archimedes spiral coil. However, the bottom line is this particular patent has absolutely NO bearing on what you are trying to do in your motor design since you will be using relatively slow, switched DC coils, and not high frequency AC. At low frequencies or with DC, inter-turn capacitance effects are negligible and can be ignored. : To me it seems as though something happens to the energy travelling No. For your application, you are more likely interested in maximizing the number of ampere turns within a given winding volume in order to get the maximum magnetic field. A simple multilayer coil is probably better suited for your application than using stacks of single layer pancake windings, and multilayer coils are considerably easier to fabricate. : So when power is stopped to the flat coil the magnetic field doesn't When you remove power, the magnetic field collapses at the same rate that the current falls to zero. When the winding current reaches zero amperes, the magnetic field is also zero. The magnetic field will not reverse unless the direction of the current flowing through the coil also reverses. If you are driving the coil from a DC source through a simple transistor switch, the field will rise to a maximum of Vin/Rcoil, and then fall back to zero when the transistor turns off with no current reversal. The actual rate that the current falls to zero in your application will be a function of the specific protection circuit that's used across the coil (to prevent overvolting the transistor) and the inducance and resistance of the coil(s). Thanks for the kind words. I'm a retired electrical engineer and high voltage hobbyist. See: No claims to fame, however... :^) : It really depends on the desired efficiency and the nature of your load. You can use a dropping resistor (simple, but no regulation and very inefficient), a series pass transistor/voltage regulator, or (for greatest efficiency) a DC-DC converter. Unfortunately, the operation of switching regulators and converters can become quite technical. You can find much more information by Googling on terms such as "series pass regulator", "switching regulator", and "DC-DC converter". Here are some examples: : Good luck and best wishes, Bert
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winding directions
Posted by MrHed on 5/18/2007, 1:12 pm, in reply to "Re: Tesla patent 512340"
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Re: winding directions
Posted by Bert Hickman on 5/18/2007, 7:21 pm, in reply to "winding directions" The winding direction does not matter for a Tesla coil that has a single primary and secondary winding. If you post some pictures or provide more details about your coil, we may be able to help you improve its performance. Poor performance often means you may have a problem with tuning, Other causes can include a poorly designed spark gap, poorly performing tank capacitor, low HV power, or improper design or construction techniques. I'm not familiar with the Prague System - Tesla did all of his high frequency work after he had immigrated to the US. Can you provide any additional information about it? Best regards, Bert
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Re: Tesla patent 512340
Posted by Jerry Anderson on 2/27/2006, 10:15 am, in reply to "Re: Tesla patent 512340" --Previous Message-- Again thank you Bert. : You mentioned that a mulitlayer coil would be better suited and easier to wind than flat pancaked ones. I'm not quite following what the difference would be. The coil that I had planned to use was of course 300 turns of 23awg with a 2" aircore and then pancake 10-15 other layers on top with each connected in series. How is the mulitlayer coil you're talking about built? Lastly as I'm using about a maximum of 300vdc into the coils would it be better to use more turns of a narrower gauge wire or stick with the gauge I have? Jerry
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Re: Tesla patent 512340
Posted by Bert Hickman on 2/28/2006, 12:05 am, in reply to "Re: Tesla patent 512340" Tesla's patent referred to a single layer spiral with NO stacking of layers (since this would actually defeat the purpose of the patent). If you wound a series of single layers and connected them in series, this would create a multilayer coil. : How is the mulitlayer coil you're talking I'd recommend simply winding flat layers, one on top of the other, using tape to separate layers if necessary. Using an applied voltage of 300 VDC, you may also need to have some form of external current limiting (beyond using just wire resistance). You'll also need to look at the amount of physical space you have available for the windings. Because of the relatively low wire resistance of #23 AWG wire, you may need a way to externally limit the current that will flow through the coil, or limit the ON time versus OFF time (duty cycle) so that the winding doesn't overheat. Looking at 23 AWG: Close-winding 23 AWG magnet wire will only give you about 41 turns/inch, so no matter how you wind it, a 4500 turn coil will occupy considerable space and weight (probably at least 7-8 pounds of magnet wire). 23 AWG has ~20.3 ohms/1000 feet, and about 648 feet/pound, so you'll need to bend the numbers for your proposed coils. I'd suggest using a significantly smaller wire diameter (perhaps #28 or so) so that you can get higher winding density, particularly if used with a high duty cycle. Assuming 8 pounds of wire (almost one 1 mile of wire), the resistance would be about 105 ohms. For 300 volts, the steady state current would be 2.85 amps, and the power dissipated in the coil (as heat) would be about 855 watts. With no external current limiting, the coil will get VERY hot, VERY quickly, and will burn up. : Jerry Bert
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Re: Tesla patent 512340
Posted by Jerry Anderson on 3/27/2006, 3:10 pm, in reply to "Re: Tesla patent 512340" --Previous Message-- If you have time can you take a peek at the guy who posted his notes and schematics on his water powered 1978 V8 Camaro. It's at http://www.waterpoweredcar.com/1978camero.html and let me know what you think of his circuit. His piggy backing of a half wave rectified signal on top of the distributor output through relay contacts appears to be drawn incorrectly. Thanks very much for your time. Jerry
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Re: Tesla patent 512340
Posted by Bert Hickman on 4/2/2006, 11:25 pm, in reply to "Re: Tesla patent 512340" Yes. The magnetic field is directy proportional to the number of turns times the current flowing through those turns. So, 10 amps thru 10 turns creates the same field at 1 amp through 100 turns. I looked at the site, and my impression is that it seems to be too good to be true... :^) The circuit seems to simply switch the output of the inverter to selected spark plug via relays triggered via a modified distributor. My take on the circuit is that it will not work as shown for a variety of reasons, even if the engine could indeed run on water (which I also am quite skeptical about). There will not be sufficient voltage to fire the plugs, but perhaps some electrolytic action is being proposed to generate O2 and H2. There seems to be nothing magical about the relays - looks like any 2PDT 12 volt relay would do the job. If it seems too good to believe, chances are it is... Bert
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Re: Tesla patent 512340
Posted by Jerry Anderson on 4/5/2006, 2:55 pm, in reply to "Re: Tesla patent 512340"
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Re: Tesla patent 512340
Posted by Bert Hickman on 4/5/2006, 11:44 pm, in reply to "Re: Tesla patent 512340" Hi Jerry, I guess I don't understand just how the water could/would ignite. Whether it's atomized water droplets or water vapor, I simply don't understand what it is that will be ignited. Unless the water becomes somehow disassociated into its constituent elements, there's nothing available to ignite. Perhaps the intent is that the high voltage pulse would do something to the water vapor/droplets (such as creating some hydrogen that could be burned). In any event, please keep us informed of your progress - it sounds quite interesting! Best wishes, Bert
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Re: Tesla patent 512340
Posted by Jerry Anderson on 4/14/2006, 10:20 am, in reply to "Re: Tesla patent 512340" --Previous Message--
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Re: Tesla patent 512340
Posted by Bert Hickman on 4/15/2006, 8:48 pm, in reply to "Re: Tesla patent 512340" Thanks for the additional explanations, Jerry! Using a pair of high energy ignition coils (which I assume the GN packs are) should provide you with some nice high current HV pulses - perhaps even sufficient to disassociate some of the water. Please keep us posted on your progress - it sounds very interesting!
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Re: Tesla patent 512340
Posted by Jerry Anderson on 5/16/2006, 10:52 am, in reply to "Re: Tesla patent 512340" --Previous Message-- Thanks so much for all your great help! We will definitely keep you informed on our progress.
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