New CDI...
#41
Join Date: Dec 2008
Location: Tracy, California, USA
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My comments in blue:
I attached a photo showing the "new" stator without the epoxy. I customized the ignition coil core and wrapped the coil cores in electrical tape( I don't if it was a good idea, 176F )[I don't know where the 176 degrees F comes from, but my experience with electrical tape is that over time it turns to goo at even 70 degrees F. I would not even consider electrical tape. How about some kind of RTV silicone compound like Dow 3140 or Dow 3145. Its good for like 300 degrees C, and non corrosive curing (unlike bathtub caulk which cures by exhuding acetic acid [vinegar smell]). Epoxy would probably work too. ]. I'm not that familiar with AC, but the coils are connected in series like this :_: this :=: is parallel right? [Series is the best if your going to optimize for one regulator. But two of the stock battery charge windings with two cheap regulators all wired up in parallel may be a simpler R&D endeavor...].Is it OK if I have some magnet wire going out a couple inches from the stator? [This is not a problem electrically. Mechanically the magnet wire is reallt vulnerable to scratches that will short the wire to ground. Noramlly exposed magnet wire is run through protective tubing of some sort such as fiberglass]. I measured the resistance of the ground and the coil and I got ~300 ohms, is that OK because I'm afraid I grounded the stator on accident. [Not good at all. It should be open. Are you sure you're on the right scale? It is hard to picture a short to ground that is 300 ohms when the end to end resistance across the entire coil should be about 0.5 ohms maximum. I'd recheck that again. Make sure you are on the 2K ohm scale (2000 ohms) when you measure that].
The ignition switch is a 5 pole magneto style switch. It has B (battery), G (ground), L (lights,output), S (solenoid), M (kill). When I twist the key to start it shuts off the output but it runs the starter. [I don't know what you mean by the phrase: "shut off the output". The output of what? The coil? The regulator? The stator? The lights?]. I might have to get a different switch or figure a alternative. Can I use my old R/R? I'm not sure if its going to work because I think its half wave. The "old" stator had a charging coil that was 2 coils in one (half coil for lights, half coil for battery) and one smaller coil for ignition of course. So this "new" stator is probably way better! [You will need to but a 4 pin regulator that is full wave GY6 engine style].The old coil had string wrapped with the magnet wire, and was kept into place with fabric and some kind of sealant. [Which coil? Was this the ignition power coil? Winding a coil with a combo of wire and string is a classic method to reduce disributed capacitance].
All this is relevant to New CDI.... Right?
The ignition switch is a 5 pole magneto style switch. It has B (battery), G (ground), L (lights,output), S (solenoid), M (kill). When I twist the key to start it shuts off the output but it runs the starter. [I don't know what you mean by the phrase: "shut off the output". The output of what? The coil? The regulator? The stator? The lights?]. I might have to get a different switch or figure a alternative. Can I use my old R/R? I'm not sure if its going to work because I think its half wave. The "old" stator had a charging coil that was 2 coils in one (half coil for lights, half coil for battery) and one smaller coil for ignition of course. So this "new" stator is probably way better! [You will need to but a 4 pin regulator that is full wave GY6 engine style].The old coil had string wrapped with the magnet wire, and was kept into place with fabric and some kind of sealant. [Which coil? Was this the ignition power coil? Winding a coil with a combo of wire and string is a classic method to reduce disributed capacitance].
All this is relevant to New CDI.... Right?
#42
Join Date: Dec 2008
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After rereading some of your posts, I might have made a big mistake. I used some sheet metal to customize the ignition coil. I got a sheet and twisted it around the core and made it taller by pounding it flat at the top. So the coil is bigger at bottom and gets smaller and thinner at top. Like this: lL, there is a little bit of a slope and space in the core. I'm not sure about the permeability of the sheet metal (off some carport pipes).
I'm worried about sheet metal being "twisted it around the core". You must not form anything that looks like a shorted turn around the core. Look at the wire topology that you have wound, where the wires go around the core. The spinning magnets generate AC voltages on these wires. If wind another conductor around the core (like a hunk of steel) and the ends short together forming a conductive loop then all power generation stops. All the magnetic flux is used up making enormous current in the shorted turn wrapped aroand the coil. Because it is a short there is no output voltage, so the power is zero. Remember that output power is the product of current times voltage. The current is high but the voltage is zero. Zero volts time any anount of current is still zero power.
I've not looked, but I bet if you examine the core section inside the coils that you would you will find that the core itself is made up of laminated and insulted thin sheets of transformer steel stacked up. This is to keep the core itself from forming a shorted turn. These type of losses are called Eddy Current Losses if you want to look it up.
Another less dramatic loss could be from the added material being reluctant to reverse it's internal magnetic domains (on a molecular level). When forced to do so under a large and alternating magnetic field they dissipate some power which goes up as heat. It's called Hysteresis Losses. The stock core is most likely made from transformer steel (a special steel alloy) that minimizes this hysteresis loss effect.
#43
I got 3 VAC when I tested the stator. So I rewound the coil even tighter and and put some cardboard on the core. I tested it and got ~10 VAC and ~20 VAC at full speed. But that was with only one coil, the one with the core that was originally for charging the battery. Your right about my customized coil core(originally for ignition), I will probably take the sheet metal off and leave as is. I don't think ~10 VAC at idle is going to work. Getting the ignition coil and rewrapping it would probably give me 2-3 more volts so the voltage is a little higher at idle, right (the ignition coil core is 1/4 the size of the battery coil core) ? When I said the ignition switch shuts off the "output" when starting, I meant that the output side of the ignition switch turns off while starting. How do I measure the wattage of this stator?
#44
#45
So I will probably buy another coil core for charging the battery and rewrap it. I guess I might be able to put some extra wraps on this coil which might give a little more voltage. So do you think the best way to regulate this is to get 2 regulators, connect them to each coil, and connect the 2 regulators in parallel? Or I could make a double phase stator!
#46
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[quote=cesar110;3124013]I got 3 VAC when I tested the stator. So I rewound the coil even tighter and and put some cardboard on the core. I tested it and got ~10 VAC and ~20 VAC at full speed. But that was with only one coil, the one with the core that was originally for charging the battery. Your right about my customized coil core(originally for ignition), I will probably take the sheet metal off and leave as is. I don't think ~10 VAC at idle is going to work. Getting the ignition coil and rewrapping it would probably give me 2-3 more volts so the voltage is a little higher at idle, right (the ignition coil core is 1/4 the size of the battery coil core) ? /quote]
I didn't know that the ignition coil side had a smaller core. I've never taken one apart. This is really significant. The core volume is crucial to power generation.
And remember (this is really important), you're not simply trying to generate more voltage. Instead you are attempting to generate power. Note that electrical Power (usually measured in watts) is voltage multiplied times current (for resistive loads like incandescant lights, heaters, etc.).
If your driving things that are capacitive or inductive (like electrical motors) then the math gets a lot more complicated. Don't go there, concentrate on loading your stator output (through the regulator(s) or not) with lights, or other purely resistive loads to keep your life simpler.
So more voltage is not neccesarilly good. Consider the extremes again: If you put 1 million turns on the battery charge winding you would generate a huge voltage at any speed. But you would generate nearly zero current. Zero current times any voltage is zero power. On the other hand if you put just one turn around the core made out formed copper plate that fills up the whole coil volume you would get enormous current, but almost zero voltage . The output current is high but the power is near zero because of the near zero voltage. In between these extremes you get moderate voltage *and* current. At some point in the middle you will find the maximum output power point based on some engine speed (I'd pick 3000 RPM), and the number of turns.
And once again this is difficult to model. You have to experiment. Again this is a major endeavor.
This isn't right. Do you have any links to this switch? Where did you get it?
AC RMS Voltage times AC RMS current for purely resistive loads.
I didn't know that the ignition coil side had a smaller core. I've never taken one apart. This is really significant. The core volume is crucial to power generation.
And remember (this is really important), you're not simply trying to generate more voltage. Instead you are attempting to generate power. Note that electrical Power (usually measured in watts) is voltage multiplied times current (for resistive loads like incandescant lights, heaters, etc.).
If your driving things that are capacitive or inductive (like electrical motors) then the math gets a lot more complicated. Don't go there, concentrate on loading your stator output (through the regulator(s) or not) with lights, or other purely resistive loads to keep your life simpler.
So more voltage is not neccesarilly good. Consider the extremes again: If you put 1 million turns on the battery charge winding you would generate a huge voltage at any speed. But you would generate nearly zero current. Zero current times any voltage is zero power. On the other hand if you put just one turn around the core made out formed copper plate that fills up the whole coil volume you would get enormous current, but almost zero voltage . The output current is high but the power is near zero because of the near zero voltage. In between these extremes you get moderate voltage *and* current. At some point in the middle you will find the maximum output power point based on some engine speed (I'd pick 3000 RPM), and the number of turns.
And once again this is difficult to model. You have to experiment. Again this is a major endeavor.
AC RMS Voltage times AC RMS current for purely resistive loads.
#48
#49
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10 volts AC is 14 volts DC when rectified and filtered. But is this is unloaded. WHen you start drawing current the voltage will drop. Did you ever measure your stock coil? How does that compare?