I am in the process of designing some electronics and I am looking at power sources for my application. I am thinking about attempting to take power from the primary side of a transistorized magneto ignition coil as can be found on the honda GX160 engines.
My electronic device runs at 3.3v so I need to some how take this AC current, do some rectifying, smoothing and regulation to generate a nice low ripple DC voltage of 3.3v. The power requirements are fairly small, I only need around 200mA maximum
Does anybody know the typical output voltage and current I would expect from the ignition on something similar to a honda GX160 engine? Power electronics isn't my speciality, I have done some reading up on the subject but am still uncertain about exactly what I need to do!
There is no battery on the primary side. The GX160 unit I was planning on using starts with a recoil pull start and so has no battery.
There is a bullet connector available to me on the primary side of the coil, I don't have access to the engine yet, so ideally I need to know what voltage/current levels I will get from this connector?
Hai there Steven, My name's Dilip George and I could say that I have been into electronics for a long time.First I need to know what is a Honda GX160 engine?.Is it the engine on a bike or a portable generator or something like that?.The point is,if its of a bike,then chances are very good that you will have other windings on the magneto to work on.One winding will be a VERY high voltage coil and is meant for and can be safely used ONLY for the transistorised (electronic) ignition.There could be another winding for the headlamps and one more winding to charge the battery on the bike.Usually, the horn,the brake lights and indicators are run on the battery.In this case we have a fairly clean source of DC (maybe 6volts or 12volts) from which it would be very easy to use a simple transistorized voltage regulator to get the voltage you need.But then,some bikes don't have a battery and run everything from the magneto.But even here there will be a regulator because otherwise all the bulbs will just burn out at high rev.The voltage after this regulator is really FULL of ripple but you can easily put a capacitor to smooth it.Just remember that you'll need to have a diode in between the regulator and capacitor so that you have an isolation from the rest of the gadgets connected to the regulator.From here too you can get the voltage you need through a simple transistorized regulator.BUT if its not a bike engine, but just a stand-alone engine,then it is very tricky because there would be only one winding on the magneto and that too would be the high voltage one.I would never recommend taking a voltage from there.If my guess is right,you are considering using 3.3volts for a microprocessor chip or something like that.Do you see any way that you could add one more coil on the magneto?.Even if there isn't,you could just try and wind a few turns of good grade enamelled copper wire over the existing winding so as to get atleast 6volts AC and then take it on from there.This is also not a recommendable idea if you are meaning to use a microprocessor because a lot of spikes can turn up in there each time the spark-plug fires.I know very well that I havn't answered you question as yet, but then,I can just give you some ideas to work on.If you need more help,please feel free to write and ask.But in the meantime,you have some homework to do.Good luck Steven.
I'd expect mostly nothing with peaks to few hundered volts when the points open... and then less than 100v until they close again, detainls speed dependant, a real mess. I'd be considering putting a second pickup near the flywheel to pick up some better behaved power with less risk of messing up the ignition system or frying the micro.
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