I think that using sinusoidal AC may not produce a too high output because the derivative of the sine is a co-sine, that has a maximum of 1.0. A very steep current impulse is what is needed to produce very high voltages. Isaac Em 25/11/2012 21:31, Richard Prosser escreveu: > Hi Luis, > > 200 ohms seems very high. 200milli Ohms might be nearer the mark for the > ones I've seen. The voltage generated by the magnet is quite small but yo= u > really want a high current as it's the di/dt that generates the volts. So > the resistance is low. If you can inject a (very) few volts of AC into t= he > primary you should get a clean output on the secondary at a much higher > voltage. Try running a 5V AC supply though the primary in series with a > resistor or lamp and see what open circuit voltage you get on the seconda= ry > with a scope or even an AC voltmeter. Watch where you put your fingers > though! > > RP > > > On 26 November 2012 12:15, Luis Moreira = wrote: > >> Hi Alan, >> The wiring seems correct looking at the colours of the wires, it is a >> pretty simple setup. >> Best Regards >> Luis >> On 25 Nov 2012 22:13, wrote: >> >>> Another possible problem is the primary winding getting wired reverse >>> polarity by someone fiddling with the unit. This will have a serious >> effect >>> on the intensity of the spark, as well as possibly upsetting the timing= .. >> If >>> you have a manual for it check which wire colour should be connected to >>> where. >>> >>> >>>> Hi Luis, >>>> >>>> The primary is likely to be quite low resistance anyway and therefore >>>> may be OK after all. If both ends of the winding are available, check >>>> it hasn't got a short to or earth/frame etc. This is somewhat more >>>> likely than shorted turns, although this is possible. >>>> >>>> Is their a mechanical switch, or is the operation electronic? If >>>> electronic, it can be possible to switch the electronic parts for a >>>> generic switch unit. It's just a matter of finding something suitable = - >>>> ---. >>>> >>>> Capacitor failure is also not unknown and the problem is that it break= s >>>> down under high voltage so looks OK when tested. Replacement is >>>> generally the best test for them. >>>> >>>> If you can borrow parts from a similar unit you should be able to >>>> isolate the problem. >>>> >>>> Magnetos work by interrupting the current in a short-ciruited coil (th= e >>>> primary) which induces a much higher voltage in an overwind (the >>>> secondary). The switching used to be a mechanical switch, but these >>>> days is usually electronic and triggered by measuring some variation i= n >>>> the coil current as the magnet passes. Or by separate sensor in some >>>> cases. >>>> The capacitor provides a bit of control over the resonant frequency >>>> which effects maximum voltage and spark duration. >>>> >>>> RP >>>> >>>> >>>> >>>> >>>> >>>> On 26 November 2012 09:49, Luis Moreira >>>> wrote: >>>> >>>>> parts: ignition coil, >>>>> some sort of pickup and the magneto/cap part that >>>>> >>>> -- >>>> http://www.piclist.com PIC/SX FAQ & list archive View/change your >>>> membership options at http://mailman.mit.edu/mailman/listinfo/piclist >>> -- >>> Scanned by iCritical. >>> >>> -- >>> http://www.piclist.com PIC/SX FAQ & list archive >>> View/change your membership options at >>> http://mailman.mit.edu/mailman/listinfo/piclist >>> >> -- >> http://www.piclist.com PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist >> --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .