AC voltage measured at Minarelli magneto

Hey, I've disconnected the 3 wires coming off the Minarelli V1 mag. Then spinning the engine over, I am only getting 1 volt off the blue wire and the white wire. I am thinking it should be more like 6 volts, 5 anyway. You think?

Re: AC voltage measured at Minarelli magneto

Louis Brunskill /

Spinning it fast?

Re: AC voltage measured at Minarelli magneto

You're measuring between the two wires?

Re: AC voltage measured at Minarelli magneto

Negative. Checking them one at a time. From the white wire to ground. Then checking the blue wire to ground with a professional quality Fluke VOM. Spinning the engine with a Ryobi electric drill.

With my NC50 Express, for example, I can release the spring starter and read almost 6 VAC from either the lighting or the ignition coil. Similarly, I can disconnect the alternator on my Africa Twin and spin that over with the electric starter and read 85 VAC from all three phases.

So I would assume I should be able to see 6 VAC at the flywheel alternator (magneto) of the Minarelli. Unless of course I have a major voltage drop somewhere which is entirely possible. I haven't really dug very deep into this project bike yet. I was just doing some initial troubleshooting, like checking the operation and timing of the points with a buzz box.

Re: AC voltage measured at Minarelli magneto

with the lead disconnected from the rest of the bike you can only have voltage loss in one place and that's right in the winding of the coil. I never put much faith in an electric drill spinning an engine. Even at idle the engine is spinning far faster than most drills will turn it. I would guess most drills will not even turn 1000 RPM while the average idle of a moped will be 15 to 1800. Still The one volt does seem somewhat low.

Re: AC voltage measured at Minarelli magneto

the voltage should be RPM dependent and usually set to make peak volts at peak rpm that way now blowing bulbs. later setups use a regulator so you make more power all around and just cut off what the excess so you've got more consistent lights. Or they add in a battery, but that's more the scootery noped ones.

I dunno though I've never actually measured the power.

you can short the windings if it overheated or if the flywheel ever scraped the sizing off the wires.

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