Condenser, battery vs magneto
- Thread starter Tonymanx
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Jack Ryan
Well-known member
I don't believe so, they both have the same function and operate under similar voltages. About 0.2uF
Jack
Jack
nadogail
Well-known member
I thought the purpose of using a magneto was to get away from points and a condenser.
Jack Ryan
Well-known member
It depends on the ignition system. In a lawnmower, perhaps there are no points (and therefore no capacitor). Otherwise, for more precise timing, there are.
Jack
PopcornSutton
Well-known member
The only magneto I'm familiar with was on our old Allis-Chalmers tractor. It had the built in coil and a spring mechanism that spun the mag quickly for each fire. It had the typical points and condensor. The coils went bad often, so people would mount a car coil and run a plug wire in to the rotor. Our tractor had electric start so the battery was there. Some models didn't have starters other than the hand crank, and thus the snap spin of the coil. But that was 1940s stuff.
Magneto is a self sufficient ignition source, no battery required
nadogail
Well-known member
Agreed
Recoveryman
Well-known member
I think the original reason for magnetos was to eliminate the need for batteries and generators, both are expensive items.
Recoveryman
micromind
Well-known member
Aircraft piston engines use magnetos with points and condensers.
A magneto is more reliable than a battery ignition system. Points are still necessary to trigger the coil. And Points require a condenser. Of course modern power equipment like chain saws use electronic ignition, but still use a magneto.
theoldwizard1
Well-known member
All small one and two cylinder engines built in the past 30-40 years (?) use an "electronic" magneto system. There is an extra small coil inside the ignition coil that triggers a transistor that fires the primary side of the main coil. These last a LONG time and so do spark plugs !
Firebrick43
Well-known member
it was the other way around. High tension magnetos existed before battery ignition.
Battery ignition provides much better spark and better timing which is why nearly all automobiles and tractors got away from it in the 40's/early 50's.
Even though battery ignition provides a better/hotter spark and better control air craft still use them generally due to the weight savings compared having two completely separate electrical systems for redundancy if they used a battery ignition. Batteries are heavy.
How ever many new piston powered aircraft, including new cessna 172 can be had with electronic ignition.
Electronic CDI ignition that has generating capacity off the flywheel is NOT a magneto. unless your a wikipedia kind of guy.
They don't have the impulse coupling that magnetos have in them
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You may want to look into top fuel cars. They all run 2 magnetos that put out 44 amps to each spark plug. That's a lot more than any battery current supplied distributor does.
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Firebrick43
Well-known member
Seriously? That is the example you are going to use? Maybe you missed the part about the "40's/early 50's"You may want to look into top fuel cars. They all run 2 magnetos that put out 44 amps to each spark plug. That's a lot more than any battery current supplied distributor does.
And its not a high tension magneto which is what we were talking about.
Its a rare earth magnet generator (which didn't exist in those years) and is entirely electronic in function/timing. Further more it consumes the spark plugs by the end of the 1/4 mile. Real usable on a daily driver there bud
Top fuel cars also make 10-11k hp. Pretty cool but also completely useless in the real world
Jack Ryan
Well-known member
The simple single cylinder (and perhaps two cylinder as well) engines use a magneto without points.
The magneto consists of a magnet connected to the flywheel which triggers a single coil pickup. This creates a pulse in the primary of the ignition coil which, via the secondary, causes the spark. These systems fire twice, once on the compression stroke (the important one) and once on the exhaust stroke (of a 4 stroke).
Yes, there is a Darlington transistor as well but that does not change the principle of operation.
Jack