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A
correctly timed spark is the system's ultimate goal. It starts with a
magnet, generating coil and adds some electronics which help generate the
high voltage and time the events. Timing cues come from the magnet's
position on a flywheel or other disc.
Some
systems provide an output for charging batteries, too. Usually they do
this by placing additional generating coils around the flywheel.
Generating coils are relatively low voltage but create a fair amount of
current.
The
diagram at right is a simplification since it does not show the
electronics, usually buried inside the coil unit, to make it work. Two
electrical concepts are used: 1) suddenly stopping current flow in a coil
produces a high voltage in the coil and 2) running a changing current flow
through a coil with few windings will induce a much larger voltage in a
nearby coil with more windings.
Essentially,
the guts do the following. All the electricity gathered from the
generating coil gets put under great electrical pressure (voltage) then
fired in a brief, well-timed pulse to the spark plug.
The
Kill Switch shorts out the generating coil. That prevents the generating
coil from sending anything to the rest of the system and is why the kill
switch involves relatively low voltage. You won't get much shock even if a
kill wire gets exposed. |
Simplified
paramotor ignition system. |
|
Here
are the most common causes of failure to spark.
1.
The most likely cause of ignition problems is the spark plug. At $2 a copy
replacing it is also the easiest, cheapest thing to do. Sometimes a motor
can defy your most fervent corrective efforts when all it wanted was a new
plug. Plugs can look surprisingly perfect--the right color, no visible
cracks, shiny metal, etc and still be bad. If in doubt, toss it out.
2.
Next up is the spark plug cap, namely those where the cap screws into the
plug wire (most of them). It's easy to mis-thread and not get firmly
enmeshed in wire. It may work if its barely touching the wire but may
cause intermittency problems. Those are the worst--a part-time problem.
3.
The kill switch wire that goes from the coil out to your throttle button
cannot touch any metal. If it does, it's just like pressing the kill
switch--the motor will not run.
4.
If you have replaced any part of the motor requiring removal of the
flywheel or magnet, then you must insure they're returned to their proper
home.
Thanks
to Nick Scholtes for helping with technical details and research |
These
cheap caps can cause problems, especially if the screw-in portion is not
seated in the wire. |
