D
duivendyk
Guest
In a recent post I explained how CDI ignition systems work,this info was based on the CDI's as found in Honda mopeds & scooters.I stated there that I was not familiar with what was exactly in the Chinese engines.
After looking around in the forums I concluded that their system may not be a CDI setup, after all,but a sort of distributed quasi magneto based affair.
There is an ignition module that supplies the spark,which interfaces with the engine power coil in the flywheel and is probably just an ignition stepup transformer,nothing more.
The ignition module has a ground connection (black),and a power coil connection (blue) from the flywheel generator, which energizes the coil's primary,the output is the HV ignition pulse to the plug.
The reason it cannot be a CDI module is that it lacks the essential trigger pulse connection from the engine flywheel.With the kill switch (blue & red wires) the input to the coil can be shorted to ground,killing the engine.What then about the "white" mystery wire coming out of the engine which people have used to power lights with.Good question,my best guess:it's a "tap"on the power coil, supplying a lower voltage ac. output and can be used to kill the engine like the blue wire but in a safer way.With some diodes & savvy you could probably charge a battery with it,without messing up the ignition
The RFI (radio frequency interference) attributes of this allovertheplace ignition setup are pretty bad, but not dangerous as some people who could not get their digital multimeters to work, were concerned about.(Unless you are fool enough to grab onto the bare "blue wire")
These instuments are broadband and use sample& hold techniques which make them quite vulnerable to any kind of interference.The best way to protect them in this polluted environment is the following:twist the test leads around one another as much as possible and put a capacitor across the meter input as close as possible( 0.1 to 1 microfarad,preferably a ceramic cap).An ancient technology analog meter will probably work a lot better.
I could give some pointers on how to reduce EMI, if anyone caress to know,most of what people come up with (ferrite beads copper jackets etc) is quite ineffective when dealing mainly with low frequency stray magnetic fields,as is the case here.
MBC EDIT: THIS THREAD HAS BEEN MOVED
After looking around in the forums I concluded that their system may not be a CDI setup, after all,but a sort of distributed quasi magneto based affair.
There is an ignition module that supplies the spark,which interfaces with the engine power coil in the flywheel and is probably just an ignition stepup transformer,nothing more.
The ignition module has a ground connection (black),and a power coil connection (blue) from the flywheel generator, which energizes the coil's primary,the output is the HV ignition pulse to the plug.
The reason it cannot be a CDI module is that it lacks the essential trigger pulse connection from the engine flywheel.With the kill switch (blue & red wires) the input to the coil can be shorted to ground,killing the engine.What then about the "white" mystery wire coming out of the engine which people have used to power lights with.Good question,my best guess:it's a "tap"on the power coil, supplying a lower voltage ac. output and can be used to kill the engine like the blue wire but in a safer way.With some diodes & savvy you could probably charge a battery with it,without messing up the ignition
The RFI (radio frequency interference) attributes of this allovertheplace ignition setup are pretty bad, but not dangerous as some people who could not get their digital multimeters to work, were concerned about.(Unless you are fool enough to grab onto the bare "blue wire")
These instuments are broadband and use sample& hold techniques which make them quite vulnerable to any kind of interference.The best way to protect them in this polluted environment is the following:twist the test leads around one another as much as possible and put a capacitor across the meter input as close as possible( 0.1 to 1 microfarad,preferably a ceramic cap).An ancient technology analog meter will probably work a lot better.
I could give some pointers on how to reduce EMI, if anyone caress to know,most of what people come up with (ferrite beads copper jackets etc) is quite ineffective when dealing mainly with low frequency stray magnetic fields,as is the case here.
MBC EDIT: THIS THREAD HAS BEEN MOVED
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