Yamaha EF4500iSE Theory & Diagnostics Manual page 17

Generator Information and Theory
EF2800i AC-CDI
The Yamaha EF2800i Inverter generator is the only
generator in the Yamaha line-up to use an AC-CDI.
A CDI unit which uses AC power to charge the con-
denser is referred to as an AC-CDI.
Taking the low voltage power generated by the
charge coil (which is wound around a single stator
core in the multi-polar alternator), a voltage booster
circuit boosts the voltage in the CDI in order to
charge the condenser. In a typical CDI system, volt-
age of approximately 200~400 volts is generated by
the charge coil.
The advantages are the charge coil can be made
both lighter and smaller. Also a heavier wire can be
used for the charge coil to increase its reliability.
An overrun limiter is incorporated into the EF2800i's
AC-CDI unit.
The ignition spark is regulated to prevent engine
speed overrun when the engine speed exceeds
4500 rpm.
A new oil warning system was designed to match
the new CDI system, while maintaining the same
function of the conventional oil warning system.
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