Hello,
LCI stands for Load Commutated Inverter. In a nutshell, it drives the generator as a motor used for starting the turbine and helping it get to rated speed.
the LCi is powered by 4160 (2080 wye and 2080 delta) it is then rectified to DC power to eliminate harmonics and inverted back to linear 4160 AC to the generator stator. The LCI AC feeds into the stator and the exciter produces a magnetizing flux to the field in order to motor the system. The generator's neutral must be lifted at this time. The LCI then breaks the unit from turning gear speed and at about 50% speed the turbine breaks away and takes over the unit to 3600rpms'. During the break away period, the LCI's voltgae and field current decreses since the turbine is taking over. at about 95% speed the LCI totally drops out.
refer to the GEK for more info. This LCI is like a huge VFD in my mind, driving the synchonous motor (generator/turbine coupled).
hope this sparks your interest!