This paper highlights the basic concepts and
advantages of More/All Electric Aircraft （MEA/AEA) in the
area of aircraft industry. MEA is anticipated to optimize the
aircraft performance, reduce the total cost and increase safety,
reliability and robustness. The Combined Starter/Generator
（CS/G） system is advised as a key technology to enable
MEA/AEA. A detailed analysis for the performance
requirements of CS/G system is carried out. A comparative study
for different machine candidates for CS/G is proposed, while
focusing on Fault-tolerance, reliability and robustness.