The AC electrical system consists of __ generators and __ GCUs (Ground Control Units). Generators are mounted on and are driven by the XMSN __. Each one can supply __ electrical power. The GCUs manages __ to satisfy electrical power requirements. After the APU is started at __%RPM, GCU energizes primary bus contactor. It provides generator protection by disconnecting generator for the following: Undervoltage (__+-__VAC or less) Overvoltage (__+-__VAC or more), underfrequency, overcurrent, and feeder __ between the generator output and system loads.