Before revision: In order to produce the proper voltage at a constant AC frequency, usually three-phase 115 VAC at 400 Hz, a generator needs to spin at a constant specific speed (typically 6,000 RPM for air-cooled generators).
After revision: In order to produce the proper voltage at a constant AC frequency, usually three-phase 115 VAC at 400 Hz, an alternator needs to spin at a constant specific speed (typically 6,000 RPM for air-cooled generators).