HYBRID AMPLIFICATION OF HIGH SPOOL MOTORING VIA LOW SPOOL POWER EXTRACTION AND MOTORING OF A DIFFERENTIAL GEARED GENERATOR

A power extraction and amplification system (200; 400; 500; 600; 700) for a gas turbine engine (20) is disclosed. In various embodiments, the power extraction and amplification system (200; 400; 500; 600; 700) includes a low spool tower shaft (204; 404; 504; 604) configured for engagement with a low speed spool (30), a high spool tower shaft (202; 402; 502; 602) configured for engagement with a high speed spool (32), a first motor (242; 442; 542; 642), a generator (266; 466; 566; 666), a differential gear box operably coupled to the low spool tower shaft (204; 404; 504; 604), to the first motor (242; 442; 542; 642) and to the generator (266; 466; 566; 666), and a second motor (270; 470; 570; 670) operably coupled to the generator (266; 466; 566; 666) and the high spool tower shaft (202; 402; 502; 602).