GEC 2, 4, 7 & 11 Thyristor Controlled Adjustable-speed drives. Operator's Instruction and Technical Manual GEC Gemini 2, 4, 7 and 11 Thyristor Controlled Adjustable-speed drives. Operator's Instruction and Technical Manual with Electrical Schematics. Manufacturers: GEC Models: 11 2 4 7 Gemini Contents: Operators Manual Electrical Diagrams