Marathon Electric Generators A. Gen-Set is the combination of a synchronous AC generator (alternator) with a prime-mover (usually a diesel or gaseous engine), a fuel system, exhaust system, and gen-set control systems. Marathon Generators manufactures only the electrical generator (alternator) and supplies them as an OEM to the Gen-Set packager. Marathon Generators Catalog Model Search : HOME. Products. Standard Product (by Voltage) Specialty Product Marathon Electric PANCAKE GENERATOR Installation View and Download Marathon Electric PANCAKE GENERATOR installation, operation and maintenance manual online. Reconnect all incoming power leads as shown on wiring diagram. To reassemble the armature, pull main rotor leads through the holes in the exciter rotor.