Abstract: A power-take-off (PTO) electrical generator system for mechanically driving a rotary screw type air compressor employed in a space-confined environment of a utility truck, includes: a controller mounted to a portion of an existing utility truck, a PTO operably coupled to an existing engine of the existing utility truck as well as the controller, an electrical generator located at the existing utility truck and operably coupled directly to and driven by the PTO, an air compressor directly coupled to and mechanically driven directly by the electrical generator and located at a space-confined section of the existing utility truck, and a cooling fan assembly located at the existing utility truck and directly coupled to the air compressor. The electrical generator is intermediately positioned between the PTO and the air compressor.