A method for powering a system in a vehicle, the method including the steps of mechanically coupling, driving and controlling. The mechanically coupling step includes coupling a power unit with at least one primary load, the at least one primary load including a propulsion load. The driving step includes driving a cleaning fan and a cleaning shoe with at least one power source, the at least one power source being mechanically independent from the power unit. The controlling step includes controlling a speed of the at least one power source independent of a speed of the power unit.