A homopolar machine produces an axial counter force on the rotating shaft to compensate for the load on the shaft’s thrust bearing to reduce wear and noise and prolong bearing life. Integrating the removable plate in or on the casing facilitates access to the medium and the data stored on the medium by providing storage in a location that is convenient and local to the processor-based device. To remove the ash from the particulate filter, ash atomization processing for rendering the state of the particulate filter a state where the exhaust gas which flows into the particulate filter is lowered in concentration of oxygen and the particulate filter is raised in temperature is temporarily performed.