Abstract: A drive unit for a carrier that includes a chassis with a drive wheel that is pivotable with an air spring in and out of contact with a surface over which the carrier is propelled. The air spring is in a pneumatic system including an air compressor which is connected to a processor in an electrical system. The compressor is programmed to provide a fair safe mode for the drive wheel, a runtime control for the air compressor and a battery voltage sensing circuit to shut down the electrical system during periods of inactivity.

Abstract: A regulator provides a control signal for controlling a generator which is providing an electrical output. The electrical output includes an output voltage and an output current applied to a load. The regulator comprises a microprocessor, voltage sensing inputs and current sensing inputs which cooperate with the microprocessor to sense a parameter of the electrical output applied to the load and a first memory for storing predetermined parameters. The microprocessor compares the sensed parameter to its corresponding predetermined parameter stored in the first memory and generates an output signal representative of the comparison. The regulator further comprises a second memory for storing instructions for controlling operation of the microprocessor and generates the control signal as a function of the output signal from the microprocessor.