Patent ID: 7432675

Claim:
A method of operating an apparatus for use with a computer, the computer including a power source, a system board, coupled to the power source and disposed within the computer, on which an electrical component, which controls operations of the computer, is installed, and a heat sink including a plurality of heat transfer surfaces which are configured to contact the electrical component and to thereby remove heat from the electrical component, the method comprising: operating a fan reversing control card, which is coupled to the system board, to generate normal and reverse cycle rotation signals in predetermined intervals; installing a single fan within the computer and coupling the fan to the fan reversing control card via a four-wire cable, the four-wire cable being configured to operate according to a method comprising: carrying a voltage between the fan and the fan reversing control card, carrying a ground voltage between the fan and the fan reversing control card, transmitting, between the fan and the fan reversing control card, a tachometer output signal by which the fan signals an actual speed of rotations of the fan during the normal and reverse cycles of the fan, and transmitting, between the fan and the fan reversing control card, a pulse width modulation (PWM) signal by which the fan reversing control card, which compares the actual speed of rotation with a desired speed, transmits normal and reverse cycle rotation signals to the fan as speed-up, slow-down, normal and/or reverse cycle initiating instructions; and controlling the fan, which is coupled to the fan reversing control card, by receiving the normal and reverse cycle rotation signals from the fan reversing control card, and respectively operating the fan, in accordance with the receiving of the normal and reverse cycle rotation signals, in normal and reverse cycles, in which the fan rotates in first and second directions, respectively, wherein: the method further comprises positioning the installation of the single fan within the computer sufficiently proximate to the heat transfer surfaces such that the first and second directional rotations of the fan generate air flows in first and second directions with respect to the heat transfer surfaces, respectively.