Abstract: A driving circuit has a driving circuit module, a rotation rate detecting module and a rotation status detecting module. The driving circuit module is used to drive an AC fan motor and has at least a driving IC having two controlling outputs and a rotation status detecting output. The rotation rate detecting module has a transistor and an photo coupler. The transistor is connected to one of the two controlling outputs of the driving IC. The photo coupler is connected to the transistor and outputs a rotation rate signal to compute the rotation rate of the AC fan motor. The rotation status detecting module has an photo coupler connected to the rotation status detecting output of the driving IC and outputting a rotation status signal to determine whether the AC fan motor operates normally.

Abstract: A DC brushless fan motor driving circuit has a Hall PWM signal generator, a speed signal generator, a PWM driver and a full-bridge switching circuit. The Hall PWM signal generator obtains a Hall sine wave signal from an external Hall sensor and converts the Hall sine wave signal to a varied Hall PWM signal. The speed signal generator is connected to an external PWM input signal to set speed of a fan motor and a low speed voltage to determine a present speed setting signal. The speed signal generator further obtains the varied Hall PWM signal to compare the present speed setting signal to generate a SPWM signal to the PWM driver. The PWM driver outputs a SPWM signal to the full-bridge switching circuit and then coil current is formed close to a sine wave signal to decrease the electromagnetic noise.

Abstract: A magnetic force sensing device for a brushless motor includes a drive circuit board mounted inside the casing and located below the stator, a Hall element electrically connected to the drive circuit board, an annular magnet mounted on a rotor casing and located outside the stator, and a magnetic force conducting plate having an area larger than that of the Hall element and being mounted below the drive circuit board to sandwich the Hall element with the annular magnet. Due to the addition of the magnetic force conducting plate below the magnet, magnetic flux from the magnet to the Hall element is increased.

Abstract: A fan with a function of far infrared ray emission has a shell, a circuit board mounted in the shell, a stator, a rotator, at least one far infrared radiator. The far infrared radiators will emit far infrared ray, which is further spread with the airflow caused by the rotation of the rotator.

Abstract: A driving circuit of an AC fan motor has an AC to DC converter, a current detecting unit, a step-down divider, a motor driving unit, two windings each having many coils and a harmonic wave elimination unit. The AC to DC converter converts AC power to high voltage DC power. The motor driving unit is connected to the step-down divider to obtain low voltage DC power to operate. The two windings are directly connected to the AC to DC converter through the current wave detect unit to obtain the high voltage DC power. Therefore, the current wave detecting unit can response current changes of windings and then an operator can simulate present current wave of the windings to determine the present operating status of the AC fan motor.

Abstract: A driving circuit of an AC fan motor has an AC to DC converter, a current detecting unit, a step-down divider, a motor driving unit, two windings each having many coils and a harmonic wave elimination unit. The AC to DC converter converts AC power to high voltage DC power. The motor driving unit is connected to the step-down divider to obtain low voltage DC power to operate. The two windings are directly connected to the AC to DC converter through the current wave detect unit to obtain the high voltage DC power. Therefore, the current wave detecting unit can response current changes of windings and then an operator can simulate present current wave of the windings to determine the present operating status of the AC fan motor.

Abstract: A shaft sleeve of a DC brushless fan has a cylindrical body, an upper space, a lubricant cavity, a recess, a partition and a longitudinal outer edge. The upper space is formed in the top of the cylindrical body. The lubricant cavity is defined in the cylindrical body and communicates with the upper space. The recess is defined in the bottom. The partition is formed inside of the cylindrical body and between the lubricant cavity and the recess. The longitudinal outer edge is formed around the recess. When the longitudinal outer edge of the shaft sleeve is pressed into a through hole in a frame, a force is generated in the longitudinal outer edge to securely hold the longitudinal outer edge in the frame. Therefore, a strength of a joint between the shaft sleeve and the frame is increased.

Abstract: A DC brushless fan motor driving circuit has a Hall PWM signal generator, a speed signal generator, a PWM driver and a full-bridge switching circuit. The Hall PWM signal generator obtains a Hall sine wave signal from an external Hall sensor and converts the Hall sine wave signal to a varied Hall PWM signal. The speed signal generator is connected to an external PWM input signal to set speed of a fan motor and a low speed voltage to determine a present speed setting signal. The speed signal generator further obtains the varied Hall PWM signal to compare the present speed setting signal to generate a SPWM signal to the PWM driver. The PWM driver outputs a SPWM signal to the full-bridge switching circuit and then coil current is formed close to a sine wave signal to decrease the electromagnetic noise.

Abstract: A retaining device has a retaining belt and a handle pivotally connected with the retaining belt and having an arcuate portion and a flat portion. When the handle pivots relative to the retaining belt and when the arcuate portion engages the heat sink, the engagement between the heat sink and the socket will be enhanced. When the flat portion engages the heat sink, the engagement between the heat sink and the socket will be loosened.