Abstract: A fan motor speed control circuit is disclosed. The circuit includes a digital/analog converting unit and a driving unit. The digital/analog converting unit takes charge of receiving a pulse width modulation (PWM) signal and converting it into a voltage signal. The driving unit is connected with the digital/analog converting unit in series for receiving the voltage signal, while the driving unit provides a first predetermined voltage level and a second predetermined voltage level as references. The fan motor is kept to run with a low constant rotation speed when the voltage signal level is higher than the first predetermined voltage level, with a full constant rotation speed when the voltage signal level is lower than the second predetermined voltage level, and with a variable rotation speed when the voltage signal level is lower than the first predetermined voltage level and higher than the second predetermined voltage level.

Abstract: A moisture-proof device is provided to be used in a fan having a stator for isolating the stator from moisture. The moisture-proof device includes a first covering part for covering a circuit board of the stator of the motor, and a second covering part connected to the first covering part for covering a coil and a core of the stator of the motor, thereby isolating the stator of the motor from moisture, wherein the first covering part and the second covering part are integrally formed as a single piece, wherein the moisture-proof device is disposed in a hub of the fan.

Abstract: A motor rotor. The motor rotor adapted to be used in a fan includes a hub, a metal plate and a magnet. The metal plate has a first end and a second end. The metal plate is disposed in the hub. The magnet is disposed in the metal plate.

Abstract: An impeller is applied to a centrifugal fan and includes fan blades and a hub. Each fan blade includes a first portion and a second portion. The first portion is located relatively close to the hub and the first portion is coupled to the second portion. The first portion has a windward side and a leeward side, and the windward side is parallel to the leeward side. The second portion is located relatively far away from the hub. The second portion has a windward side and a leeward side, and the windward side and the leeward side are two curved surfaces with different specific curvatures.

Abstract: A fan is disclosed for use in a system, and the system has at least one connection structure. The fan is mainly composed of an impeller and a base, and the impeller is connected to the base. The impeller at least has a hub, a plurality of blades and a driver. The base has at least one engaging member, and the engaging member is corresponding to the connection structure. Further, the fan is fixed on the system by connecting the engaging member and the connection structure together.

Abstract: A driving circuit for switches of direct current fan motor is disclosed. The driving circuit includes a plurality of switches, a first control circuit, and a second circuit. The switches are driven by a first pulse width modulation signal and a second pulse width modulation signal, and they are electrically connected with the direct current fan motor in a bridge manner. A third pulse width modulation signal is used to drive the first control circuit connected to at least one of the switches driven by the first pulse width modulation signal. A fourth pulse width modulation signal is used to drive the second control circuit connected to at least one of the switches driven by the second pulse width modulation signal. Especially, either the first pulse width modulation signal or the second pulse width modulation signal is selected as the third pulse width modulation signal or the fourth pulse width modulation signal.

Abstract: An overvoltage protective device for DC motor is disclosed. The device includes a voltage-dividing circuit and a control unit, and is electrically connected to a DC motor in parallel. The voltage-dividing circuit has one end thereof electrically connected to an input voltage of the DC motor, and the other end thereof grounded. The control unit is electrically connected to a part of the voltage-dividing circuit for accessing a voltage level thereof and thereby driving the DC motor.

Abstract: The non-biasing guiding mechanism related to CD-R drives is used to drive a data access device to move along a particular direction and to access the data on a CD. The shaft of the non-biasing guiding mechanism is fixed by an axis-fixing member. The axis-fixing member has ring parts on the opposite ends and a receiver integrally formed with the ring part in a concentric way. The ring part is coiled by a coil and sets inside the drive, and the hole is used for positioning the shaft and sets outside the drive. Therefore, the biasing problem of the shaft can be solved by using the axis-fixing member.

Abstract: A heat-dissipating device and a housing thereof. The heat-dissipating device includes an impeller and a housing. The impeller includes a hub and a plurality of rotor blades disposed around the hub. The housing includes an outer frame, an air-guiding part, and a plurality of stator blades. The air-guiding part is formed on at least one side of the outer frame. The stator blades are disposed in the outer frame corresponding to the air-guiding part. The stator blades guide the airflow through the blades, and greatly increase the static pressure of the airflow discharged from the heat-dissipating device.

Abstract: A PWM buffer circuit includes a duty cycle converting circuit and a frequency-fixed PWM signal generating circuit. The duty cycle converting circuit is used for receiving a first PWM signal and then generating a duty cycle reference voltage on the basis of the first PWM signal. The duty cycle reference voltage is a one-to-one mapping function of the first duty cycle. The frequency-fixed PWM signal generating circuit is used for receiving the duty cycle reference voltage and then outputting a second PWM signal with a fixed frequency. The second PWM signal has a second duty cycle, which is determined in accordance with the duty cycle reference voltage. In addition, the second duty cycle is a one-to-one mapping function of the duty cycle reference voltage.

Abstract: A coupling structure for a tandem motor includes two bearing sleeves formed with grooves thereon, a connector and elastic fasteners. The connector has a first end and an opposed second end, and each of the first end and second end is formed with at least one groove. A first elastic fastener is fit into the groove of the connector at the first end and received in the groove formed on one of the two bearing sleeve, and a second elastic fastener is fit into the groove of the connector at the second end and received in the grooves formed on the other bearing sleeve.

Abstract: A fan control system. The fan control system has a programmable microcontroller to receive an input signal and a rotation speed signal corresponding to the actual rotation speed of the fan motor, determining an output signal according to the input signal and the rotation speed signal, and outputting the output signal; and a fan-driving unit to receive the output signal and adjusting the rotation speed for driving the fan motor according to the output signal. The rotation speed is in a relation of a multi-stage function to the input signal.

Abstract: The invention provides a heat-dissipating assembly and a securing device used therein, which utilizes a way of securing by applying force in one direction to prevent the surface of a chip from being damaged. The securing device includes a frame body having a plurality of first fasteners fastened to a socket by the first fasteners; and a wrenching member pivotally coupled to the frame body, wherein after applying an external force on the wrenching member in one direction, the heat-dissipating device can be fixed tightly on the socket.

Abstract: A fastening device is used to tightly attach the heat sink on an electronic element. The fastening device includes an elastic arm, a first latch element and a second latch element. The elastic arm has a first axial part, a second axial part, and a press part. The first latch element is secured to one side of the socket for mounting the electronic element thereon and pivotally coupled to the first axial part, and the second latch element is pivotally coupled to the second axial part. As the elastic arm turns about the first latch element and crosses the heat sink, the second latch element is allowed to be fastened onto another side of the socket. Thus, the press part of the elastic arm would urge against the heat sink to enable the heat sink to be tightly attached on the electronic element.

Abstract: An outer-rotor type brushless fan motor is provided, wherein the outer edge of a stator of the outer-rotor type brushless fan motor is surrounded in the cup-shaped outer periphery of a rotor case of a rotor thereof, and the rotor is rotated with respect to the stator. The outer-rotor type brushless fan motor is characterized in that at least one projection and a corresponding opening thereof are formed on a surface of the rotor case, so that the projection and the corresponding opening thereof are rotated together with the rotation of the rotor, thereby heat generated by the stator is dissipated.

Abstract: A fastening structure for securing a stator of a motor includes a sleeve with a cut portion formed thereon and a fastener. The fastener is composed of a position section and an engaging section, wherein the engaging section engages with the cut portion and the position section presses on the top surfaces of the coil bobbin of the stator.

Abstract: The heat-dissipating module includes at least one heat-dissipating device and a terminal mounted and fixed on one side of the heat-dissipating device and electrically connected with the heat-dissipating device. As the heat-dissipating module is inserted into a frame of the system, the terminal will be received by a receptacle inside the system such that the heat-dissipating module can be electrically connected to the system. The heat-dissipating module can be easily dissembled and replaced in a system without turning off the system and can provide the best heat-dissipating efficiency in a limited space of the system without being affected by the inside height or thickness of the system.

Abstract: A fan motor structure includes a fan base, a bearing assembly, a fan hub and a shaft. The fan hub is formed with an extrusion protruding from its top planar surface, and the shaft is fit into the bearing assembly and connected to the fan hub. The shaft has one end protruding from the top planar surface of the fan hub to form an extension portion, and the extension portion of the shaft is enclosed by and in close connection with the extrusion of the fan hub.

Abstract: A heat dissipation module with twin centrifugal fans is described. The heat dissipation module is utilized in an electrical equipment and especially for a computer server system. The heat dissipation module has a honeycomb panel, a first fan, an air duct, a second fan and a plurality of sliding rails. The honeycomb panel connects with an outlet of the first fan and an out of the air duct in the rear side thereof. The first fan sucks hot air from the underside thereof and exhausts the hot air to the outside through the honeycomb panel. The second fan sucks hot air from the underside thereof and exhausts the hot air to the outside through the honeycomb by way of the air duct. The sliding rails configure along the two sides of the first fan and the second fan.

Abstract: The present invention discloses a fan protection apparatus and related method thereof. The fan protection apparatus has a control circuit and a counter. According to the fan protection method, the user can set the acceptable restart number and the special time for auto restart. The fan protection apparatus and method can force to stop the fan when the fan encounters an abnormal situation. When the stop time has passed, the fan is automatically restarted. The present invention counts the number of restarts.