Abstract: Motors comprising stators and rotors having a plurality of north poles and south poles and methods of controlling the same. A first sensor and a second sensor are provided. The first and second sensors are disposed on the stator in a manner that the first and second sensors never simultaneously detect boundaries between the north and south poles during rotation of the rotor. If any one of the first and second sensors continuously detects a north pole or a south pole for a predetermined duration, the motor is shut off.

Abstract: A heat dissipation device and fan module. The fan module is fixed to a fan tray, which has a track with a first engaging portion. A securing member is disposed on a shield, comprising a second engaging portion. The second engaging portion enters the first engaging portion, fixing the fan module to the fan tray. An actuator connects the securing member and the shield. When external force deforms the actuator, the securing member deforms therewith, withdrawing the second engaging portion from the first engaging portion.

Abstract: A hot swap fan includes a fan and a holding member. The fan has an air inlet, an air outlet, and a sidewall connected between the air inlet and the air outlet. The holding member is bent to form a top portion and at least one side portion and affixed on the sidewall. The top portion is formed with at least one handle portion, and part of the side portion is formed as a movable flexible portion connecting to the handle portion. The flexible portion is formed with an engaging structure to engage a casing that accommodates the hot swap fan.

Abstract: A fan and a rotor structure thereof. The rotor structure has a case, an upper linking structure, a lower linking structure, and a shaft. The case has an opening at the axle center. The upper linking structure has a fixing portion and a threaded portion. The minimum radius of the fixing portion is longer than the radius of the opening. The threaded portion is disposed in the opening. The lower linking structure has a thread corresponding to the threaded portion. The upper linking structure and the lower linking structure is screwed together to secure the case therebetween. The shaft is fixed in the upper linking structure or the lower linking structure.

Abstract: A motor control circuit includes a pulse width modulation (PWM) signal generating circuit, a driving circuit and a waveform-shaping circuit connected between the PWM signal generating circuit and the driving circuit. The PWM signal generating circuit generates a square wave with a sequence of alternating on-time and off-time. The waveform-shaping circuit adjusts the rise-time and the fall-time of the square wave to be both within a range of 5% to 15% of the square wave period, and the driving circuit outputs a driving signal to a fan motor according to the adjusted square wave.

Abstract: A connecting device of a hot swap fan module comprises at least one terminal and a casing. The at least one terminal is electrically connected to the fan so that, when the fan is mounted in a system, electrical connection is formed between the fan and the system. The connecting device further comprises at least one LED (light emitting diode) which is electrically connected to the fan or the at least one terminal for indicating the operating state of the fan, and at least one cover plate protruded from at least one edge of the casing so as to form the whole casing into an L or U-shaped structure. The casing is closely attached to one side face of the fan housing when the casing is assembled to the fan. The casing also has a recess for receiving those lead wires electrically connecting the terminals, the fan, and the LED.

Abstract: A motor speed control device. The motor speed control device applied to a direct current (DC) fan includes a driving element constituted by a driving IC and Hall IC, a thermal sensor and a control element electrically connected between the driving element and the thermal sensor. The present invention utilizes a thermal sensor and a simple control element to effectively and stably control the variable speed of the fan within different temperature ranges.

Abstract: A modified mounting structure for a heat-dissipating device. The heat-dissipating device has a motor and a seat with a slot mounted on a base or the cover portion of a stator thereof. The seat secures a motor controller of the heat-dissipating device detecting phase changes of the magnetic poles of the motor. The structure of a heat-dissipating device reduces required components, manufacturing cost and assembly time, and the control circuit is greatly simplified.

Abstract: A motor having a magnetic bearing. The motor includes a base provided with a bearing seats, a stator fixed to the base, a rotor equipped with a rotation shaft and able to rotate relative to the stator by magnetic forces generated from excitation, a bearing fastened to the bearing seat of the base for accommodating the rotation shaft of the rotor, and a magnetic unit composed of a first, a second and a third magnetic elements. The second magnetic element is located below the first magnetic element. The third magnetic element is located below the second magnetic element. By employing the magnetic force, the second magnetic element is restrained between the first and third magnetic elements, thereby limiting a shift range of the rotation shaft.

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 fan speed control circuit includes a pulse width modulation (PWM) signal generating circuit, a driving circuit and a phase compensation unit. The PWM signal generating circuit generates a PWM control signal with a sequence of alternating on-time and off-time, and the driving circuit outputs a driving signal according to the PWM control signal to a fan motor. The phase compensation unit is connected to the fan motor for delaying or advancing the PWM control signal by a phase angle to synchronize the acting period of the back electromotive force formed by the magnetic flux variation with the off-time of the PWM control signal.

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 thermal control variable-speed circuit without switching noise is connected with a driving circuit, which controls the rotation speed of a fan motor using a driving voltage. The thermal control variable-speed circuit includes a reference voltage output circuit and a driving voltage control circuit. The reference voltage output circuit outputs a corresponding reference voltage signal according to ambient temperature changes. The reference voltage output circuit has one end connected to a first resistor in series and to a second resistor in parallel. The driving voltage control circuit outputs a corresponding driving voltage according to the magnitude of the reference voltage signal.

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: A motor structure includes a stator and a rotor. The stator includes a coil assembly which includes a ring-shaped slot having an inner periphery on its inner side and an outer periphery on its outer side away from the inner periphery, a plurality of first teeth mounted around the inner periphery of the ring-shaped slot, and a plurality of second teeth mounted around the outer periphery of the ring-shaped slot; wherein each of the first teeth is arranged to partly fall behind or exceed the corresponding one of the second teeth, and a coil wound in the ring-shaped slot. The rotor includes a circular magnet located above the coil.

Abstract: A motor structure is disclosed. The motor structure includes a stator and a rotor. Among these, the stator further includes a coil seat defined by a bottom plate, a plurality of first teeth and a plurality of second teeth. A coil is formed in the coil seat. The first teeth formed around inner periphery of the bottom plate and have a first extending portion extending so as to constitute a reversed L shape. The second teeth formed around outer periphery of the bottom plate and have a second extending portion so as to constitute a reversed L shape. The rotor, coupled to the stator, further have a circular magnet formed above the coil seat, the first extending portion and the second extending portion. Each of the first and second extending portions further includes a chamfer, a fillet, a clearance, a fold and different dimension.

Abstract: A centrifugal fan having an upside-down mounted structure and being mounted on a heat-dissipating plate includes a frame fixed on the heat-dissipating plate and a stator upside-down mounted in the frame and fixed on the upper surface. The frame includes an upper surface positioned away from the heat-dissipating plate, a side surface substantially perpendicular to the upper surface, at least one inlet formed on the upper surface, and an outlet formed on the side surface. The stator includes a printed circuit board positioned close to the upper surface and positioned away from the heat-dissipating plate.

Abstract: A motor having a magnetic bearing includes a base provided with a bearing seat; a stator fixed to the base; a rotor equipped with a rotation shaft and is able to rotate relative to the stator by magnetic forces generated from excitation; a bearing fastened to the bearing seat of the base for accommodating the rotation shaft of the rotor; and a magnetic unit composed of a first, a second and a third magnetic elements, wherein the second magnetic element is located below the first magnetic element; the third magnetic element is located below the second magnetic element. By employing the magnetic force, the second magnetic element is restrained between the first and third magnetic elements, thereby limiting a shift range of the rotation shaft.

Abstract: A motor structure including a stator having a coil assembly, and a rotor having a circular magnet located above the coil. The stator includes a coil assembly having a ring-shaped slot, a plurality of first teeth, a plurality of second teeth, and a coil. The ring-shaped slot has an inner periphery on its inner side and an outer periphery on its outer side away from the inner periphery. The plurality of first teeth is mounted around the inner periphery of the ring-shaped slot. The plurality of second teeth is mounted around the outer periphery of the ring-shaped slot. The coil is wound in the ring-shaped slot.

Abstract: The present invention discloses a self-stabilizing heat exhaust system including at least several rate-variable fans. Each of the rate-variable fans further includes a power-input terminal for inputting power to the rate-variable fans; a grounded terminal for providing the rate-variable fan a lower level; a signal-output terminal coupled to an adjacent rate-variable fan for outputting a speed signal which may be a normal signal or an abnormal signal; a signal-input terminal coupled to another adjacent rate-variable fan for receiving the speed signal; and a control circuit responding to the abnormal signal to make the rate-variable fan rotate at the higher rotation rate and responding to the normal signal to make the rate-variable fan rotate at the lower rotation rate.