Abstract: A fan management system includes a fan and a server. The fan includes a driving circuit, and the driving circuit is configured for driving the fan. The fan operates in an operation mode. The server is connected to the fan and is configured for controlling the operation of the fan. The driving circuit outputs a digital label signal when the fan operates abnormally, and the server obtains a production history, an operation information and a warning message of the fan through the digital label signal. The server adjusts the operation mode of the fan according to the warning message simultaneously.

Abstract: A contra-rotating fan structure includes a first base, a first fan, a second base, and a second fan. The first fan is rotatably disposed on the first base and includes a first hub. The first hub has a first largest width. The second fan is rotatably disposed on the second base and includes a second hub. The second hub has a second largest width. The first base and the second base are located between the first fan and the second fan. The second largest width is greater than the first largest width.

Abstract: A fan control device for controlling a fan includes a communication-processing processor, a fan-controlling processor, and a detection processor. The communication-processing processor receives a fan-controlling instruction from an external system to generate a control signal, generates a detection signal according to a detection request of the external system, and provides state information for the external system. The fan-controlling processor controls the speed of the fan according to the control signal and transmits a control result to the communication-processing processor. The detection processor detects the ambient state and the fan state of the fan according to the detection signal, and generates the state information according to the ambient state and the fan state. The communication-processing processor, the fan-controlling processor, and the detection processor are physically separated from one another.

Abstract: A contra-rotating fan structure includes a first base, a first fan, a second base, and a second fan. The first fan is rotatably disposed on the first base and includes a first hub. The first hub has a first largest width. The second fan is rotatably disposed on the second base and includes a second hub. The second hub has a second largest width. The first base and the second base are located between the first fan and the second fan. The second largest width is greater than the first largest width.

Abstract: A fan control device for controlling a fan includes a communication-processing processor, a fan-controlling processor, and a detection processor. The communication-processing processor receives a fan-controlling instruction from an external system to generate a control signal, generates a detection signal according to a detection request of the external system, and provides state information for the external system. The fan-controlling processor controls the speed of the fan according to the control signal and transmits a control result to the communication-processing processor. The detection processor detects the ambient state and the fan state of the fan according to the detection signal, and generates the state information according to the ambient state and the fan state. The communication-processing processor, the fan-controlling processor, and the detection processor are physically separated from one another.

Abstract: A fan is provided. The fan includes a first power terminal, a second power terminal, a filter, a motor driver, a motor, a current sensor, and a controller. The filter includes an amplifying element, a resistor, and a capacitor, wherein a first terminal of the amplifying element is electrically connected to the first power terminal, a second terminal of the amplifying element is electrically connected to a first terminal of the resistor, and the capacitor is electrically connected between the second power terminal and a third terminal of the amplifying element. The motor is electrically connected to the third terminal of the amplifying element. The current sensor detects the current flowing through the motor and correspondingly generates a current sensing signal. The controller outputs a first control signal to the resistor according to the current sensing signal such that the amplifying element operating in an active region.

Abstract: The invention provides a monitor circuit, which is used for a fan and receives a driving current and a driving voltage of the fan. The monitor circuit includes sensing circuits and a microcontroller. The sensing circuits respectively sense statuses of the fan and output sensing values. The microcontroller is used for monitoring whether the sensing values exceed preset value ranges respectively to obtain comparison results. The microcontroller outputs warning signals according to the comparison results. Each of the warning signals has a specific frequency.

Abstract: The invention provides a monitor circuit, which is used for a fan and receives a driving current and a driving voltage of the fan. The monitor circuit includes sensing circuits and a microcontroller. The sensing circuits respectively sense statuses of the fan and output sensing values. The microcontroller is used for monitoring whether the sensing values exceed preset value ranges respectively to obtain comparison results. The microcontroller outputs warning signals according to the comparison results. Each of the warning signals has a specific frequency.

Abstract: A power-protection apparatus is provided. The apparatus includes an over-voltage protection unit for generating an over-voltage detection signal when the power supply of the load is over the upper limit of a predetermined voltage range; an under-voltage protection unit for generating an under-voltage detection signal when the power supply of the load is under the lower limit of the predetermined voltage range; a working-state detection unit for receiving a control signal and generating a working-state detection signal when the level time-change rate of the control signal is over a time-change rate threshold; and a power-control unit coupled to the over-voltage protection unit, the working-state detection unit and the under-voltage protection unit for controlling the on and off of the power supply according to the over-voltage detection signal, the under-voltage detection signal or the working-state detection signal.

Abstract: A motor control system is disclosed. The motor control system includes a level-shifting unit, a motor unit and a control unit. The level-shifting unit receives an original pulse width modulation (PWM) signal to generate an output PWM signal. When a first high level of the original PWM signal is larger than a first reference value, the level-shifting unit shifts a second high level of the output PWM signal to a set high level. When a first low level of the original PWM signal is lower than a second reference value, the level-shifting unit shifts a second low level of the output PWM signal to a set low level. The control unit controls the speed of the motor according to the output PWM signal.

Abstract: A rotor structure of a fan includes a bushing, a hub, a shaft and a plurality of blades. The hub has a top portion and a sidewall, and the top portion of the hub covers the bushing. The hub and the bushing are made by the same material. One end of the shaft is connected to the bushing, and the shaft is disposed inside the top portion. The blades are disposed on the outer side of the sidewall of the hub. A manufacturing method of the rotor structure is also disclosed.

Abstract: A fan is provided. The fan includes a first power terminal, a second power terminal, a filter, a motor driver, a motor, a current sensor, and a controller. The filter includes an amplifying element, a resistor, and a capacitor, wherein a first terminal of the amplifying element is electrically connected to the first power terminal, a second terminal of the amplifying element is electrically connected to a first terminal of the resistor, and the capacitor is electrically connected between the second power terminal and a third terminal of the amplifying element. The motor is electrically connected to the third terminal of the amplifying element. The current sensor detects the current flowing through the motor and correspondingly generates a current sensing signal. The controller outputs a first control signal to the resistor according to the current sensing signal such that the amplifying element operating in an active region.

Abstract: A control method of a fan rotation speed, which controls the operation of a fan set including fans connected in series, is disclosed. The control method includes the steps of acquiring a control factor; judging whether the control factor is less than a first threshold value; executing a first control procedure when the control factor is less than the first threshold value; judging whether the control factor is greater than a second threshold value when the control factor is greater than the first threshold; executing a second control procedure when the control factor is greater than the second threshold value; and executing a third control procedure when the control factor is less than the second threshold value.

Abstract: An embodiment of the invention provides an AC motor that is driven by an AC voltage. The AC motor includes a motor coil, a switch circuit, a position detector and a controller. The motor coil receives the AC voltage to drive an axis of the motor. The switch circuit is coupled to the motor coil and controls a current passing through the motor coil. The position detector detects the position of a motor rotor to output a polarity signal. The controller controls the switch circuit according to the polarity signal and the AC voltage to make the current to be a first current with a first direction or a second current with a second direction.

Abstract: A fan control device for controlling a fan includes a communication-processing module, a fan-controlling module, and a detection module. The communication-processing module receives a fan-controlling instruction generated by an external system to generate a control signal, generates a detection signal according to a detection request of the external system, and provides state information for the external system. The fan-controlling module controls the speed of the fan according to the control signal and transmits a control result to the communication-processing module. The detection module detects the ambient state and the fan state of the fan according to the detection signal, and generates the state information according to the ambient information and the fan state. The communication-processing module, the fan-controlling module, and the detection module are physically separated from one another.

Abstract: An embodiment of the invention provides an AC motor that is driven by an AC voltage. The AC motor includes a motor coil, a switch circuit, a position detector and a controller. The motor coil receives the AC voltage to drive an axis of the motor. The switch circuit is coupled to the motor coil and controls a current passing through the motor coil. The position detector detects the position of a motor rotor to output a polarity signal. The controller controls the switch circuit according to the polarity signal and the AC voltage to make the current to be a first current with a first direction or a second current with a second direction.

Abstract: A voltage-level shift apparatus includes a first level shift unit, a second level shift unit, a charging unit, and a discharging unit. The first level shift unit receives a reference voltage and a power voltage to output a level-shifting voltage. The second level shift unit is connected to the first level shift unit and receives the level-shifting voltage. The charging unit receives a control voltage to provide an output voltage. The discharging unit is connected to the charging unit and receives the control voltage and the reference voltage. When the control voltage turns on the charging unit and turns off the discharging unit, the charging unit is charged by the level-shifting voltage. When the control voltage turns off the charging unit and turns on the discharging unit, the discharging unit is discharged from the output voltage.

Abstract: A fan control method includes the steps of: acquiring a control factor; determining whether the control factor is located in a first range or a second range; executing a first dust removing mode if the control factor is located in the first range; executing a second dust removing mode if the control factor is located in the second range; and executing a normal mode if the control factor is not located in the first range and the second range.

Abstract: A rotor structure of a fan includes a bushing, a hub, a shaft and a plurality of blades. The hub has a top portion and a sidewall, and the top portion of the hub covers the bushing. The hub and the bushing are made by the same material. One end of the shaft is connected to the bushing, and the shaft is disposed inside the top portion. The blades are disposed on the outer side of the sidewall of the hub. A manufacturing method of the rotor structure is also disclosed.

Abstract: A motor control system is disclosed. The motor control system includes a level-shifting unit, a motor unit and a control unit. The level-shifting unit receives an original pulse width modulation (PWM) signal to generate an output PWM signal. When a first high level of the original PWM signal is larger than a first reference value, the level-shifting unit shifts a second high level of the output PWM signal to a set high level. When a first low level of the original PWM signal is lower than a second reference value, the level-shifting unit shifts a second low level of the output PWM signal to a set low level. The control unit controls the speed of the motor according to the output PWM signal.