A rotation locking system of a motor of a fan is provided. A closed-loop control circuit outputs an initial duty cycle signal according to a current rotational speed and a target rotational speed. A driver circuit outputs a driving signal to the motor to drive the motor to rotate according to the initial duty cycle signal. A lookup table arithmetic circuit looks up, from a lookup table, two reference duty cycles correspond to two reference rotational speeds that are respectively equal to the current rotational speed and the target rotational speed. The lookup table arithmetic circuit calculates a difference between the two reference duty cycles. A speed feedback control circuit compensates the initial duty cycle signal according to the difference to output a final duty cycle signal to the driver circuit. The driver circuit drives the motor to rotate according to the final duty cycle signal.

A rotation locking system of a motor of a fan is provided. A closed-loop control circuit outputs an initial duty cycle signal according to a current rotational speed and a target rotational speed. A driver circuit outputs a driving signal to the motor to drive the motor to rotate according to the initial duty cycle signal. A lookup table arithmetic circuit looks up, from a lookup table, two reference duty cycles correspond to two reference rotational speeds that are respectively equal to the current rotational speed and the target rotational speed. The lookup table arithmetic circuit calculates a difference between the two reference duty cycles. A speed feedback control circuit compensates the initial duty cycle signal according to the difference to output a final duty cycle signal to the driver circuit. The driver circuit drives the motor to rotate according to the final duty cycle signal.

In one example, a centrifugal fan includes a bearing, a shaft rotatably supported by the bearing, fan blades operatively connected to and rotatable with the shaft to take in air axially and to exhaust air radially, and a groove in the shaft extending axially along an outer surface of the shaft through the bearing.

The air compressor includes: a housing assembly, wherein the housing assembly has a first installation cavity, a second installation cavity and a rotation-shaft cooperating cavity, and the first installation cavity has a gas inlet and a gas outlet; a rotor shaft, wherein the rotor shaft is rotatably fitted inside the rotation-shaft cooperating cavity, and extends into the first installation cavity and the second installation cavity; a pressure wheel, wherein the pressure wheel is nested to the rotor shaft and is located inside the first installation cavity, and the housing assembly is provided with a controlling flow channel for communicating the gas-intake side and the wheel-back side of the pressure wheel; and a driving assembly, wherein the driving assembly is nested to the rotor shaft and is located inside the second installation cavity.

The fuel cell control system includes: a reactor; an air compressor, wherein the air compressor has a compressing cavity, the compressing cavity has a gas inlet and a gas outlet, a rotatable pressure wheel is disposed inside the compressing cavity, and the gas outlet is in communication with the reactor; a control flow channel, wherein a first end of the control flow channel is in communication with the gas-intake side of the pressure wheel, a second end of the control flow channel is in communication with the wheel-back side of the pressure wheel, and the control flow channel is provided with a return valve for regulating the flow rate of the control flow channel; and a central control unit, wherein the central control unit is communicatively connected to the return valve to control the opening degree of the return valve.

A rotating device and a vacuum pump are provided, having a structure in which a refrigerant or the like does not leak out to an inside and which can sufficiently cool a rotating body, obtain high reliability, and realize cost reduction. The structure is constituted to include: a casing; a rotating body including a rotating shaft disposed rotatably relative to the casing, the rotating body constituted integrally with the rotating shaft; a hollow part formed along a center of the rotating shaft in the rotating body; and a cooling rod which is fixed to the casing and provided in a state of non-contact with the rotating body in the hollow part without having a mechanism for injecting a refrigerant, and which absorbs a radiation heat of the rotating body to cool the rotating body.

A rotating device and a vacuum pump are provided, having a structure in which a refrigerant or the like does not leak out to an inside and which can sufficiently cool a rotating body, obtain high reliability, and realize cost reduction. The structure is constituted to include: a casing; a rotating body including a rotating shaft disposed rotatably relative to the casing, the rotating body constituted integrally with the rotating shaft; a hollow part formed along a center of the rotating shaft in the rotating body; and a cooling rod which is fixed to the casing and provided in a state of non-contact with the rotating body in the hollow part without having a mechanism for injecting a refrigerant, and which absorbs a radiation heat of the rotating body to cool the rotating body.

A motor includes a stator core having an annular shape, a coil wound around a tooth of the stator core, a first terminal electrically connected to the coil, a housing that houses the first terminal, and a second terminal at least partially inserted into the first terminal housed in the housing. The second terminal includes an electrical connecting portion inserted into the first terminal and electrically connected to the first terminal. The housing includes a first restricting portion that restricts movement, in a circumferential direction of the stator core, of a portion of the second terminal other than the electrical connecting portion.

A motor includes a stator core having an annular shape, a coil wound around a tooth of the stator core, a first terminal electrically connected to the coil, a housing that houses the first terminal, and a second terminal at least partially inserted into the first terminal housed in the housing. The second terminal includes an electrical connecting portion inserted into the first terminal and electrically connected to the first terminal. The housing includes a first restricting portion that restricts movement, in a circumferential direction of the stator core, of a portion of the second terminal other than the electrical connecting portion.

Embodiments of this application provide a centrifugal pump. The centrifugal pump includes a pump casing and a first drive mechanism, a second drive mechanism, a pump shaft, and an impeller that are disposed in the pump casing. The pump casing includes a first chamber and a second chamber that are connected. An axis of the pump shaft coincides with axes of the first chamber and the second chamber. An inner diameter of the second chamber is greater than that of the first chamber. The impeller is connected to an end of the pump shaft. The first drive mechanism and the second drive mechanism are connected to the pump shaft and located on a side, away from the impeller, of the pump shaft. The first drive mechanism is configured to drive the pump shaft to rotate.