Abstract: An impeller includes a hub, a plurality of blades coupled with the hub, and a plurality of ribs connected to the plurality of blades. Each of the plurality of ribs has a connecting end coupled with the hub. Each of the plurality of blades intersects with at least one of the plurality of ribs.

Abstract: A centrifugal fan includes a fan frame, a motor, an impeller and an axial positioning member. The fan frame includes a base plate portion, a cover plate portion, and a lateral wall portion arranged between the base plate portion and the cover plate portion. The cover plate portion includes an air inlet, and the lateral wall portion includes an air outlet. The motor is received in the fan frame. The impeller is rotatably coupled with the motor. The axial positioning member is arranged along a path surrounding the air inlet of the fan frame. The axial positioning member includes a coupling face and an abutting face opposite to the coupling face. The coupling face is coupled with the cover plate portion of the fan frame. The abutting face is spaced from the coupling face.

Abstract: A motor circuit with power-off braking function includes a driving unit, a coil unit, and a braking unit. The driving unit includes a plurality of switch arms connected in parallel, with each switch arm having a series contact. The coil unit includes a plurality of coils and a central contact. Each coil includes an end connected to the series contact of one of the switch arms. The other end of each coil is connected to the central contact. The braking unit includes a brake loop switch coupled between the central contact of the coil unit and an end of the switch arms. When power is cut off, a plurality of brake loops is formed to share the transient current during braking.

Abstract: A centrifugal fan includes a fan frame, a motor, an impeller and an axial positioning member. The fan frame includes a base plate portion, a cover plate portion, and a lateral wall portion arranged between the base plate portion and the cover plate portion. The cover plate portion includes an air inlet, and the lateral wall portion includes an air outlet. The motor is received in the fan frame. The impeller is rotatably coupled with the motor. The axial positioning member is arranged along a path surrounding the air inlet of the fan frame. The axial positioning member includes a coupling face and an abutting face opposite to the coupling face. The coupling face is coupled with the cover plate portion of the fan frame. The abutting face is spaced from the coupling face.