Airflow from a blower fan can be adjusted between a cooling air mode where cooling air flows freely to the ambient surroundings and a noise mode where the airflow is partially or fully restricted in order to produce different levels of soothing background noise. The airflow from the fan can be split or divided between varying degrees and combinations of unrestricted airflow, partially restricted airflow and fully restricted airflow to produce a wide range of cooling airflows into the ambient with or without the production of additional background noise. A perforated drum surrounds the fan to form a chamber within which airflow can resonate at various frequencies and amplify noise levels selected by rotating the drum around the fan.

A compressor is provided. The compressor according to the present disclosure includes: one or more impellers suctioning and compressing refrigerant; a motor rotating the impeller; a rotation shaft to which the impeller and the motor are connected; a gap sensor measuring a displacement change of the rotation shaft as a frequency change; a temperature compensation sensor determining a frequency compensation value according to a temperature change around the gap sensor; and a control unit calculating a displacement amount of the rotation shaft by reflecting the frequency compensation value provided by the temperature compensation sensor and the frequency change measured by the gap sensor.

A fan frame body structure includes a first frame body. The first frame body has a first upper end, a first lower end, a first frame wall and a first main flow way. The first main flow way passes through the first frame body and is formed with a first main inlet and a first main outlet respectively at the first upper end and the first lower end. A first subsidiary flow way is disposed in the first frame wall. The first subsidiary flow way is in parallel the first main flow way. The first subsidiary outlet is positioned at the first upper end of the first frame body in flush with and in adjacency to the first main inlet.

An electronic system includes a fan module, an embedded controller, an error microphone, an active noise cancellation controller, and a micro speaker module. The error microphone is configured to output an error signal by detecting the noise level during the operation of the electronic system. According to the error signal and the fan information provided by the embedded controller, the active noise cancellation controller calculates the narrow-band noises associated with the actual single-blade fundamental frequency noise and the actual BPF fundamental frequency noise generated by the fan module, and drives the micro speaker module accordingly for providing a noise cancellation signal. The error signal may be reduced to zero by adaptively adjusting the noise cancellation signal for canceling the noises generated during the operation of the electronic system.

A fan frame body structure includes a first frame body. The first frame body has a first upper end, a first lower end, a first frame wall and a first main flow way. The first main flow way passes through the first frame body and is formed with a first main inlet and a first main outlet respectively at the first upper end and the first lower end. A first subsidiary flow way is disposed in the first frame wall. The first subsidiary flow way is in parallel the first main flow way. The first subsidiary outlet is positioned at the first upper end of the first frame body in flush with and in adjacency to the first main inlet.

A waterproof fan according to an embodiment of the present invention includes: a blade module configured to be operated by a motor; and a frame having an accommodation hole that accommodates the blade module, the frame being formed to surround the accommodation hole, and the frame includes an opening that opens a part of the accommodation hole.

Provided is a reversible fan that produces a current of air in both of a normal direction and a reverse direction, the reversible fan including: an impeller configured to be rotatable about a rotation axis; a motor configured to rotate the impeller; a base portion supporting the motor; a tubular frame housing the impeller, the motor, and the base portion; a spoke extending from an inner peripheral surface of the frame toward the rotation axis, the spoke supporting the base portion; and a holding portion configured to hold at least a part of a lead wire provided along the spoke to apply power to the motor, wherein the holding portion is provided with a housing space opening in the reverse direction and extending along the spoke.

Provided is a reversible fan including: a fin configured to produce a current of air in both of a normal direction and a reverse direction; an impeller configured to be rotatable about a rotation axis; a motor configured to rotate the impeller; and a tubular frame housing the impeller and the motor, wherein the fin has a shape that allows producing louder noise upon producing the current of air in the normal direction than upon producing the current of air in the reverse direction, and protrudes inward in a radial direction from an inner peripheral surface of the frame.

A method for controlling a fan in a fan start-up stage including a first time period and a second time period comprises the following steps of: during the first time period, continuously providing a first driving signal to drive the fan; and during the second time period, continuously providing a second driving signal to drive the fan; wherein, the signal value of the first driving signal gradually decreases until being equal to the signal value of the second driving signal. Wherein the signal value of the first driving signal non-linearly decreases, the signal value of the second driving signal is an unchanged value. Wherein, the first time period and the second time period are adjusted for a different fan but the sum of the first time period and the second time period is always the same. A fan is also disclosed.

Provided is a reversible fan that produces a current of air in both of a normal direction and a reverse direction, the reversible fan including: an impeller configured to be rotatable about a rotation axis; a motor configured to rotate the impeller; a base portion supporting the motor; a tubular frame housing the impeller, the motor, and the base portion; a spoke extending from an inner peripheral surface of the frame toward the rotation axis, the spoke supporting the base portion; and a holding portion configured to hold at least a part of a lead wire provided along the spoke to apply power to the motor, wherein the holding portion is provided with a housing space opening in the reverse direction and extending along the spoke.