Fan assembly and control method thereof, and air conditioner

Abstract

The present application provides a fan assembly and a control method thereof, and an air conditioner. The fan assembly comprises a mounting bracket (1), a guide ring (2) and a motor (3) are arranged on the mounting bracket (1), the motor (3) comprises a drive shaft (4), a fan blade (8) is arranged on the drive shaft (4), the fan blade (8) is located in the guide ring (2), and the fan assembly further comprises a control assembly, the control assembly is configured to control the blades located on the lower side of the fan blade (8) to deviate from a vertical plane, the vertical plane passing through the central axis of the drive shaft (4). According to the fan assembly of the present application, the problem of the fan blade hitting the guide ring and being damaged due to the air conditioner falling during transportation can be avoided.

Description

Technical Field

[0001] The present application relates to the technical field of air conditioning, and in particular to a fan assembly and a control method thereof, and an air conditioner. Background Art

[0002] In the current air conditioning market, there is a problem that window air conditioners cannot be used normally due to damaged blades after being used for a period of time. Market research and test verification found that in areas with poor logistics environment, the product is prone to falling during transportation and turnover; at the same time, the design gap between the product blade and the rear partition guide ring is limited by the heat dissipation effect of the condenser, which is generally about 5mm; due to the influence of the blade's own weight, one of the blades naturally points downward when the machine is stopped, and the product is prone to falling multiple times during transportation and turnover, causing the blade to hit the bottom of the guide ring downward and cracks to appear. Summary of the invention

[0003] Therefore, the technical problem to be solved by the present application is to provide a fan assembly and a control method thereof, and an air conditioner, which can prevent the air conditioner from falling during transportation and causing the fan blades to hit the guide ring and be damaged.

[0004] In order to solve the above problems, the present application provides a fan assembly, including a mounting bracket, on which a guide ring and a motor are arranged, the motor includes a drive shaft, on which a fan blade is arranged, and the fan blade is located in the guide ring. The fan assembly also includes a control assembly, and the control assembly is configured to control the blades located on the lower side of the fan blade to deviate from a vertical plane, which passes through the central axis of the drive shaft.

[0005] Preferably, the control component includes a controller and a rotation angle detector, the rotation angle detector is configured to detect the rotation angle of the drive shaft, and the controller is connected to the motor and configured to control the rotation position of the drive shaft according to the rotation angle detected by the rotation angle detector.

[0006] Preferably, a latch position is provided on the drive shaft, and the latch position has a positioning plane. On a plane perpendicular to the central axis of the drive shaft, a line connecting the tip of one of the blades and the central axis of the drive shaft is perpendicular to the positioning plane, and the control component is configured to control the angle between the positioning plane and the horizontal plane.

[0007] Preferably, an inclination sensor is arranged on the positioning plane.

[0008] Preferably, the control component includes a controller and a delayed power-off module. The controller is configured to detect whether the stop position of the fan blade at the bottom deviates from a preset angle of the vertical plane after the fan blade stops rotating naturally, and when the stop position of the fan blade does not deviate from the preset angle of the vertical plane, supply power through the delayed power-off module to drive the fan blade to rotate.

[0009] Preferably, the control component includes a controller and a photoelectric coupler. The photoelectric coupler is arranged at a position of the mounting bracket corresponding to the bottom of the guide ring. The photoelectric coupler is configured to detect whether the blade is located at the bottom of the guide ring and send the detection result to the controller. The controller controls the rotation of the motor according to the detection angle of the photoelectric coupler.

[0010] Preferably, the minimum gap L between the blade and the guide ring satisfies 10 mm≤L≤15 mm.

[0011] Preferably, the control component includes a controller and a counter, the counter is configured to record the number of power-off times of the fan component and send the recorded information to the controller, and the controller releases the control of the rotational position of the blade after the number of power-on and power-off times of the fan component reaches a preset number.

[0012] Preferably, the housing of the motor is fixedly connected to the mounting bracket via a plurality of connecting arms.

[0013] According to another aspect of the present application, an air conditioner is provided, comprising a fan assembly, which is the above-mentioned fan assembly.

[0014] According to another aspect of the present application, a control method for the above-mentioned fan assembly is provided, comprising:

[0015] When the fan blade stops rotating, the position of the blade located at the lower side of the fan blade is detected;

[0016] If the position of the blade deviates from the preset angle of the vertical plane, the current position of the blade is maintained;

[0017] If the position of the blade deviates from the vertical plane and does not reach a preset angle, the rotation position of the blade is adjusted to a target position.

[0018] Preferably, the step of detecting the position of the blade located at the lower side of the wind blade comprises:

[0019] Detecting the rotation angle of the drive shaft;

[0020] Determining whether the drive shaft reaches a target angle according to the detected rotation angle of the drive shaft;

[0021] If the target angle is reached, it is determined that the position of the blade deviates from the preset angle of the vertical plane;

[0022] If the target angle is not reached, it is determined that the position of the blade deviates from the vertical plane and does not reach a preset angle.

[0023] Preferably, the step of detecting the position of the blade located at the lower side of the wind blade comprises:

[0024] Detect the angle between the positioning plane and the horizontal plane;

[0025] If the angle between the positioning plane and the horizontal plane is within the preset angle range, it is determined that the position of the blade deviates from the vertical plane by a preset angle;

[0026] If the angle between the positioning plane and the horizontal plane is not within the preset angle range, it is determined that the position of the blade deviates from the vertical plane by less than the preset angle.

[0027] Preferably, the step of detecting the position of the blade located at the lower side of the wind blade comprises:

[0028] Detect whether the blade located at the bottom blocks the light emitted by the photocoupler;

[0029] If the light emitted by the photoelectric coupler is blocked, it is determined that the position of the blade deviates from the vertical plane by a preset angle;

[0030] If the light emitted by the photoelectric coupler is not blocked, it is determined that the position of the blade deviates from the vertical plane and does not reach a preset angle.

[0031] Preferably, if the position of the blade deviates from the vertical plane and does not reach a preset angle, the step of adjusting the rotation position of the blade to the target position includes:

[0032] If the position of the blade deviates from the vertical plane and does not reach a preset angle, the motor is powered through a delayed power-off procedure, and the rotation position of the blade is adjusted to the target position through the motor.

[0033] Preferably, the control method further comprises:

[0034] Counting the number of power outages of the fan assembly;

[0035] When the number of power failures reaches n, the step of detecting the position of the blade located at the lower side of the fan blade when the fan blade stops rotating is eliminated.

[0036] The fan assembly provided by the present application includes a mounting bracket, a guide ring and a motor are arranged on the mounting bracket, the motor includes a drive shaft, a fan blade is arranged on the drive shaft, and the fan blade is located in the guide ring. The fan assembly also includes a control assembly, and the control assembly is configured to control the blades located on the lower side of the fan blade to deviate from the vertical plane, and the vertical plane passes through the central axis of the drive shaft. The fan assembly controls the blades located on the lower side of the fan blade to deviate from the vertical plane to a preset angle, adjusts the position of the fan blades, and avoids the fan blades being at the bottom of the guide ring when the product is stopped, thereby effectively preventing the bottom of the product from falling multiple times during the transportation turnover process, causing the blades to directly hit the bottom of the guide ring downward and cause damage, and effectively reducing the after-sales complaint rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1This is an exploded structural diagram of a fan assembly according to an embodiment of the present application;

[0038] Figure 2 This is a schematic diagram of the structure of a fan assembly according to an embodiment of the present application;

[0039] Figure 3 This is a schematic diagram of a control method for a fan assembly according to an embodiment of the present application.

[0040] The reference numerals are:

[0041] 1. Mounting bracket; 2. Guide ring; 3. Motor; 4. Drive shaft; 5. Positioning plane; 6. Photoelectric coupler; 7. Connecting arm; 8. Fan blade. DETAILED DESCRIPTION

[0042] See also Figure 1 to Figure 2 As shown, according to an embodiment of the present application, the fan assembly includes a mounting bracket 1, on which a guide ring 2 and a motor 3 are arranged, the motor 3 includes a drive shaft 4, on which a fan blade 8 is arranged, and the fan blade 8 is located in the guide ring 2, and the fan assembly also includes a control assembly, which is configured to control the blades located at the lower side of the fan blade 8 to deviate from a vertical plane, which passes through the central axis of the drive shaft 4. The vertical plane here is relative to the horizontal plane, and the vertical plane is perpendicular to the horizontal plane.

[0043] The fan assembly controls the blades located at the lower side of the fan blade 8 to deviate from the vertical plane to a preset angle, adjusts the position of the fan blades, and avoids the blades of the fan blade 8 being at the bottom of the guide ring 2 when the product is stopped, thereby effectively preventing the bottom of the product from falling multiple times during transportation and turnover, causing the blades to directly hit the bottom of the guide ring 2 downward and cause damage, and effectively reducing the after-sales complaint rate. The preset angle is preferably 30° to 60°, which can make each blade of the fan blade 8 avoid the bottom position of the guide ring 2, improve safety during transportation, and effectively prevent the blades from hitting the bottom of the guide ring 2. The bottom position of the guide ring 2 is close to the chassis, that is, the lowest position of the guide ring 2 in the up and down direction when in use.

[0044] In one embodiment, the control component includes a controller and a rotation angle detector, the rotation angle detector is configured to detect the rotation angle of the drive shaft 4, the controller is connected to the motor 3, and is configured to control the rotation position of the drive shaft 4 according to the rotation angle detected by the rotation angle detector.

[0045] During the process of testing after the product is assembled, the initial position of the drive shaft 4 and the initial position of the fan blade 8 can be recorded, and then the corresponding relationship between the two can be calculated and stored in the controller. In this way, the initial rotation angle of the drive shaft 4 can be obtained, and the rotation position of the fan blade 8 can be determined based on the initial rotation angle of the drive shaft 4 and the relationship between the initial position of the fan blade 8 and the initial position of the drive shaft 4, and then it can be determined whether the blade position of the fan blade 8 meets the requirements. Since one rotation of the drive shaft 4 is a cycle, as long as the initial position of the drive shaft 4 and the number of rotations of the drive shaft 4 are known, the current position of the fan blade 8 when the motor stops can be calculated, and then it can be determined whether there is a blade at the bottom of the guide ring 2, and the final stop position of the fan blade can be adjusted accordingly to avoid the blade being at the bottom of the guide ring 2, forming an effective protection for the fan blade 8 and the guide ring 2.

[0046] In one embodiment, a latch position is provided on the drive shaft 4, and the latch position has a positioning plane 5. On a plane perpendicular to the central axis of the drive shaft 4, a line connecting the tip of one of the blades and the central axis of the drive shaft 4 is perpendicular to the positioning plane 5, and the control component is configured to control the angle between the positioning plane 5 and the horizontal plane.

[0047] In this embodiment, it is only necessary to clearly define the relative position relationship between the positioning surface 5 and the fan blades. By controlling the angle between the positioning surface 5 and the horizontal plane, the final stop position of the motor shaft can be conveniently located, thereby effectively preventing the fan blades 8 from being located at the bottom of the guide ring 2.

[0048] The positioning plane 5 is provided with an inclination sensor, which can directly measure the angle between the positioning plane 5 and the horizontal plane after the fan blade 8 stops, or measure the angle between the positioning plane 5 and the horizontal plane after the speed of the fan blade 8 is reduced to a certain amplitude. After the fan blade 8 stops, if the angle between the positioning plane 5 and the horizontal plane does not meet the requirement, the driving shaft 4 can continue to be controlled to rotate by delay control or adding auxiliary power, so that the fan blade 8 can rotate to the preset position.

[0049] The control component includes a controller and a delayed power-off module. The controller is configured to detect whether the stop position of the fan blade 8 at the bottom deviates from a preset angle of the vertical plane after the fan blade 8 stops rotating naturally, and when the stop position of the fan blade 8 does not deviate from the preset angle of the vertical plane, the delayed power-off module supplies power to drive the fan blade 8 to rotate.

[0050] The control component includes a controller and a photoelectric coupler 6. The photoelectric coupler 6 is arranged at a position of the mounting bracket 1 corresponding to the bottom of the guide ring 2. The photoelectric coupler 6 is configured to detect whether the blade is located at the bottom of the guide ring 2 and send the detection result to the controller. The controller controls the rotation of the motor 3 according to the detection angle of the photoelectric coupler 6.

[0051] When a blade of the fan blade 8 is located at the bottom position, it will block the light emitted by the photoelectric coupler 6. This means that the position of the fan blade 8 has not reached the target position, so the fan blade 8 still needs to be controlled to continue rotating. When the fan blade 8 does not block the rays emitted by the photoelectric coupler 6, it means that the current position of the fan blade 8 can meet the adjustment requirements, and the fan blade 8 can be kept at the current position.

[0052] The minimum gap L between the blade and the guide ring 2 satisfies 10 mm ≤ L ≤ 15 mm, so that the gap between the fan blade 8 and the guide ring 2 can be large enough to effectively prevent the fan blade 8 from hitting the guide ring 2 during transportation.

[0053] The control component includes a controller and a counter. The counter is configured to record the number of power-off times of the fan component and send the recorded information to the controller. When the number of power-on and power-off times of the fan component reaches a preset number, the controller releases the control of the rotation position of the blade.

[0054] After the product enters the user's home and is used normally, there is no need to control the status of the fan blades after shutdown. The number of power outages is designed in the control method design logic. When the number of power outages exceeds 3 times, it will end directly without the need to operate the fan blade control process.

[0055] The housing of the motor 3 is fixedly connected to the mounting bracket 1 via a plurality of connecting arms 7 .

[0056] According to an embodiment of the present application, the air conditioner includes a fan assembly, which is the above-mentioned fan assembly.

[0057] The above-mentioned air conditioner is preferably a window air conditioner.

[0058] See also Figure 3 As shown, according to an embodiment of the present application, the control method of the fan assembly includes: when the fan blade 8 stops rotating, detecting the position of the blade located at the lower side of the fan blade 8; if the position of the blade deviates from the vertical plane by a preset angle, maintaining the current position of the fan blade 8; if the position of the blade deviates from the vertical plane by less than the preset angle, adjusting the rotation position of the blade to the target position. The blade at the lower side of the fan blade 8 refers to the blade at the bottom of the fan blade 8 when the fan assembly is in a stationary state.

[0059] The step of detecting the position of the blade located on the lower side of the fan blade 8 includes: detecting the rotation angle of the drive shaft 4; judging whether the drive shaft 4 reaches the target angle according to the detected rotation angle of the drive shaft 4; if the target angle is reached, judging that the position of the blade deviates from the vertical plane by a preset angle; if the target angle is not reached, judging that the position of the blade deviates from the vertical plane by a preset angle.

[0060] The step of detecting the position of the blade located on the lower side of the wind blade 8 includes: detecting the angle between the positioning plane 5 and the horizontal plane; if the angle between the positioning plane 5 and the horizontal plane is within a preset angle range, it is judged that the position of the blade deviates from the vertical plane by a preset angle; if the angle between the positioning plane 5 and the horizontal plane is not within the preset angle range, it is judged that the position of the blade deviates from the vertical plane by less than a preset angle.

[0061] The step of detecting the position of the blade located at the lower side of the wind blade 8 includes: detecting whether the blade located at the bottom blocks the light emitted by the photoelectric coupler 6; if the light emitted by the photoelectric coupler 6 is blocked, it is judged that the position of the blade deviates from the vertical plane by a preset angle; if the light emitted by the photoelectric coupler 6 is not blocked, it is judged that the position of the blade deviates from the vertical plane by less than the preset angle.

[0062] If the position of the blade deviates from the vertical plane and does not reach the preset angle, the step of adjusting the rotation position of the blade to the target position includes: if the position of the blade deviates from the vertical plane and does not reach the preset angle, powering the motor 3 through a delayed power-off program, and adjusting the rotation position of the blade to the target position through the motor 3.

[0063] The control method further includes: counting the number of power outages of the fan assembly; when the number of power outages reaches n, eliminating the step of detecting the position of the blades located at the lower side of the fan blade 8 when the fan blade 8 stops rotating.

[0064] In one embodiment, after the window air conditioner production line is assembled, the quality control inspector will power on the product for inspection. After a period of power-on operation, the inspector uses the shutdown button on the remote control or control panel to shut down the machine. The stepper motor or servo motor will be powered off and suspend operation. The fan blades 8 will naturally stop rotating after a certain period of time due to inertia. The inertial rotation time will vary with the fan blade speed, and can generally be 30s. The inertial rotation time may not be measured. It is only necessary to operate directly according to the test results after the fan blades 8 stop rotating and the test is completed.

[0065] The controller is designed with a 60-second power-off delay function. After the shutdown button on the remote control or control panel is used to shut down the machine, it will be in the power-off standby state after a delay of 60 seconds. After the machine is shut down for 30 seconds and the fan blade 8 stops rotating, the machine supplies power to the motor through the power supply and prepares to drive the motor. If the positioning plane 5 of the motor bearing pin position is at an angle of 30° to 60° with the horizontal plane, the angle between the blade of the fan blade 8 and the vertical plane passing through the axis of rotation is 30° to 60°, that is, the lowest position of the guide ring is placed between the two blades, then there is no need to rotate the motor, and the fan blade 8 can be kept in this state, and then the machine is powered off and kept in the standby state. If the positioning plane 5 of the motor pin position is not at an angle of 30° to 60° with the horizontal plane, the motor runs clockwise to drive the fan blade to rotate until the positioning plane 5 of the motor socket pin position is at an angle of 30° to 60° with the horizontal plane, the motor stops rotating, and the fan blade 8 is kept in this state at this time, and then the machine is powered off and the motor stops running.

[0066] This control method aims to control the angle between the fan blades 8 and the guide ring 2 to prevent the fan blades 8 from falling to the ground during transportation, causing the fan blades 8 to hit the guide ring 2 and cause the fan blades 8 to be damaged. Therefore, after the product enters the user's home and is used normally, there is no need to control the state of the fan blades after shutdown. The number of power outages is designed in the control method design logic. When the number of power outages exceeds 3 times, it ends directly without the need to operate the fan blade control process.

[0067] In one embodiment, after the window air conditioner production line is assembled, the quality control inspector will power on the product for inspection. After the product has been powered on for a period of time, the inspector will use the power-off button on the remote control or control panel to shut down the product. The stepper motor or servo motor will be powered off and suspended, and the fan blades will naturally stop rotating after the inertia of rotation.

[0068] A pair of photoelectric couplers 6 are installed on the guide ring 2. After the machine is turned off for 30 seconds and the fan blades 8 stop rotating, the machine uses the delayed power-off function to power the motor and the photoelectric coupler 6 through the power supply. When the motor is ready to be driven, if the blades of the fan blades 8 do not block the light emitted by the photoelectric coupler 6, the guide ring 2 is located at the bottom between the two blades at this time, and there is no need to rotate the motor. Let the fan blades 8 maintain this state, and then the machine is powered off and remains in standby state. If the blades of the fan blades 8 block the light emitted by the photoelectric coupler 6, the motor rotates clockwise to drive the fan blades to rotate until the fan blades do not block the photoelectric coupler 6. The photoelectric coupler 6 sends a signal to the controller to stop the motor from rotating and maintain the state of the fan blades at this time. Then the machine is powered off and the motor stops running.

[0069] After the product enters the user's home and is used normally, there is no need to control the status of the fan blades after shutdown. The number of power outages is designed in the control method design logic. When the number of power outages exceeds 3 times, it will end directly without the need to operate the fan blade control process.

[0070] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0071] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application. The above are only preferred implementations of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present application, and these improvements and variations should also be regarded as the protection scope of the present application.

Claims

1. A fan assembly, characterized in that: The invention comprises a mounting bracket (1), on which a guide ring (2) and a motor (3) are arranged, the motor (3) comprises a drive shaft (4), on which a fan blade (8) is arranged, the fan blade (8) is located in the guide ring (2), and the fan assembly further comprises a control assembly, the control assembly being configured to control a blade located on the lower side of the fan blade (8) to deviate from a vertical plane, the vertical plane passing through the central axis of the drive shaft (4).

2. The fan assembly according to claim 1, characterized in that: The control component comprises a controller and a rotation angle detector, wherein the rotation angle detector is configured to detect the rotation angle of the drive shaft (4), and the controller is connected to the motor (3) and is configured to control the rotation position of the drive shaft (4) according to the rotation angle detected by the rotation angle detector.

3. The fan assembly according to claim 1, characterized in that: The drive shaft (4) is provided with a latch position, and the latch position has a positioning plane (5). On a plane perpendicular to the central axis of the drive shaft (4), a line connecting the tip of one of the blades and the central axis of the drive shaft (4) is perpendicular to the positioning plane (5), and the control component is configured to control the angle between the positioning plane (5) and a horizontal plane.

4. The fan assembly according to claim 3, characterized in that: An inclination sensor is arranged on the positioning plane (5).

5. The fan assembly according to claim 1, characterized in that: The control component comprises a controller and a delayed power-off module, wherein the controller is configured to detect whether the stop position of the fan blade (8) located at the bottom deviates from a preset angle of the vertical plane after the fan blade (8) stops rotating naturally, and to supply power through the delayed power-off module to drive the fan blade (8) to rotate when the stop position of the fan blade (8) does not deviate from the preset angle of the vertical plane.

6. The fan assembly according to claim 1, characterized in that: The control component comprises a controller and a photoelectric coupler (6), wherein the photoelectric coupler (6) is arranged at a position of the mounting bracket (1) corresponding to the bottom of the guide ring (2), and the photoelectric coupler (6) is configured to detect whether the blade is located at the bottommost position of the guide ring (2), and send the detection result to the controller, and the controller controls the rotation of the motor (3) according to the detection angle of the photoelectric coupler (6).

7. The fan assembly according to claim 1, characterized in that: The minimum gap L between the blade and the guide ring (2) satisfies 10 mm ≤ L ≤ 15 mm.

8. The fan assembly according to claim 1, characterized in that: The control component includes a controller and a counter, wherein the counter is configured to record the number of power-off times of the fan component and send the recorded information to the controller, and the controller releases the control of the rotational position of the blade after the number of power-on and power-off times of the fan component reaches a preset number.

9. An air conditioner, comprising a fan assembly, characterized in that: The fan assembly is the fan assembly according to any one of claims 1 to 8.

10. A method for controlling a fan assembly according to any one of claims 1 to 8, characterized in that: include: When the fan blade (8) stops rotating, detecting the position of the blade located at the lower side of the fan blade (8); If the position of the blade deviates from the preset angle of the vertical plane, the current position of the fan blade (8) is maintained; If the position of the blade deviates from the vertical plane and does not reach a preset angle, the rotation position of the blade is adjusted to a target position.

11. The control method according to claim 10, characterized in that: The step of detecting the position of the blade located at the lower side of the fan blade (8) comprises: Detecting the rotation angle of the drive shaft (4); determining whether the drive shaft (4) has reached a target angle based on the detected rotation angle of the drive shaft (4); If the target angle is reached, it is determined that the position of the blade deviates from the preset angle of the vertical plane; If the target angle is not reached, it is determined that the position of the blade deviates from the vertical plane and does not reach a preset angle.

12. The control method according to claim 10, characterized in that: The step of detecting the position of the blade located at the lower side of the fan blade (8) comprises: Detecting the angle between the positioning plane (5) and the horizontal plane; If the angle between the positioning plane (5) and the horizontal plane is within a preset angle range, it is determined that the position of the blade deviates from the vertical plane by a preset angle; If the angle between the positioning plane (5) and the horizontal plane is not within the preset angle range, it is determined that the position of the blade deviates from the vertical plane by less than the preset angle.

13. The control method according to claim 10, characterized in that: The step of detecting the position of the blade located at the lower side of the fan blade (8) comprises: Detecting whether the blade located at the bottom blocks the light emitted by the photoelectric coupler (6); If the light emitted by the photoelectric coupler (6) is blocked, it is determined that the position of the blade deviates from a preset angle of the vertical plane; If the light emitted by the photoelectric coupler (6) is not blocked, it is determined that the position of the blade deviates from the vertical plane and does not reach a preset angle.

14. The control method according to claim 10, characterized in that: If the position of the blade deviates from the vertical plane and does not reach a preset angle, the step of adjusting the rotation position of the blade to the target position includes: If the position of the blade deviates from the vertical plane and does not reach a preset angle, the motor (3) is powered through a delayed power-off program, and the rotation position of the blade is adjusted to a target position through the motor (3).

15. The control method according to claim 10, characterized in that: The control method also includes: Counting the number of power outages of the fan assembly; When the number of power failures reaches n, the step of detecting the position of the blade located at the lower side of the fan blade (8) when the fan blade (8) stops rotating is eliminated.

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