Control circuit and control method of dual-speed fan
By designing a two-speed fan control circuit with four contactors, the problem of changing the control circuit in the existing technology is solved, and efficient and safe operation is achieved when replacing the fan, avoiding the wrong wires, saving cost.
Patent Information
- Application Number
- CN202210924602.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-08-02
- Publication Date
- 2024-12-20
- Estimated Expiration
- 2042-08-02
AI Technical Summary
The existing two-speed fan control circuit needs to be replaced when replacing the fan, which is time-consuming and labor-intensive and prone to the wrong wire connection problem.
A control circuit for a two-speed fan is designed, and the structure of four contactors is adopted. The control of different types of two-speed fans is achieved through different contactor combinations to avoid changing the control circuit and ensure correct wiring.
The operation of replacing the fan without replacing the control circuit is realized, avoiding the problem of connecting the wrong wire, improving operating efficiency and safety, and saving costs.
Smart Images
Figure CN115450941B_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the technical field of dual-speed fans, and in particular to a control circuit and a control method for a dual-speed fan. Background Art
[0002] Two-speed motors are mainly used in coal mining, oil and gas, petrochemical and chemical industries. In addition, they are also widely used in textile, metallurgy, city gas, transportation, grain and oil processing, papermaking, medicine and other sectors. As the main power equipment, two-speed motors are usually used to drive pumps, fans, compressors and other transmission machinery. Two-speed motors belong to asynchronous motors with variable pole speed regulation. It changes the number of magnetic poles of the stator rotating magnetic field by changing the connection method of the stator winding, thereby changing the speed of the motor.
[0003] However, one type of two-speed fan corresponds to one control circuit. When the control circuit is fixed, only one type of fan can be selected. If two different types of fans are used, the control circuit must be changed when the fan is replaced. Therefore, switching between different types of fans is time-consuming and laborious, and there is a possibility of wrong wiring when changing the control circuit. Summary of the invention
[0004] The disclosed embodiments provide a control circuit and control method for a dual-speed fan, which can replace the fan without changing the control circuit. It only requires changing the wiring between the fan and the control circuit, thus avoiding the situation where the control circuit is connected incorrectly, saving time and effort.
[0005] To achieve the above objectives, the embodiments of the present disclosure adopt the following technical solutions:
[0006] On the one hand, a control circuit for a two-speed fan is provided, wherein the output end of the control circuit is used to couple a first two-speed fan or a second two-speed fan, wherein the first two-speed fan and the second two-speed fan are different, and the control circuit comprises: a first contactor, a second contactor, a third contactor, and a fourth contactor. Among them, the first end of the main contact of the first contactor is used to couple with a three-phase power supply, and the second end of the main contact of the first contactor is the first output end of the control circuit. The first end of the main contact of the second contactor is coupled with the first end of the main contact of the fourth contactor, and the second end of the main contact of the second contactor is coupled with the second end of the main contact of the first contactor. The first end of the main contact of the third contactor is short-circuited, and the second end of the main contact of the third contactor is coupled with the second end of the main contact of the first contactor. The second end of the main contact of the fourth contactor is coupled with the first end of the main contact of the first contactor, and the first end of the main contact of the fourth contactor is the second output end of the control circuit.
[0007] On the other hand, a control method for a two-speed fan is provided, which is applied to the control circuit of the two-speed fan described in any embodiment of the present disclosure, the method comprising: controlling the first contactor to be energized so that the first two-speed fan runs at a low speed; controlling the third contactor and the fourth contactor to be energized so that the first two-speed fan runs at a high speed. BRIEF DESCRIPTION OF THE DRAWINGS
[0008] In order to more clearly illustrate the technical solutions in the present disclosure, the following briefly introduces the drawings required to be used in some embodiments of the present disclosure. Obviously, the drawings described below are only drawings of some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can also be obtained based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams, and are not limitations on the actual size of the product involved in the embodiments of the present disclosure, the actual process of the method, the actual timing of the signal, etc.
[0009] Figure 1 is a circuit diagram of a control circuit of a first dual-speed fan in the related art;
[0010] Figure 2 is a schematic diagram of a connection method of windings of a first dual-speed fan in the related art;
[0011] Figure 3 is a circuit diagram of a control circuit of a second dual-speed fan in the related art;
[0012] Figure 4 A schematic diagram of a connection method of the windings of a second dual-speed fan in the related art;
[0013] Figure 5 A schematic diagram of another connection method of the windings of the second dual-speed fan in the related art;
[0014] Figure 6 A circuit diagram of a control circuit of a dual-speed fan provided in some embodiments of the present disclosure;
[0015] Figure 7 A schematic diagram of an application of a control circuit for a dual-speed fan provided in some embodiments of the present disclosure;
[0016] Figure 8 A schematic diagram of the application of another control circuit for a dual-speed fan provided in some embodiments of the present disclosure. DETAILED DESCRIPTION
[0017] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in some embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments provided by the present disclosure, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present disclosure.
[0018] Unless the context requires otherwise, throughout the specification and claims, the term "including" is to be interpreted as an open, inclusive meaning, that is, "including, but not limited to". In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiments", "examples" or "some examples" and the like are intended to indicate that specific features, structures, materials or characteristics associated with the embodiment or example are included in at least one embodiment or example of the present disclosure. The schematic representations of the above terms do not necessarily refer to the same embodiment or example. In addition, the specific features, structures, materials or characteristics described may be included in any one or more embodiments or examples in any appropriate manner.
[0019] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present disclosure, unless otherwise specified, "plurality" means two or more.
[0020] When describing some embodiments, the expressions "coupled" and "connected" and their derivatives may be used. For example, when describing some embodiments, the term "connected" may be used to indicate that two or more components are in direct physical or electrical contact with each other. For another example, when describing some embodiments, the term "coupled" may be used to indicate that two or more components are in direct physical or electrical contact. However, the term "coupled" or "communicatively coupled" may also refer to two or more components that are not in direct contact with each other, but still cooperate or interact with each other. The embodiments disclosed herein are not necessarily limited to the contents of this document.
[0021] “At least one of A, B, and C” has the same meaning as “at least one of A, B, or C” and both include the following combinations of A, B, and C: A only, B only, C only, the combination of A and B, the combination of A and C, the combination of B and C, and the combination of A, B, and C.
[0022] “A and / or B” includes the following three combinations: A only, B only, and a combination of A and B.
[0023] As used herein, the term "if" is optionally interpreted to mean "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrases "if it is determined that" or "if [a stated condition or event] is detected" are optionally interpreted to mean "upon determining that" or "in response to determining that" or "upon detecting [a stated condition or event]" or "in response to detecting [a stated condition or event]," depending on the context.
[0024] The use of "adapted to" or "configured to" herein is meant to be open and inclusive language that does not exclude devices adapted or configured to perform additional tasks or steps.
[0025] Additionally, the use of “based on” is meant to be open and inclusive, as a process, step, calculation, or other action “based on” one or more stated conditions or values may, in practice, be based on additional conditions or values beyond those stated.
[0026] As used herein, "about," "substantially," or "approximately" includes the stated value and an average value that is within an acceptable range of variation from the particular value as determined by one of ordinary skill in the art taking into account the measurements in question and the errors associated with the measurement of the particular quantity (i.e., the limitations of the measurement system).
[0027] A two-speed fan is essentially an asynchronous motor that changes its speed by changing the number of pole pairs of the motor stator winding. A two-speed fan can run at two fixed speeds, low or high, and the speed at high speed is roughly twice the speed at low speed. When a two-speed motor changes from low speed to high speed, there are usually two ways to connect the windings of the two-speed fan: one is from triangle to double star, and the other is from single star to triangle. Both changes in the connection of the windings can reduce the number of pole pairs generated by the motor by half, thereby doubling the speed of the motor.
[0028] The first two-speed fan M1 and the second two-speed fan M2 in some embodiments of the present disclosure are different. The difference between the two fans is that the winding of the first two-speed fan M1 is six coils, the winding of the second two-speed fan M2 is three coils, and the working principles of the first two-speed fan M1 and the second two-speed fan M2 are different.
[0029] The control circuit of the two-speed fan includes a contactor, and the contactor includes three groups of main contacts: 1L1-2T1, 3L2-4T2, and 5L3-6T3. In the related technical description of the present disclosure, an example is given in which the first end of the main contact of the contactor includes the main contacts: 1L1, 3L2, and 5L3; and the second end of the main contact of the contactor includes the main contacts: 2T1, 4T2, and 6T3.
[0030] Figure 1 FIG. 1 is a circuit diagram of a control circuit of a first dual-speed fan in a related art. Figure 1 As shown, the control circuit includes a first dual-speed fan M1, an air switch S, fuses F1 to F3, contactors KM1 to KM3, a terminal block TB1 and a three-phase power supply L1-L3.
[0031] The first two-speed fan M1 includes a first terminal and a second terminal, the first terminal includes U1, V1 and W1, and the second terminal includes U2, V2 and W2. When the first two-speed fan M1 runs at a low speed, the connection mode of the winding of the first two-speed fan M1 is a triangle. When the first two-speed fan M1 runs at a high speed, the connection mode of the winding of the first two-speed fan M1 is a double star. The first two-speed fan M1 can also be called a variable-speed two-speed fan.
[0032] One end of the fuse F1 to the fuse F3 is coupled to the three-phase power supply L1-L3 respectively through the air switch S, and the other end of the fuse F1 to the fuse F3 is coupled to the first end of the main contact of the contactor KM1 and the first end of the main contact of the contactor KM2. The fuse F1 to the fuse F3 are used to protect the control circuit.
[0033] The first ends 1L1, 3L2, 5L3 of the main contacts of the contactor KM1 are respectively used to couple with the three-phase power supplies L1, L2, L3. The second ends 2T1, 4T2, 6T3 of the main contacts of the contactor KM1 are respectively the first output ends O1, O2, O3 of the control circuit. The first output end of the control circuit is used to couple with the first terminals U1, V1 and W1 of the first two-speed fan M1.
[0034] The first ends 1L1, 3L2, 5L3 of the main contacts of the contactor KM2 are respectively coupled to the first ends 1L1, 3L2, 5L3 of the main contacts of the contactor KM1. The second ends 2T1, 4T2 and 6T3 of the main contacts of the contactor KM2 are respectively the second output ends O4, O5, O6 of the control circuit. The second output end of the control circuit is used to couple with the second terminals U2, V2 and W2 of the first two-speed fan M1.
[0035] The first terminals 1L1, 3L2, 5L3 of the main contacts of the contactor KM3 are short-circuited. The second terminals 2T1, 4T2, 6T3 of the main contacts of the contactor KM3 are coupled to the second terminals 6T3, 4T2, 2T1 of the main contacts of the contactor KM1, respectively.
[0036] Control circuit control loop ( Figure 1 (not shown in the figure), contactors KM1 to KM3 are controlled by different control signals respectively. For example, control signal 1 controls contactor KM1, control signal 2 controls contactor KM2, and control signal 3 controls contactor KM3.
[0037] In some embodiments, when the first dual-speed fan M1 runs at a low speed, the control signal 1 controls the contactor KM1 to be energized, and the first terminals U1, V1, and W1 of the first dual-speed fan M1 obtain three-phase power, such as Figure 2 As shown, when the first dual-speed fan M1 runs at a low speed, the connection mode of the windings of the first dual-speed fan M1 is a triangle.
[0038] In some embodiments, when the first two-speed fan M1 runs at high speed, the control signal 2 controls the contactor KM2 to be energized, and the control signal 3 controls the contactor KM3 to be energized. The second terminals U2, V2, and W2 of the first two-speed fan M1 obtain three-phase power. Since the first end of the main contact of the contactor KM3 is short-circuited, it is equivalent to short-circuiting the first terminals U1, V1, and W1 of the first two-speed fan M1. Figure 2 As shown, when the first dual-speed fan M1 runs at high speed, the connection mode of the winding is changed to double star.
[0039] Figure 3 FIG. 1 is a circuit diagram of a control circuit of a second dual-speed fan in a related art. Figure 3 As shown, the control circuit includes a second two-speed fan M2, an air switch S, fuses F1 to F3, contactors CMCF1 to CMCF3, a terminal block TB2 and a three-phase power supply L1-L3.
[0040] The second two-speed fan M2 includes a first terminal and a second terminal, the first terminal includes U1, V1 and W1, and the second terminal includes U2, V2 and W2. When the second two-speed fan M2 runs at a low speed, the connection mode of the winding of the second two-speed fan M2 is a single star; when the second two-speed fan M2 runs at a high speed, the connection mode of the winding of the second two-speed fan M2 is a triangle. The second two-speed fan M2 can also be called a star-delta two-speed fan.
[0041] One end of the fuse F1 to the fuse F3 is respectively coupled to the three-phase power supply L1-L3 through the air switch S, and the other end of the fuse F1 to the fuse F3 is respectively coupled to the first end of the main contact of the contactor CMCF1. The fuse F1 to the fuse F3 are used to protect the control circuit.
[0042] The first ends 1L1, 3L2, 5L3 of the main contacts of the contactor CMCF1 are respectively used to couple with the three-phase power supplies L1, L2, L3, and the second ends 2T1, 4T2, 6T3 of the main contacts of the contactor CMCF1 are the first output ends O1, O2, O3 of the control circuit. The first output end of the control circuit is used to couple with the first terminals U1, V1 and W1 of the second two-speed fan M2.
[0043] The first ends 1L1, 3L2, 5L3 of the main contacts of the contactor CMCF2 are respectively coupled to the second ends 4T2, 6T3, 2T1 of the main contacts of the contactor CMCF1. The second ends 2T1, 4T2, 6T3 of the main contacts of the contactor CMCF2 are respectively the second output ends O4, O5, O6 of the control circuit. The second output end of the control circuit is used to couple with the second terminals U2, V2 and W2 of the second dual-speed fan M2.
[0044] The first ends 1L1, 3L2, 5L3 of the main contacts of the contactor CMCF3 are short-circuited, and the second ends 2T1, 4T2, 6T3 of the main contacts of the contactor CMCF3 are coupled to the second ends 2T1, 4T2, 6T3 of the main contacts of the contactor CMCF2, respectively.
[0045] Control circuit control loop ( Figure 3 (not shown in the figure), contactors CMCF1 to CMCF3 are controlled by different control signals respectively. For example, control signal 4 controls contactor CMCF1, control signal 5 controls contactor CMCF2, and control signal 6 controls contactor CMCF3.
[0046] When the second two-speed fan M2 runs at low speed, control signal 4 controls contactor CMCF1 to be energized, and control signal 6 controls contactor CMCF3 to be energized. The first terminals U1, V1, and W1 of the second two-speed fan M2 obtain three-phase power. Since the first terminal of the main contact of contactor CMCF3 is short-circuited, the second terminals U2, V2, and W2 of the second two-speed fan M2 are short-circuited. Figure 4 As shown, when the second two-speed fan M2 runs at a low speed, the connection mode of the winding of the second two-speed fan M2 is a single star.
[0047] When the second dual-speed fan M2 runs at high speed, control signal 4 controls contactor CMCF1 to be attracted, and control signal 5 controls contactor CMCF2 to be attracted. Figure 5 As shown, the U1 end of the second two-speed fan M2 is connected to the W2 end, the U2 end is connected to the V1 end, the V2 end is connected to the W1 end, and the connection mode of the winding of the second two-speed fan M2 is a triangle.
[0048] Combination Figures 1 to 5 It can be seen that the first two-speed fan M1 is different from the second two-speed fan M2. When the two fans are running at low speed or high speed, the connection method of the fan winding is different, which makes the control circuit of the fan different. When the control circuit is fixed, if the fan needs to be replaced, the control circuit must also be changed. The switching operation is time-consuming and laborious, and there is a possibility of wrong wiring when changing the control circuit.
[0049] To this end, some embodiments of the present disclosure provide a control circuit for a dual-speed fan, such as Figure 6As shown, the control circuit includes: a first contactor KM1, a second contactor KM2, a third contactor KM3, and a fourth contactor KM4.
[0050] The following embodiments are exemplified by taking as an example that the first ends of the main contacts of the first contactor KM1, the second contactor KM2 and the third contactor KM3 include the main contacts 1L1, 3L2 and 5L3; and the second ends of the main contacts of the first contactor KM1, the second contactor KM2 and the third contactor KM3 include the main contacts 2T1, 4T2 and 6T3. Also, the first ends of the main contacts of the fourth contactor KM4 include the main contacts 2T1, 4T2 and 6T3, and the second ends of the main contacts of the fourth contactor KM4 include the main contacts 1L1, 3L2 and 5L3.
[0051] The output terminals O1-O6 of the control circuit are used to couple the first dual-speed fan M1 or the second dual-speed fan M2. The first output terminal of the control circuit includes O1-O3, and the second output terminal of the control circuit includes O4-O6.
[0052] The first ends 1L1, 3L2 and 5L3 of the main contacts of the first contactor KM1 are respectively used to couple with the three-phase power supplies L1, L2, L3, and the second ends 2T1, 4T2 and 6T3 of the main contacts of the first contactor KM1 are respectively the first output ends O1, O2, O3 of the control circuit.
[0053] The first terminals 1L1, 3L2, 5L3 of the main contacts of the second contactor KM2 are respectively coupled to the first terminals 4T2, 6T3, 2T1 of the main contacts of the fourth contactor KM4. The second terminals 2T1, 4T2 and 6T3 of the main contacts of the second contactor KM2 are respectively coupled to the second terminals 2T1, 4T2 and 6T3 of the main contacts of the first contactor KM1.
[0054] The first ends 1L1, 3L2, 5L3 of the main contacts of the third contactor KM3 are short-circuited, and the second ends 2T1, 4T2, and 6T3 of the main contacts of the third contactor KM3 are coupled to the second ends 6T3, 4T2, 2T1 of the main contacts of the first contactor KM1, respectively.
[0055] The second terminals 1L1, 3L2, 5L3 of the main contacts of the fourth contactor KM4 are respectively coupled to the first terminals 1L1, 3L2, 5L3 of the main contacts of the first contactor KM1. The first terminals 2T1, 4T2, 6T3 of the main contacts of the fourth contactor KM4 are respectively the second output terminals O4, O5, O6 of the control circuit.
[0056] Some embodiments of the present disclosure provide an application schematic diagram of a control circuit for a dual-speed fan, such as Figure 7As shown, the first output terminals O1-O3 of the control circuit are respectively used to couple the first terminals U1, V1, W1 of the first dual-speed fan M1 through the terminal block TB. The second output terminals O4-O6 of the control circuit are respectively used to couple the second terminals U2, V2, W2 of the first dual-speed fan M1 through the terminal block TB.
[0057] In some embodiments, when the first contactor KM1 is energized, the Figure 2 , the first output terminal O1-O3 of the control circuit is powered, that is, the first connection terminals U1, V1, and W1 of the first two-speed fan M1 are powered, and the first two-speed fan M1 runs at a low speed.
[0058] In some embodiments, when the third contactor KM3 and the fourth contactor KM4 are energized, the second output terminal O4-O6 of the control circuit is energized, that is, the second terminal U2, V2, and W2 of the first two-speed fan M1 obtain three-phase electricity. Since the first end of the main contact of the third contactor KM3 is short-circuited, it is equivalent to short-circuiting the first terminal U1, V1, and W1 of the first two-speed fan M1. The connection mode of the winding of the first two-speed fan M1 is changed to a double star, and the first two-speed fan M1 runs at high speed.
[0059] Some embodiments of the present disclosure provide another application schematic diagram of a control circuit for a dual-speed fan, such as Figure 8 As shown, the first output terminals O1-O3 of the control circuit are respectively used to couple the second terminals U2, V2, W2 of the second dual-speed fan M2 through the terminal block TB. The second output terminals O4-O6 of the control circuit are respectively used to couple the first terminals U1, V1, W1 of the second dual-speed fan M2 through the terminal block TB.
[0060] In some embodiments, when the third contactor KM3 and the fourth contactor KM4 are energized, the combination Figure 4 , the second output terminal O4-O6 of the control circuit is energized, that is, the first terminals U1, V1, and W1 of the second two-speed fan M2 are energized. Since the first end of the main contact of the third contactor KM3 is short-circuited, it is equivalent to short-circuiting the second terminals U2, V2, and W2 of the second two-speed fan M2. The connection mode of the winding of the second two-speed fan M2 is single star, and the second two-speed fan M2 runs at low speed.
[0061] In some embodiments, when the second contactor KM2 and the fourth contactor KM4 are energized, the combination Figure 5 , the first output terminal O1-O3 of the control circuit is powered, that is, the second connection terminals U2, V2, and W2 of the second two-speed fan M2 are powered, the U1 terminal of the second two-speed fan M2 is connected to the W2 terminal, the U2 terminal is connected to the V1 terminal, and the V2 terminal is connected to the W1 terminal. The connection method of the winding of the second two-speed fan M2 is a triangle. At this time, the second two-speed fan M2 runs at high speed.
[0062] Some embodiments of the present disclosure provide a control circuit for a two-speed fan. When the fan needs to be replaced, there is no need to change the control circuit. It is only necessary to change the wiring of the two-speed fan and the control circuit to avoid the situation where the control circuit is connected incorrectly, saving time and effort. In addition, the control circuit of the first two-speed fan M1 requires three contactors KM1-KM3, and the control circuit of the second two-speed fan M2 requires three contactors CMCF1-CMCF3. The two control circuits require a total of six contactors. The control circuit of the two-speed fan provided by some embodiments of the present disclosure only requires four contactors KM1-KM4, saving costs.
[0063] Some embodiments of the present disclosure provide a control method for a dual-speed fan, which is applied to a control circuit of a dual-speed fan as described in any of the above embodiments, and controls the operation of a first dual-speed fan M1, the method comprising:
[0064] The first contactor KM1 is controlled to be attracted so that the first dual-speed fan M1 runs at a low speed.
[0065] Exemplarily, the first contactor KM1 is controlled to be energized so that the connection mode of the windings of the first two-speed fan M1 is a triangle, and at this time, the first two-speed fan M1 runs at a low speed.
[0066] The third contactor KM3 and the fourth contactor KM4 are controlled to be attracted so that the first dual-speed fan M1 runs at high speed.
[0067] Exemplarily, the third contactor KM3 and the fourth contactor KM4 are controlled to be energized, so that the connection mode of the windings of the first two-speed fan M1 is double star, and at this time, the first two-speed fan M1 runs at high speed.
[0068] In some embodiments, when controlling the second dual-speed fan M2 to operate, the dual-speed fan control method further includes:
[0069] The third contactor KM3 and the fourth contactor KM4 are controlled to be attracted so that the second dual-speed fan M2 runs at a low speed.
[0070] Exemplarily, the third contactor KM3 and the fourth contactor KM4 are controlled to be attracted, so that the connection mode of the winding of the second two-speed fan M2 is a single star, and the second two-speed fan M2 runs at a low speed.
[0071] The second contactor KM2 and the fourth contactor KM4 are controlled to be attracted so that the second dual-speed fan M2 runs at high speed.
[0072] Exemplarily, the second contactor KM2 and the fourth contactor KM4 are controlled to be attracted, so that the connection mode of the windings of the second two-speed fan M2 is a triangle, and the second two-speed fan M2 runs at a high speed.
[0073] The above is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any changes or substitutions that can be thought of by any person skilled in the art within the technical scope disclosed in the present disclosure should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.
Claims
1. A control circuit for a dual-speed fan, characterized in that: The first output terminal of the control circuit is used to couple with the first terminal of the first two-speed fan, the second output terminal of the control circuit is used to couple with the second terminal of the first two-speed fan, the first output terminal of the control circuit is used to couple with the second terminal of the second two-speed fan, the second output terminal of the control circuit is used to couple with the first terminal of the second two-speed fan, the first two-speed fan and the second two-speed fan are different, the control circuit includes: a first contactor, a second contactor, a third contactor, and a fourth contactor; wherein, The first end of the main contact of the first contactor is used to couple with a three-phase power supply, and the second end of the main contact of the first contactor is the first output end of the control circuit; The first end of the main contact of the second contactor is coupled to the first end of the main contact of the fourth contactor, and the second end of the main contact of the second contactor is coupled to the second end of the main contact of the first contactor; A first end of the main contact of the third contactor is short-circuited, and a second end of the main contact of the third contactor is coupled to a second end of the main contact of the first contactor; The second end of the main contact of the fourth contactor is coupled to the first end of the main contact of the first contactor, and the first end of the main contact of the fourth contactor is the second output end of the control circuit.
2. The control circuit according to claim 1, characterized in that: The first connection terminals of the first dual-speed fan and the second dual-speed fan include U1, V1, and W1, and the second connection terminals of the first dual-speed fan and the second dual-speed fan include U2, V2, and W2.
3. The control circuit according to claim 2, characterized in that: When the first contactor is energized, the first dual-speed fan runs at a low speed; when the third contactor and the fourth contactor are energized, the first dual-speed fan runs at a high speed.
4. The control circuit according to any one of claims 1 to 3, characterized in that: When the first two-speed fan runs at a low speed, the connection mode of the windings of the first two-speed fan is a triangle, and when the first two-speed fan runs at a high speed, the connection mode of the windings of the first two-speed fan is a double star.
5. The control circuit according to claim 4, characterized in that: When the third contactor and the fourth contactor are energized, the second two-speed fan runs at a low speed; when the second contactor and the fourth contactor are energized, the second two-speed fan runs at a high speed.
6. The control circuit according to claim 5, characterized in that: When the second two-speed fan runs at a low speed, the connection mode of the windings of the second two-speed fan is a single star. When the second two-speed fan runs at a high speed, the connection mode of the windings of the second two-speed fan is a triangle.
7. A control method for a dual-speed fan, characterized in that: A control circuit for a two-speed fan according to any one of claims 1 to 6, the method comprising: Controlling the first contactor to be attracted so that the first dual-speed fan runs at a low speed; The third contactor and the fourth contactor are controlled to be attracted so that the first dual-speed fan runs at high speed.
8. The control method according to claim 7, characterized in that: The method further comprises: Controlling the third contactor and the fourth contactor to be attracted, so that the second dual-speed fan runs at a low speed; The second contactor and the fourth contactor are controlled to be attracted so that the second dual-speed fan runs at high speed.