A three-phase electrical parameter measuring device and a terminal measuring device

Abstract

The present invention provides a three-phase electrical parameter metering device, including three processors corresponding to three-phase input electricity, three electrical parameter sampling modules corresponding to three-phase input electricity, and a power supply module; the processors are connected via a serial bus, and each of the processors is electrically connected to one of the electrical parameter sampling modules, and the power supply module is electrically connected to the processor in parallel; each of the electrical parameter sampling modules includes a mutual inductor current sampling circuit, a line voltage sampling circuit, and a phase voltage sampling circuit; the mutual inductor of the mutual inductor current sampling circuit includes at least two skeletons with cavities inside, the skeletons are provided with spacing and connected by alloy sheets, each of the skeletons is provided with a winding, and the winding and the alloy sheet form a closed magnetic circuit. A three-phase electrical parameter metering device and a terminal metering device provided in an embodiment of the present invention can realize the miniaturization of the electric quantity metering device and occupy less space in the distribution box.

Description

Technical Field

[0001] The present invention relates to the technical field of electric quantity metering, and in particular to a three-phase electric parameter metering device and a terminal metering device. Background Art

[0002] With the development of modern industry, electricity consumption continues to increase, and related electrical appliances for electricity monitoring are also constantly upgraded. Electricity meters used to collect and monitor electrical parameters are widely used in SCADA systems and energy efficiency management systems. At present, the existing electricity meters installed at the end of the distribution box generally adopt a guide rail installation method, and transmit data through a wired connection method; for the measurement of electrical parameters, a voltage transformer is used to measure the voltage, and a current transformer or manganese copper resistor is used to collect current parameters. However, due to the structural design of the large-size power frequency transformer inside the meter and the complex AC / DC power supply circuit in the meter, the meter is large in size and occupies more space in the distribution box. Summary of the invention

[0003] The embodiment of the present invention provides a three-phase electrical parameter metering device and a terminal metering device. On the basis of meeting the requirements of electricity metering, the transformer structure is optimized to reduce the volume of the transformer, so that the internal structure of the electricity metering device is more compact, so as to realize the miniaturization of the electricity metering device, thereby occupying less space in the distribution box. The technical solution is as follows:

[0004] The embodiment of the present invention provides a three-phase electrical parameter metering device, comprising three processors corresponding to three-phase input electricity, three electrical parameter sampling modules corresponding to three-phase input electricity, and a power supply module;

[0005] The processors are connected via a serial bus, and each of the processors is electrically connected to one of the electrical parameter sampling modules, and the power supply module is electrically connected to the processors in parallel;

[0006] Each of the electrical parameter sampling modules includes a transformer current sampling circuit, a line voltage sampling circuit, and a phase voltage sampling circuit;

[0007] The mutual inductor of the mutual inductor current sampling circuit comprises at least two skeletons with cavities inside, the skeletons are spaced apart and connected by alloy sheets, each skeleton is provided with a winding, and the winding and the alloy sheets form a closed magnetic circuit.

[0008] Preferably, the number of the skeleton and the number of the alloy sheets are both two, and two ends of one of the skeletons are connected to two ends of the other skeleton via one of the alloy sheets, respectively, to form a ring-shaped mutual inductor.

[0009] Preferably, the three-phase electrical parameter metering device further comprises a shell, wherein the shell is provided with a through hole penetrating the three-phase electrical parameter metering device; the processor, the power supply module and the electrical parameter sampling module are all located in the shell.

[0010] Preferably, the three-phase electrical parameter metering device further comprises a conductor connector for supplying power to an external power source, wherein the conductor connector extends from inside the housing through the through hole to outside the housing.

[0011] Preferably, the housing further includes a circuit board, the circuit board is provided with a through hole penetrating through the surface of the circuit board and communicating with the through hole of the housing, and the circuit board is electrically connected to the conductor connector;

[0012] The processor, the power supply module and the electrical parameter sampling module are arranged on the circuit board, and the circuit board is provided with a connection terminal for connecting with the mutual inductor.

[0013] Preferably, the power supply module is a resistor-capacitor step-down power supply circuit, and the processors are low-power microprocessors.

[0014] Preferably, the line voltage sampling circuit and the phase voltage sampling circuit are both resistance voltage division sampling circuits.

[0015] Preferably, the three-phase electrical parameter metering device further includes a power failure detection circuit, the input end of the power failure detection circuit is connected to the power output end of the power module, and the output end of the power failure detection circuit is connected to the power input end of the main processor among the three processors.

[0016] Preferably, the three-phase electrical parameter metering device further comprises a wireless communication circuit, and the wireless communication circuit is connected to the communication end of the main processor.

[0017] The embodiment of the present invention provides a terminal metering device for three-phase electrical parameters, comprising: an air switch, an electric wire, and the metering device for three-phase electrical parameters as described above;

[0018] The conductor connector of the three-phase electrical parameter metering device is inserted into the wire insertion hole of the air switch to connect the three-phase electrical parameter metering device to the air switch;

[0019] The electric wire passes through the three-phase electric parameter metering device and is inserted into the wire insertion hole of the air switch.

[0020] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0021] The present invention provides a three-phase electrical parameter metering device, which is assembled from a processor, a power module and an electrical parameter sampling module, wherein a mutual inductance current sampling method is used to sample the input current, and relevant electrical parameters, including the effective value of the current, are measured, so as to achieve the effect of accurately and efficiently measuring the electrical parameters. In order to avoid the disadvantage that the volume of the mutual inductor of the traditional mutual inductor current sampling method is large, resulting in a large volume of the metering device, the mutual inductor of the three-phase electrical parameter metering device provided by the present invention, because the alloy sheet is connected to the skeleton, and the interior of the skeleton is a cavity, it plays the role of an air magnetic core, which is smaller than the traditional magnetic core, thereby reducing the overall volume of the mutual inductor, and the magnetic permeability in the mutual inductor is low, and the magnetic flux is not easy to reach the saturation point, so that its measurement range is larger than that of the traditional current mutual inductor; in addition, compared with the magnetic core, the alloy sheet not only occupies less space, but also helps to enhance the magnetic flux of the air in the cavity, thereby enhancing the output of the small current signal, improving the accuracy of the small current signal, and then improving the measurement accuracy.

[0022] The present invention provides a three-phase electrical parameter terminal metering device, which is assembled from an air switch, electric wires and the above-mentioned three-phase electrical parameter metering device. Since the three-phase electrical parameter metering device is directly installed on the wiring post of the air switch to draw power, the electric wires of the measured circuit pass through the metering device, thereby conveniently and quickly measuring and monitoring the electrical parameters. At the same time, since the metering device is directly installed on the air switch, it does not need to occupy the installation position in the distribution box, thereby saving the space of the distribution box. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a functional module schematic diagram of a three-phase electrical parameter metering device in an embodiment of the present invention;

[0024] Figure 2 is a structural diagram of a transformer of a three-phase electrical parameter measuring device in an embodiment of the present invention;

[0025] Figure 3 It is a flow chart of a power failure detection method of a three-phase electrical parameter metering device in an embodiment of the present invention;

[0026] Figure 4 is a structural diagram of a three-phase electrical parameter metering device in an embodiment of the present invention;

[0027] Figure 5 It is a schematic diagram of the structural disassembly of a three-phase electrical parameter metering device in an embodiment of the present invention;

[0028] Figure 6 It is a schematic diagram of an electric parameter metering method of a first processor of a three-phase electric parameter metering device in an embodiment of the present invention;

[0029] Figure 7It is a schematic diagram of an electric parameter metering method of a second processor of a three-phase electric parameter metering device in an embodiment of the present invention;

[0030] Figure 8 is a schematic diagram of an electrical parameter measurement method of a third processor of a three-phase electrical parameter measurement device in an embodiment of the present invention;

[0031] Among them, 100, mutual inductor; 101, frame; 102, alloy sheet; 103, winding; 200, housing; 201, through hole; 202, indicator light; 301, upper plate; 302, lower plate; 401, conductor plate; 402, copper insert. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] See also Figure 1 , which shows a three-phase electrical parameter metering device of an exemplary embodiment of the present invention, including three processors corresponding to three-phase input electricity, three electrical parameter sampling modules corresponding to three-phase input electricity, and a power supply module;

[0034] The processors are connected via a serial bus, and each of the processors is electrically connected to one of the electrical parameter sampling modules, and the power supply module is electrically connected to the processors in parallel;

[0035] Each of the electrical parameter sampling modules includes a transformer current sampling circuit, a line voltage sampling circuit, and a phase voltage sampling circuit;

[0036] The transformer 100 of the transformer current sampling circuit includes at least two skeletons 101 with cavities inside. The skeletons 101 are spaced apart and connected by alloy sheets 102. Each skeleton 101 is provided with a winding 103. The winding 103 and the alloy sheets 102 form a closed magnetic circuit.

[0037] The embodiment of the present invention provides a three-phase electrical parameter metering device, which is assembled from a processor, a power module and an electrical parameter sampling module, wherein a mutual inductance current sampling method is used to sample the input current, and relevant electrical parameters, including the effective value of the current, are measured, so as to achieve the effect of accurately and efficiently measuring the electrical parameters. In order to avoid the disadvantage that the volume of the mutual inductor of the traditional mutual inductor current sampling method is large, resulting in a large volume of the metering device, the mutual inductor of the three-phase electrical parameter metering device provided by the present invention, because the alloy sheet is connected to the skeleton, and the interior of the skeleton is a cavity, it plays the role of an air magnetic core, which is smaller than the traditional magnetic core, thereby reducing the overall volume of the mutual inductor, and the magnetic permeability in the mutual inductor is low, and the magnetic flux is not easy to reach the saturation point, so that its measurement range is larger than that of the traditional current mutual inductor; in addition, compared with the magnetic core, the alloy sheet not only occupies less space, but also helps to enhance the magnetic flux of the air in the cavity, thereby enhancing the output of the small current signal, improving the accuracy of the small current signal, and then improving the measurement accuracy.

[0038] See also Figure 2 , which shows a mutual inductor 100 of a three-phase electrical parameter metering device according to an exemplary embodiment of the present invention, wherein the skeleton 101 and the alloy sheet 102 are each provided in two, wherein two ends of one of the skeletons 101 are connected to two ends of the other skeleton 101 through one of the alloy sheets 102, respectively, to form a ring-shaped mutual inductor 100.

[0039] It can be understood that, due to the limited resources and data processing capabilities of a single-chip microprocessor, the electrical parameter collection and calculation are performed by using three MCUs to collect and calculate each phase voltage, line voltage and line current respectively. One MCU is the main processor MCU1, and the other two are slave processors MCU2 and MCU3. MCU1 reads the collection and calculation results from the slave processors MCU2 and MCU3 through serial bus communication, and communicates with the gateway wirelessly to upload data.

[0040] When measuring electrical parameters, the electric wire passes through the mutual inductor 100 inside the three-phase electrical parameter metering device, so that the mutual inductor 100 generates an induced current, so that the electrical parameter sampling module collects relevant parameters of the induced current, and the electrical parameter sampling module transmits the data obtained by collecting the induced current to the processor for processing, thereby realizing electrical parameter measurement.

[0041] The power supply module includes a rectifier circuit, a voltage stabilizing circuit and a DC step-down circuit;

[0042] The input end of the voltage stabilizing circuit is connected to the output end of the rectifier circuit, the output end of the voltage stabilizing circuit is connected to the input end of the DC step-down circuit, and the output end of the DC step-down circuit is connected to the power input end of the processor.

[0043] In order to further reduce the volume, the power module is a power circuit using a resistor-capacitor voltage reduction method, and the processor is a low-power microprocessor; preferably, the processor is TI's msp430i2041 low-power microprocessor (MCU).

[0044] It is understandable that in order to reduce the size of the power module, a RC step-down method is adopted. This power solution can only provide a small current supply. Therefore, a low-power design is performed as a whole. TI's msp430i2041 low-power microprocessor (MCU) is selected as the main device for data acquisition and calculation. It has built-in operational amplifiers and 4-channel 24-bit synchronous AD acquisition circuits to meet the collection and calculation of electrical parameters.

[0045] In this embodiment, the AC mains 230V input is used to reduce the voltage through resistors and capacitors, and then rectified to obtain DC power, which is then passed through a voltage stabilizer to obtain a stable voltage of 47V. The 47V voltage is then converted into a 3.3V supply voltage for the system through a DCDC power supply.

[0046] In order to further reduce the volume, the line voltage sampling circuit and the phase voltage sampling circuit are both resistor voltage division sampling circuits.

[0047] It is understandable that in order to reduce the size of the electrical parameter sampling module, a resistor voltage divider is used for voltage measurement, and the voltage obtained by the voltage divider is collected through the AD inside the MCU.

[0048] In this embodiment, the electrical parameter sampling module includes a current sampling circuit of a transformer 100 and a resistor voltage-dividing sampling circuit; the input end of the current sampling circuit of the transformer 100 is connected to the current source, and the output end thereof is connected to the current acquisition signal end of the processor; the input end of the resistor voltage-dividing sampling circuit is connected to the voltage source, and the output end thereof is connected to the voltage acquisition signal end of the processor.

[0049] The three-phase electrical parameter metering device also includes a power failure detection circuit, the input end of the power failure detection circuit is connected to the power output end of the power module, and the output end of the power failure detection circuit is connected to the power input end of the main processor among the three processors.

[0050] See also Figure 3 In terms of storage, due to the use of MCU's internal memory, the number of erase times is limited. In order to avoid frequent data writing, the electricity value is saved at the moment of power failure. Therefore, a power failure detection circuit is added, and the resistor voltage division principle is used to detect the voltage after the front-end 47V voltage regulator. Under normal circumstances, the voltage fluctuation of 47V will not be lower than 46V. Therefore, when the divided voltage value is lower than 40V, the MCU interrupt is triggered to save data, which is beneficial to protect the data of the electrical parameter meter and avoid accidental data loss.

[0051] The three-phase electrical parameter metering device further includes a wireless communication circuit, and the wireless communication circuit is connected to the communication end of the main processor.

[0052] It can be understood that the metering device of the three-phase electrical parameters is centrally installed in the distribution box. In order to avoid the inconvenience of wiring the voltage, current and communication bus, wireless communication is adopted, without the need for additional wiring, avoiding the installation of a large number of wires in the distribution box, thereby further saving space in the distribution box.

[0053] See also Figure 4 , which shows a three-phase electrical parameter metering device of an exemplary embodiment of the present invention, further comprising a housing 200, wherein the housing 200 is provided with a through hole 201 penetrating the three-phase electrical parameter metering device; the processor, the power module and the electrical parameter sampling module are built in the housing 200;

[0054] Preferably, an indicator light 202 is provided on the housing 200, and the indicator light 202 is electrically connected to the processor.

[0055] Preferably, the three-phase electrical parameter metering device also includes a conductor connector for connecting to an external power supply, and the conductor connector extends from the shell 200 through the through hole 201 to the outside of the shell 200; preferably, the conductor connector is a copper plug 402, and the three-phase electrical parameter metering device is electrically connected to the external power supply through the copper plug 402.

[0056] The through hole 201 includes a first through hole 201 and a second through hole 201;

[0057] The housing 200 can be separated into a first housing 200 and a second housing 200;

[0058] When measuring electrical parameters, one electric wire passes through the first through hole 201 and penetrates the three-phase electrical parameter metering device, and another electric wire passes through the second through hole 201 and penetrates the three-phase electrical parameter metering device; the copper plug 402 contacts the electric wire passing through the three-phase electrical parameter metering device and is connected together through the wiring terminals on the matching air switch.

[0059] Preferably, the three-phase electrical parameter metering device includes a circuit board for realizing the electrical parameter metering function, the circuit board is provided with a through hole penetrating the circuit board surface and communicating with the through hole 201 of the housing 200, and the circuit board is electrically connected to the conductor connector (preferably a copper plug);

[0060] The processor, the power module and the electrical parameter sampling module are arranged on the circuit board, and the circuit board is provided with a connection terminal for connecting with the mutual inductor 100 .

[0061] It is understandable that when the wire enters the interior of the housing through one of the through holes, the wire passes through the annular mutual inductor, and at the same time the wire passes through the through hole of the circuit board and passes out of the housing through another through hole of the housing.

[0062] See also Figure 5 , which shows a three-phase electrical parameter metering device according to an exemplary embodiment of the present invention, wherein the three-phase electrical parameter metering device includes two circuit boards, the two circuit boards are an upper plate 301 and a lower plate 302, both of which are provided with perforations penetrating the circuit board surfaces and communicating with the through hole 201 of the housing 200, and the upper plate 301 and the lower plate 302 are electrically connected;

[0063] Preferably, the upper plate 301 is connected to the lower plate 302 by a pin header connection method;

[0064] The upper plate 301 is provided with a connection terminal for connecting to the mutual inductor 100, and the processor, the power supply module and the electrical parameter sampling module are arranged on the lower plate 302;

[0065] The mutual inductor 100 is located between the upper plate 301 and the lower plate 302 , and the annular through hole 201 of the mutual inductor 100 is communicated with the through holes of the upper plate 301 and the lower plate 302 .

[0066] The lower plate 302 is connected to the conductor connector to obtain power and can measure voltage at the same time.

[0067] Preferably, the connection end is a pad, and the mutual inductor 100 is welded to the pad through a conductor to achieve electrical connection.

[0068] Preferably, the housing 200 further includes a conductor plate 401, the conductor plate 401 is provided with a through hole for the power line to pass through, and the conductor plate 401 is electrically connected to the power supply outside the three-phase electrical parameter metering device through the copper plug 402;

[0069] The conductor plate 401 is provided with a contact spring and is electrically connected to the lower plate 302 via the contact spring.

[0070] Preferably, the conductor plate 401 is a copper plate.

[0071] When installing the wires, one of the wires passes through the through hole 201 of the shell 200, the through hole of the upper plate 301, the mutual inductor 100, the through hole of the lower plate 302, and the through hole 201 of the shell 200 one by one, thereby passing through the three-phase electrical parameter metering device; the other wire passes through the through hole 201 of the shell 200, the through hole of the conductor plate 401, and the through hole 201 of the shell 200 one by one.

[0072] An exemplary embodiment of the present invention provides a terminal metering device for three-phase electrical parameters, comprising: an air switch, an electric wire, and the metering device for three-phase electrical parameters as described above;

[0073] The copper plug 402 of the three-phase electrical parameter metering device is inserted into the plug hole of the air switch to connect the three-phase electrical parameter metering device to the air switch, and the housing of the three-phase electrical parameter metering device is fitted with one end of the plug hole;

[0074] The electric wire passes through the three-phase electric parameter metering device from the through hole on the shell of the three-phase electric parameter metering device and is inserted into the wire insertion hole of the air switch.

[0075] An exemplary embodiment of the present invention provides a method for installing a terminal metering device for three-phase electrical parameters, wherein the above-mentioned metering device for three-phase electrical parameters is installed on an air switch, and the steps include:

[0076] Insert the copper plug 402 of the three-phase electrical parameter metering device into the wire plug hole of the air switch;

[0077] Pass the electric wire through the through hole 201 of the three-phase electric parameter metering device and insert it into the wire insertion hole;

[0078] Tighten the screws of the air switch to fix the wires and the copper insert 402 in the wire insertion hole.

[0079] The present invention provides a three-phase electrical parameter terminal metering device, which is assembled from an air switch, electric wires and the above-mentioned three-phase electrical parameter metering device. Since the three-phase electrical parameter metering device is directly installed on the wiring post of the air switch to draw power, the electric wires of the measured circuit pass through the metering device, thereby conveniently and quickly measuring and monitoring the electrical parameters. At the same time, since the metering device is directly installed on the air switch, it does not need to occupy the installation position in the distribution box, thereby saving the space of the distribution box.

[0080] See also Figure 6-8 , which shows an electrical parameter metering method of a three-phase electrical parameter metering device according to an exemplary embodiment of the present invention, and uses the above-mentioned three-phase electrical parameter metering device to measure electrical parameters, and the specific steps are as follows:

[0081] The electric parameter acquisition module is used to sample the current passing through the transformer 100 and the input voltage at the same time;

[0082] The sampled values ​​are transmitted to the processor for measuring the electrical parameters;

[0083] The main processor reads the electrical parameters of the other two processors;

[0084] Output electrical parameter measurement value.

[0085] The electrical parameter measurement values ​​include voltage effective value, current effective value, active power, reactive power, electricity value, etc.

[0086] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A three-phase electrical parameter measuring device, It is characterized in that It includes three processors corresponding to three-phase input electricity, three electrical parameter sampling modules corresponding to three-phase input electricity, and a power supply module; The processors are connected via a serial bus, and each of the processors is electrically connected to one of the electrical parameter sampling modules, and the power supply module is electrically connected to the processors in parallel; Each of the electrical parameter sampling modules includes a transformer current sampling circuit, a line voltage sampling circuit, and a phase voltage sampling circuit; The mutual inductor of the mutual inductor current sampling circuit comprises at least two skeletons with cavities inside, the skeletons are spaced apart and connected by alloy sheets, each skeleton is provided with a winding, and the winding and the alloy sheet form a closed magnetic circuit; The three-phase electrical parameter metering device comprises two circuit boards, the two circuit boards are an upper plate (301) and a lower plate (302) each having a perforation penetrating through the circuit board surface and communicating with a through hole (201) of a housing (200), the upper plate (301) and the lower plate (302) are electrically connected, the upper plate (301) is provided with a connection terminal for connecting to a mutual inductor (100), the processor, the power supply module and the electrical parameter sampling module are arranged on the lower plate (3 02), the mutual inductor (100) is located between the upper plate (301) and the lower plate (302), and the annular through hole of the mutual inductor (100) is connected to the through holes of the upper plate (301) and the lower plate (302), the lower plate (302) is connected to the conductor connector to obtain power, and the voltage can be measured at the same time, the housing (200) also includes a conductor plate (401), the conductor plate (401) is provided with a through hole for the power line to pass through, the conductor plate (401) is connected to the copper plug (401) 2) electrically connected to an external power source of the three-phase electrical parameter metering device, the conductor plate (401) is provided with a contact spring and is electrically connected to the lower plate (302) through the contact spring, and is used for a conductor connector connected to an external power source, the conductor connector extends from the inside of the housing (200) through the through hole (201) to the outside of the housing (200), the through hole (201) includes a first through hole and a second through hole, the housing (200) can be split into a first housing and a second housing, an electric wire passes through the three-phase electrical parameter metering device through the first through hole, and another electric wire passes through the three-phase electrical parameter metering device through the second through hole; the copper plug (402) contacts the electric wire passing through the three-phase electrical parameter metering device and is connected together through the wiring terminal on the matching air switch, the housing (200) is provided with a through hole (201) passing through the three-phase electrical parameter metering device, and the processor, the power module and the electrical parameter sampling module are built into the housing (200).

2. The three-phase electrical parameter measuring device according to claim 1, It is characterized in that The skeleton and the alloy sheet are both provided in two numbers, and two ends of one skeleton are connected to two ends of another skeleton through one alloy sheet respectively, so as to form a ring-shaped mutual inductor.

3. The three-phase electrical parameter measuring device according to claim 1, It is characterized in that The power supply module is a resistor-capacitor step-down power supply circuit, and the processor is a low-power microprocessor.

4. The three-phase electrical parameter measuring device according to claim 1, It is characterized in that The line voltage sampling circuit and the phase voltage sampling circuit are both resistance voltage division sampling circuits.

5. The three-phase electrical parameter measuring device according to claim 1, It is characterized in that It also includes a power failure detection circuit, the input end of the power failure detection circuit is connected to the power output end of the power module, and the output end of the power failure detection circuit is connected to the power input end of the main processor among the three processors.

6. The three-phase electrical parameter measuring device according to claim 1, It is characterized in that It also includes a wireless communication circuit, which is connected to the communication terminal of the main processor.

7. A terminal metering device for three-phase electrical parameters, It is characterized in that include: An air switch, an electric wire, and a three-phase electric parameter measuring device as claimed in any one of claims 1 to 6; The conductor connector of the three-phase electrical parameter metering device is inserted into the wire insertion hole of the air switch to connect the three-phase electrical parameter metering device to the air switch; The electric wire passes through the three-phase electric parameter metering device and is inserted into the wire insertion hole of the air switch.

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