A direct current universal polarity measuring instrument

Abstract

The application discloses a direct-current universal polarity measuring instrument, relates to the technical field of absorption tower flue inlet flushing, and comprises a measuring unit, which comprises an instrument box, a direct-current meter, a shunt, a resistor, four groups of wiring columns, a knob and a battery; further comprises a storage unit, which comprises an isolation plate, two groups of trigger assemblies, buckles, a jacking assembly, a connecting column and a fixing piece. The application has the beneficial effect of completely separating the wiring column from the line in the non-use state, effectively avoiding the risk of line short circuit, and quickly recycling the wiring column in the interior of the instrument box, preventing dust from falling on the inner side of the wiring column and affecting normal use. In addition, the application avoids damage that may be caused by the traditional frequent plugging and unplugging of the wiring column, and can achieve the effects of quick disengagement and adaptation to multiple models.

Description

Technical Field

[0001] This invention relates to the field of polarity measurement technology, and in particular to a DC universal polarity measuring instrument. Background Technology

[0002] In the final inspection and metering phase of 10kV and below power distribution projects, power distribution personnel often face a tedious task: performing polarity tests and wiring checks on equipment such as generators, motors, transformers, and instrument transformers. This work not only requires operating numerous cumbersome pieces of equipment and instruments, but also becomes even more complex when dealing with generators and motors whose nameplates are unclear or missing, making it even more challenging to determine their pole pair count and speed. Traditional methods rely on various tools and human resources, including using tachometers to measure rotational speed, verifying stator slot counts and coil pitch, etc. These tasks are not only time-consuming and labor-intensive, but also increase safety risks to personnel and equipment during the use of numerous tools. Therefore, a convenient polarity measuring instrument is needed.

[0003] Furthermore, existing measuring instruments often lack necessary protective features, making external terminals susceptible to damage from external vibrations. Additionally, dust can easily accumulate on the inside of the terminals when they are not in use for extended periods, affecting their normal operation and measurement accuracy. These problems, to some extent, increase the burden and inconvenience of power distribution personnel's daily work. Summary of the Invention

[0004] In view of the problems existing in the above or prior art, the present invention is proposed.

[0005] Therefore, the purpose of this invention is to provide a DC universal polarity measuring instrument that can solve the problem of the lack of a convenient polarity measuring tool and the problem of existing measuring instruments lacking protective functions.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a DC universal polarity measuring instrument, which includes a measuring unit, including an instrument box, a DC meter disposed inside the instrument box, a shunt disposed behind the DC meter, a resistor disposed on one side of the shunt, four sets of terminals disposed on the side of the instrument box, a knob disposed on one side of the resistor, and a battery disposed on one side of the knob;

[0007] It also includes a storage unit disposed around the periphery of the terminal block:

[0008] The storage unit can fold and store the terminal block.

[0009] As a preferred embodiment of the DC universal polarity measuring instrument of the present invention, the storage unit includes an isolation plate disposed in the inner interlayer of the instrument box, two sets of trigger components disposed above the isolation plate, a buckle disposed on one side of each set of trigger components, a lifting component disposed on one side of the trigger components, a connecting post disposed on one side of the lifting component, and a fixing member disposed at the front end of the connecting post.

[0010] In a preferred embodiment of the DC universal polarity measuring instrument of the present invention, the triggering component includes a guide groove fixedly disposed on the isolation plate, a large spring disposed inside the guide groove, and a sliding rod disposed at the front end of the large spring.

[0011] In a preferred embodiment of the DC universal polarity measuring instrument of the present invention, the sliding rod includes a pull rod disposed at the front end of the large spring, a latch disposed at the front end of the pull rod, and a sliding button disposed at the top end of the pull rod;

[0012] The buckle includes a claw that engages with the buckle lug, and a release rod located at the front end of the claw.

[0013] In a preferred embodiment of the DC universal polarity measuring instrument of the present invention, the lifting assembly includes a protrusion fixedly disposed on the side wall of the pull rod and a connecting member disposed inside the protrusion.

[0014] In a preferred embodiment of the DC universal polarity measuring instrument of the present invention, the protrusion includes a snap-fit ​​block fixedly connected to the pull rod, and a step block disposed on one side of the snap-fit ​​block;

[0015] The step block has a sliding groove inside, and one side of the step block is set as a first inclined surface.

[0016] In a preferred embodiment of the DC universal polarity measuring instrument of the present invention, the connecting member includes a small spring fixed to one side of the slide groove and a connecting block disposed on one side of the small spring.

[0017] As a preferred embodiment of the DC universal polarity measuring instrument of the present invention, the connecting column includes an outer copper column, a limiting block disposed inside the outer copper column, and a sliding sleeve disposed above the outer copper column.

[0018] The limiting block includes an L-shaped groove disposed on its inner side;

[0019] The sliding sleeve includes extension rods disposed on both sides thereof.

[0020] As a preferred embodiment of the DC universal polarity measuring instrument of the present invention, the fixing member includes an L-shaped block disposed on one side of the first inclined surface, and a limiting frame slidably disposed on one side of the L-shaped block;

[0021] The L-shaped block includes a second inclined surface disposed at its bottom.

[0022] As a preferred embodiment of the DC universal polarity measuring instrument of the present invention, the terminal block includes a sliding seat disposed in the L-shaped groove, a copper rod disposed above the sliding seat, and a petal-shaped post disposed above the copper rod.

[0023] A raised ring is provided on the inner side of the petal-shaped column;

[0024] The sliding sleeve is slidably fitted onto the outside of the petal-shaped column;

[0025] One side of the sliding seat is fixedly connected to the connecting block.

[0026] The beneficial effects of this invention are as follows: With its measuring and storage units, this device achieves complete separation of the terminals and wiring when not in use, effectively avoiding the risk of short circuits. It also allows for quick retraction of the terminals into the instrument box, preventing dust accumulation on the inside of the terminals and ensuring their normal operation. Furthermore, it avoids the damage that can result from frequent plugging and unplugging of terminals, and provides rapid disconnection and compatibility with various models. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is the schematic diagram of the DC universal polarity measuring instrument of the present invention.

[0029] Figure 2 This is a schematic diagram of the overall structure of the DC universal polarity measuring instrument of the present invention.

[0030] Figure 3 This is an exploded view of the internal structure of the DC universal polarity measuring instrument of the present invention.

[0031] Figure 4 This is a schematic diagram of a partial structural fracture of the DC universal polarity measuring instrument of the present invention.

[0032] Figure 5 for Figure 3 A partial structural diagram of the storage unit.

[0033] Figure 6 This is a schematic diagram of the triggering component and lifting component of the present invention.

[0034] Figure 7 This is a schematic diagram of the connecting column structure of the present invention. Detailed Implementation

[0035] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0036] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0037] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it a single embodiment or an embodiment selectively excluded from other embodiments.

[0038] Example 1, referring to Figures 1-3 This is the first embodiment of the present invention. This embodiment provides a DC universal polarity measuring instrument, which includes a measuring unit 100, including an instrument box 101, a DC meter 102 disposed inside the instrument box 101, a shunt 103 disposed behind the DC meter 102, a resistor 104 disposed on one side of the shunt 103, four sets of terminals 105 disposed on the side of the instrument box 101, a knob 106 disposed on one side of the resistor 104, and a battery 107 disposed on one side of the knob 106.

[0039] It also includes a storage unit 200 located around the terminal 105:

[0040] The storage unit 200 can fold and store the terminal 105.

[0041] It should be noted that the DC meter 101 used in this device is a DC 1000UA positive and negative meter, which is quite sensitive to induced current. Secondly, knob 106 is a 2-layer, 5-position selector switch, and battery 107 is selected as four 1.5V-6V 1500MA 1.5V lithium batteries. This device aims to reduce the burden on workers by eliminating the need for bulky tools and equipment, improve work efficiency, and reduce operational safety risks. It scientifically and rationally combines the DC meter 101, shunt, resistor, connecting wires, terminals, 4-position battery box, 2-layer, 5-position selector switch, 107 1.5V-6V 1500MA DC lithium batteries, 4-position charging box, battery voltage display, quick-measurement connecting wires, buttons, etc., to create a universal DC polarity measuring instrument.

[0042] By selecting the DC voltage of the conversion switch based on the coil impedance, the staff can easily, efficiently and quickly determine the polarity of the electromagnetic induction coil and the number of cuts using the principle of residual magnetic induction. After connecting a DC universal polarity measuring instrument to the start and end of any phase coil of the generator or motor and rotating the generator or motor rotor once, the number of pole pairs and the speed can be easily measured, and the number of poles of the motor can be determined.

[0043] like Figure 1 The principle shown is as follows: The method of using the current transformer polarity tester is as follows: Quickly select the appropriate DC voltage setting using the selector switch based on the coil impedance. The voltage display is clear. The polarity tester uses the DC method to determine the polarity of the primary and secondary wiring of the current transformer. Connect the primary terminals L1 and L2 of the tester to P1 and P2 of the primary winding of the current transformer, respectively. Connect the secondary terminals of the polarity tester to S1 and S2 of the current transformer, respectively, to S1 and S2 of the secondary wiring led to the lower end of the junction box. After forming a circuit, control the current / voltage flow (on / off) using the measurement button. Determine the polarity of the current transformer by observing the direction of the mechanical pointer deflection on the DC display meter.

[0044] Example 2, refer to Figures 1 to 7 This is the second embodiment of the present invention, which differs from the first embodiment in that it further includes a measuring unit 100, including an instrument box 101, a DC meter 102 disposed inside the instrument box 101, a shunt 103 disposed behind the DC meter 102, a resistor 104 disposed on one side of the shunt 103, four sets of terminals 105 disposed on the side of the instrument box 101, a knob 106 disposed on one side of the resistor 104, and a battery 107 disposed on one side of the knob 106.

[0045] It also includes a storage unit 200 located around the terminal 105:

[0046] The storage unit 200 can fold and store the terminal 105.

[0047] Furthermore, the storage unit 200 includes an isolation plate 201 disposed in the inner interlayer of the instrument box 101, two sets of trigger components 202 disposed above the isolation plate 201, a buckle 203 disposed on one side of each set of trigger components 202, a lifting component 204 disposed on one side of the trigger component 202, a connecting post 205 disposed on one side of the lifting component 204, and a fastener 206 disposed at the front end of the connecting post 205.

[0048] Furthermore, the triggering component 202 includes a guide groove 202a fixedly disposed on the isolation plate 201, a large spring 202b disposed inside the guide groove 202a, and a sliding rod 202c disposed at the front end of the large spring 202b.

[0049] Furthermore, the sliding rod 202c includes a pull rod 202c-1 disposed at the front end of the large spring 202b, a latch 202c-2 disposed at the front end of the pull rod 202c-1, and a sliding button 202c-3 disposed at the top end of the pull rod 202c-1;

[0050] The latch 203 includes a latch 203a that is movably engaged with the latch ear 202c-2, and a release lever 203b located at the front end of the latch 203a.

[0051] Furthermore, the lifting assembly 204 includes a protrusion 204a fixedly disposed on the side wall of the tie rod 202c-1, and a connector 204b disposed inside the protrusion 204a.

[0052] Furthermore, the protrusion 204a includes a snap-fit ​​block 204a-1 fixedly connected to the pull rod 202c-1, and a step block 204a-2 disposed on one side of the snap-fit ​​block 204a-1;

[0053] The step block 204a-2 has a sliding groove 204a-21 inside, and one side of the step block 204a-2 is set as a first inclined surface 204a-22.

[0054] Furthermore, the connector 204b includes a small spring 204b-1 fixed to one side of the slide groove 204a-21, and a connecting block 204b-2 disposed on one side of the small spring 204b-1.

[0055] Furthermore, the connecting column 205 includes an outer copper column 205a, a limiting block 205b disposed inside the outer copper column 205a, and a sliding sleeve 205c disposed above the outer copper column 205a.

[0056] The limiting block 205b includes an L-shaped groove 205b-1 disposed on its inner side;

[0057] The sliding sleeve 205c includes extension rods 205c-1 disposed on both sides thereof.

[0058] Furthermore, the fastener 206 includes an L-shaped block 206a disposed on one side of the first inclined surface 204a-22.

[0059] And a limiting frame 206b that is slidably disposed on one side of the L-shaped block 206a;

[0060] L-shaped block 206a includes a second inclined surface 206a-1 disposed at its bottom.

[0061] Furthermore, the terminal block 105 includes a sliding seat 105a disposed in the L-shaped groove 205b-1, a copper rod 105b disposed above the sliding seat 105a, and a petal-shaped post 105c disposed above the copper rod 105b.

[0062] A raised ring 105c-1 is provided on the inner side of the petal-shaped column 105c;

[0063] The sliding sleeve 205c is slidably connected to the outside of the petal-shaped column 105c.

[0064] The sliding seat 105a is fixedly connected to the connecting block 204b-2 on one side.

[0065] It should be noted that the storage unit 200 can fold and store the four sets of assembled terminals 105 to avoid the influence of the external environment on the terminals, so as to reduce the impact of dust accumulation and reduce the damage to the terminals 105 during the movement of the terminals 105.

[0066] Better, such as Figure 3 As shown, suspension ribs are fixedly installed around the inner perimeter of the instrument box 101. An isolation plate 201 is snapped onto the suspension ribs, and a storage unit 200 is easily installed on the isolation plate 201. Terminals 105 are respectively arranged on the perimeter of the instrument box 101, in pairs. A trigger assembly 202 is fixedly installed inside each group of terminals 105, which can drive the terminals 105 to rotate and fold. For example... Figure 4 As shown, the trigger assembly 202 consists of a guide groove 202a fixedly connected to the isolation plate 201, a large spring 202b disposed inside the guide groove 202a, and a sliding rod 202c at the front end of the large spring 202b. The guide groove 202a can be an integral structure with the isolation plate 201 and can be made of plastic with good mechanical strength and insulation properties. A rectangular large spring 202b is fixedly connected to the bottom of the guide groove 202a. Similarly, a sliding rod 202c is fixedly connected to the front end of the large spring 202b. Two sets of snap-fit ​​holes are formed on the sliding rod 202c according to the position relationship of the terminal 105. These snap-fit ​​holes provide a motion connection for the lifting assembly 204 to rotate.

[0067] Better, such as Figure 5As shown, a sliding button 202c-3 extends from the upper part of the sliding rod 202c. This sliding button 202c-3 can directly pull the large spring 202b at the rear end of the sliding rod 202c. Furthermore, to facilitate the movement of the sliding button 202c-3, a slot is provided at the corresponding position of the guide groove 202a. Two sets of latches 202c-2 extend to both sides from the front end of the sliding rod 202c. A set of latches 203 are movably engaged on the side wall of the instrument panel 101 in front of the latches 202c-2. The latches 203 are made of a claw 203a that matches the latches 202c-2. The claw 203a is an elastic plastic part that can be engaged precisely within the claw 203a during the forward movement of the latches 202c-2. A release lever 203b is fixedly connected to the rear of the pawl 203a. The release lever 203b consists of three sets of levers, two of which are fixedly connected to the instrument box 101, and the middle lever is slidably connected to the instrument box 101. When the release lever 203b is pushed backward, the pawl 203a extends outward, releasing the restriction on the latch 202c-2 and allowing the sliding lever 202c to retract as a whole.

[0068] Better, such as Figure 6 As shown, two sets of snap-fit ​​holes on the sliding rod 202c are connected to the lifting assembly 204. The lifting assembly 204 consists of a protrusion 204a and a connecting piece inside the protrusion 204a. The protrusion 204a is made of plastic and consists of a snap-fit ​​block 204a-1 that snaps into the snap-fit ​​holes on the sliding rod 202c, and a step block 204a-2 on one side of the snap-fit ​​block 204a-1. A sliding groove 204a-21 is formed on the inner side of the step block 204a-2. A set of small springs 204b-1 is fixedly connected to the front end of the sliding groove 204a-21, and a set of connecting blocks 204b-2 is fixedly connected to the rear end of the small springs 204b-1. The connecting piece 204b ensures that the sliding rod 202c does not interfere with the movement of the connecting post 205 during continuous retraction.

[0069] Better, such as Figure 6 As shown, the terminal 105 consists of a sliding seat 105a at its bottom, a copper rod 105b above the sliding seat 105a, and a petal-shaped post 105c above the copper rod 105b. The sliding seat 105a, copper rod 105b, and petal-shaped post 105c are all made of copper and are conductive. The sliding seat 105a has two sets of extension rods at both ends. The connecting post 205 consists of an outer copper post 205a, a limiting block 205b, and a sliding sleeve 205c fitted onto the outside of the petal-shaped post 105c. The outer copper post 205a is made of copper and is conductive, while the limiting block 205b is made of insulating material, allowing the sliding seat 105a to disconnect from the circuit during movement. The limiting block 205b engages in a receiving groove inside the outer copper post 205a. One side extension rod of the sliding seat 105a is hinged to the connecting block 204b-2.

[0070] Better, such as Figure 7 As shown, an L-shaped groove 205b-1 is formed in the limiting block 205b. The L-shaped groove 205b-1 has a horizontal groove at the top and a vertical groove extending forward. When the connecting block 204b-2 moves to the rear end, it pushes the sliding seat 105a to move along the L-shaped groove 205b-1, causing the terminal 105, which was originally in a horizontal state, to rotate counterclockwise to a vertical state. This causes one side of the sliding seat 105a to move from a state of not contacting the outer copper post 205a to a state of contacting the outer copper post 205a, thereby achieving the closure / opening of the terminal 105 and the bottom circuit of the isolation plate 201, realizing the complete disconnection of the circuit from the unused state, and avoiding short circuits.

[0071] Better, such as Figure 6 As shown, the petal-shaped post 105c is in the shape of an outwardly extending petal and has a certain degree of elasticity. Inside the post is a protruding convex ring 105c-1 with a hole diameter larger than the size of the connecting wire, which can be used to connect various sizes of connecting wire plug segments. When in use, the connecting wire plug segment can be quickly inserted without having to open the convex ring 105c-1, thus avoiding damage after repeated insertions.

[0072] In addition, such as Figure 7 As shown, a first inclined surface 204a-22 with a downward slope is formed at the rear end of the step block 204a-2, and a fixing member 206 is provided at the rear end of the first inclined surface 204a-22. The fixing member 206 consists of an L-shaped block 206a that cooperates with the first inclined surface 204a-22, and limiting brackets 206b on both sides of the L-shaped block 206a. The limiting brackets 206b can limit the L-shaped block 206a at this position, and a second inclined surface 206a-1 that cooperates with the first inclined surface 204a-22 is formed at the bottom of the L-shaped block 206a. When the step block 204a-2 moves backward, the first inclined surface 204a-22 will lift the second inclined surface 206a-1, thereby lifting the sliding sleeve 205c, compressing the petal-shaped column 105c inward, and clamping the insertion section of the connecting wire.

[0073] Usage process: It can be divided into two steps.

[0074] During the first measurement: the operator activates the unlocking mechanism by pushing the release levers 203b on both sides of the instrument box 101 inward. This causes the claws 203a to unfold outward, releasing the lock on the latch 202c-2. Subsequently, the sliding lever 202c retracts under the elastic force of the large spring 202b, causing the locking block 204a-1 and the ladder block 204a-2, which are locked in it, to move backward. This action first triggers the uncompressed small spring 204b-1, whose elastic force drives the connecting block 204b-2, pushing the sliding seat 105a to move along the trajectory of the L-shaped groove 205b-1. This causes the terminal 105, which was originally in a horizontal state, to rotate counterclockwise to a vertical position, realizing the change from a horizontal to a vertical state. With the rotation, one side of the sliding seat 105a changes from a non-contact state with the outer copper post 205a to a contact state. This continuous action ensures that the wiring between the terminal 105 and the bottom of the isolation plate 201 changes from being disconnected to being closed, thereby realizing the connection of the wiring in one step. Then, as the sliding rod 202c continues to retract, the small spring 204b-1 begins to compress. The sliding sleeve 205c, which is fitted onto the outside of the petal-shaped post 105c, also moves from a horizontal position to a vertical position. The extension rods 205c-1 on both sides of the sliding sleeve 205c rest on the L-shaped block 206a. The L-shaped block 206a is lifted up by the sliding of the first inclined surface 204a-22 and the second inclined surface 206a-1, which in turn lifts up the sliding sleeve 205c. This compresses the petal-shaped post 105c inward, thereby clamping the plug section of the connecting wire and realizing the secondary connection of the line.

[0075] Secondly, during retrieval, sliding the upper sliding button 202c-3 advances the sliding rod 202c, causing the sliding sleeve 205c to descend. This causes the petal-shaped post 105c to automatically open outwards, allowing the external connection wire to quickly detach. Then, the vertically positioned terminal 105 is rotated clockwise to a horizontal position, preventing the sliding seat 105a from contacting the outer copper post 205a, achieving complete separation from the wiring when not in use. Finally, the latch 202c-2 and the claw 203a engage to complete the fixing process.

[0076] In summary, with the measurement unit 100 and the storage unit 200, this device achieves complete separation of the terminal 105 from the wiring when not in use, effectively avoiding the risk of short circuits and quickly retrieving the terminal 105 inside the instrument box 101, preventing dust from accumulating on the inside of the terminal 105 and affecting its normal use. Furthermore, it avoids the damage that may be caused by frequent plugging and unplugging of the terminal 105 in traditional methods, and achieves rapid disconnection and compatibility with various models.

[0077] Importantly, the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A DC universal polarity measuring instrument, characterized in that: include, The measuring unit (100) includes an instrument box (101), a DC meter (102) disposed inside the instrument box (101), a shunt (103) disposed behind the DC meter (102), a resistor (104) disposed on one side of the shunt (103), four sets of terminals (105) disposed on the side of the instrument box (101), a knob (106) disposed on one side of the resistor (104), and a battery (107) disposed on one side of the knob (106). It also includes a storage unit (200) disposed around the terminal (105): The storage unit (200) can fold and store the terminal (105); The storage unit (200) includes an isolation plate (201) disposed in the inner interlayer of the instrument box (101), two sets of trigger components (202) disposed above the isolation plate (201), a buckle (203) disposed on one side of each set of trigger components (202), a lifting component (204) disposed on one side of the trigger components (202), a connecting post (205) disposed on one side of the lifting component (204), and a fastener (206) disposed at the front end of the connecting post (205). The triggering component (202) includes a guide groove (202a) fixedly disposed on the isolation plate (201), a large spring (202b) disposed inside the guide groove (202a), and a sliding rod (202c) disposed at the front end of the large spring (202b). The sliding rod (202c) includes a pull rod (202c-1) disposed at the front end of the large spring (202b), a latch (202c-2) disposed at the front end of the pull rod (202c-1), and a sliding button (202c-3) disposed at the top end of the pull rod (202c-1). The buckle (203) includes a claw (203a) that is movably engaged with the buckle lug (202c-2), and a release rod (203b) disposed at the front end of the claw (203a). The lifting assembly (204) includes a protrusion (204a) fixedly disposed on the side wall of the pull rod (202c-1) and a connector (204b) disposed inside the protrusion (204a). The connecting post (205) includes an outer copper post (205a), a limiting block (205b) disposed inside the outer copper post (205a), and a sliding sleeve (205c) disposed above the outer copper post (205a). The limiting block (205b) includes an L-shaped groove (205b-1) disposed on its inner side; The sliding sleeve (205c) includes extension rods (205c-1) disposed on both sides thereof; The terminal block (105) includes a sliding seat (105a) disposed in the L-shaped groove (205b-1), a copper rod (105b) disposed above the sliding seat (105a), and a petal-shaped post (105c) disposed above the copper rod (105b). A raised ring (105c-1) is provided on the inner side of the petal-shaped column (105c); The sliding sleeve (205c) is slidably fitted onto the outside of the petal-shaped column (105c). The sliding seat (105a) is fixedly connected to the connecting block (204b-2) on one side.

2. The DC universal polarity measuring instrument as described in claim 1, characterized in that: The protrusion (204a) includes a snap-fit ​​block (204a-1) fixedly connected to the pull rod (202c-1), and a step block (204a-2) disposed on one side of the snap-fit ​​block (204a-1). The step block (204a-2) has a sliding groove (204a-21) inside, and one side of the step block (204a-2) is set as a first inclined surface (204a-22).

3. The DC universal polarity measuring instrument as described in claim 2, characterized in that: The connector (204b) includes a small spring (204b-1) fixed to one side of the slide (204a-21) and a connecting block (204b-2) disposed on one side of the small spring (204b-1).

4. The DC universal polarity measuring instrument as described in claim 3, characterized in that: The fastener (206) includes an L-shaped block (206a) disposed on one side of the first inclined surface (204a-22) and a limiting frame (206b) slidably disposed on one side of the L-shaped block (206a). The L-shaped block (206a) includes a second inclined surface (206a-1) disposed at its bottom.

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