CN114783255A - A dynamic magnetic field line demonstration component and dynamic magnetic field line demonstration device - Google Patents

Abstract

The invention provides a dynamic magnetic field line demonstration component, which relates to the field of physical experimental equipment; the dynamic magnetic field line demonstration component includes two stacked transparent cover plates and a display film layer; the display film layer is sealed and arranged on the transparent cover between the plates; the display thin film layer is made of a mixed fluid including nano iron powder and a rust remover; the present invention also proposes a dynamic magnetic field line demonstration device, including the above-mentioned dynamic magnetic field line demonstration component and dynamic magnetic field Line generating mechanism; the dynamic magnetic field line generating mechanism is used to generate a dynamic magnetic field; the dynamic magnetic field line demonstration component is used to demonstrate the magnetic field lines of the dynamic magnetic field; the present invention can demonstrate the dynamics of magnetic field lines in a changing magnetic field Distribution.

Description

A dynamic magnetic field line demonstration component and dynamic magnetic field line demonstration device

technical field

The invention relates to the field of physical experiment equipment, in particular to a dynamic magnetic field line demonstration component and a dynamic magnetic field line demonstration device.

Background technique

Electromagnetism is a very important part of university physics, which studies the phenomena and laws of interaction between electricity and magnetism. According to the point of view of modern physics, the magnetic field is a special substance existing in the space around the moving electric charge except the electric field, and has a strong effect on the moving electric charge located in it. In order to visually reflect the size and distribution of the magnetic field, people have introduced some imagined curves, namely magnetic field lines. The tangent direction of each point on the magnetic field line is used to represent the direction of the magnetic field, and the density of the magnetic field line distribution is used to represent the point. the magnitude of the magnetic field. The current course content not only involves static magnetic field models such as U-shaped permanent magnets, bar-shaped permanent magnets, spherical permanent magnets, etc., but also includes dynamic magnetic field distributions such as energized straight wires, energized solenoid coils, and three-phase alternating current that can change with the magnitude and direction of the current. Magnetic field model. Understanding the basic distribution characteristics of magnetic field lines of these models is the basis for mastering and analyzing magnetic circuits.

In the prior art, the demonstration experiment of the magnetic field line mainly places the magnet on the cardboard, evenly sprinkles iron filings on the cardboard, and taps the cardboard to make the iron filings magnetize and move under the action of the magnetic field, showing the effect of the magnetic field line. shape. However, the iron filings in this method are easily adsorbed to the magnet, which is very inconvenient to clean and recycle after use, and cannot demonstrate the dynamic distribution of the magnetic field lines in the changing magnetic field.

SUMMARY OF THE INVENTION

The invention aims to solve the technical problem that the existing magnetic field line demonstration device cannot demonstrate the dynamic distribution of magnetic field lines in a changing magnetic field.

The present invention provides a dynamic magnetic field line demonstration component, which includes two stacked transparent cover plates and a display film layer; the display film layer is sealed between the transparent cover plates; Made of a mixed fluid of iron powder and rust remover.

Further, the nano iron powder is nano spherical iron powder, and the particle size is 200-500 nm.

The present invention also provides a dynamic magnetic field line demonstration device, comprising the above-mentioned dynamic magnetic field line demonstration component and a dynamic magnetic field line generating mechanism;

The dynamic magnetic field line generating mechanism is used for generating a dynamic magnetic field;

The dynamic magnetic field lines demonstration component is used to demonstrate the magnetic field lines of the dynamic magnetic field.

Further, the dynamic magnetic induction line generating mechanism includes a first dynamic magnetic induction line generating circuit; the first dynamic magnetic induction line generating circuit includes a power-on solenoid, a single-phase AC power supply, and a power-on solenoid switch; the power-on solenoid The coil and the energized solenoid switch are connected in series with the single-phase AC power supply; the transparent cover is provided with an energized solenoid installation hole for installing the energized solenoid; the energized solenoid is pierced through the into the mounting hole of the energized solenoid.

Further, the first dynamic magnetic induction line generating circuit further includes an energized straight wire and an energized straight wire switch; the energized straight wire and the energized straight wire switch are connected in series with the energized solenoid and the energized solenoid. Switches in parallel.

Further, the dynamic magnetic field line generating mechanism further includes a second dynamic magnetic field line generating circuit; the second dynamic magnetic field line generating circuit includes a three-phase AC power supply and a first three-phase AC power supply respectively connected to the first circuit. The phase branch, the second phase branch and the third phase branch; the first phase branch, the second phase branch and the third phase branch are connected in parallel; the first branch includes a series connection the first phase branch switch and the first phase coil; the second phase branch includes the second phase branch switch and the second phase coil connected in series; the third phase branch includes the third phase branch connected in series circuit switch and the third-phase coil; the transparent cover is provided with a first-phase coil mounting hole, a second-phase coil mounting hole and a third-phase coil mounting hole; the first-phase coil mounting hole, the second-phase coil mounting hole, the second-phase coil mounting hole The phase coil mounting holes and the third-phase coil mounting holes are evenly distributed on the same circumference; the first-phase coil, the second-phase coil and the third-phase coil are respectively penetrated on the first-phase coil installation holes, the second-phase coil installation holes and the third-phase coil installation holes.

Further, the dynamic magnetic field line demonstration device also includes a box body and a mounting plate frame;

The inner side of the box body is provided with a limiting rib for supporting the mounting plate frame in the upper end of the box body; the dynamic magnetic field line generating mechanism is arranged in the box body;

The mounting plate frame is detachably arranged on the limiting rib; the mounting plate frame includes a C-shaped mounting plate and a closed beam; the inner side of the C-shaped mounting plate is oppositely provided with a guide groove; the dynamic magnetic Two ends of the induction line demonstration component are respectively inserted in the guide groove; the closed beam is detachably connected with the C-shaped mounting plate, so as to limit the dynamic magnetic induction line demonstration component in the guide groove .

Further, the inner side of the C-shaped mounting plate is provided with pin holes oppositely; the two ends of the closed beam are respectively provided with mounting holes; A position slot hole, the position limit slot hole is arranged along the length direction of the closed beam; the installation hole is provided with a spring pin and a spring used in cooperation with the pin hole; one end of the spring pin is used for inserting In the pin hole, the other end is in contact with the spring; the spring is in a compressed state; a lever is provided on the side wall of the spring pin, and the lever extends through the limiting slot hole to the desired position. above the closed beam; the closed beam is detachably connected with the C-shaped mounting plate through the spring pin.

Further, the two ends of the C-shaped mounting plate are respectively provided with limit slots; the two ends of the closed beam are respectively provided with limit blocks used in cooperation with the limit slots for inserting in the limit blocks. The limiting slot cooperates with the limiting block to support the closing beam on the C-shaped mounting plate, so that the spring pin and the pin hole are coaxially arranged.

Further, the mounting plate frame is provided with a handle, which is used to facilitate taking out the mounting plate frame.

The beneficial effects brought by the technical solutions provided by the embodiments of the present invention are: the dynamic magnetic field line demonstration assembly in the embodiments of the present invention includes two stacked transparent cover plates and a display film layer; wherein, the display film layer is sealed Set between the transparent cover plates, the display film layer is made of a mixed fluid including nano iron powder and rust remover; when demonstrating the magnetic field lines generated by the dynamic magnetic field, the dynamic magnetic field lines demonstration component is placed. In the dynamic magnetic field, under the action of the dynamic magnetic field, the nano-iron powder is rapidly magnetized and moved rapidly, so that the density of the different positions of the display film layer changes with the change of the magnetic field. In the present invention, the interference phenomenon is generated, and the dynamic thin film interference fringes as clear as the magnetic field lines appear, so as to realize the demonstration of the dynamic magnetic field lines; the dynamic magnetic field lines demonstration component in the present invention has a quick response to the dynamic magnetic field, and the demonstration effect is good; in addition, Because the nano iron powder is distributed in the rust remover, the nano iron powder is not easy to rust, and the service life of the nano iron powder is prolonged.

Description of drawings

1 is a schematic three-dimensional structure diagram of a dynamic magnetic field line demonstration component in an embodiment of the present invention;

2 is a schematic three-dimensional structure diagram of a dynamic magnetic field line demonstration device in an embodiment of the present invention;

FIG. 3 is a schematic three-dimensional structure diagram of the box cover 101 in the open state in the dynamic magnetic field line demonstration device of FIG. 1;

FIG. 4 is a schematic three-dimensional structure diagram of the box body 1 in the dynamic magnetic field line demonstration device of FIG. 3;

FIG. 5 is a schematic diagram of the combined structure of the mounting plate frame 3 and the magnetic field line display assembly 2 in the dynamic magnetic field line demonstration device of FIG. 3;

Fig. 6 is the three-dimensional structure schematic diagram when energized solenoid coil 6, energized straight wire 9, first-phase coil 17, second-phase coil 19 and third-phase coil 21 are installed on the dynamic magnetic field line demonstration assembly of Fig. 1;

FIG. 7 is a three-dimensional schematic diagram of the mounting plate frame 3 in the dynamic magnetic field line demonstration device of FIG. 3;

FIG. 8 is a schematic three-dimensional structural diagram of the C-shaped mounting plate 31 in the mounting plate frame 3 of FIG. 7;

FIG. 9 is a schematic three-dimensional structural diagram of the closed beam 32 in the mounting plate frame 3 of FIG. 7;

Figure 10 is a side view of the closing beam 32 in Figure 9;

FIG. 11 is a schematic cross-sectional structure diagram of the closed beam 32 of FIG. 10 in the direction A-A;

FIG. 12 is a schematic diagram of the combined structure of the spring pin 321, the lever 322 and the spring 326 in the closed beam 32 of FIG. 11;

FIG. 13 is a schematic three-dimensional structure diagram of the spring pin 321 in FIG. 12;

14 is a schematic diagram of a first dynamic magnetic field line generating circuit in a magnetic field line demonstration device according to an embodiment of the present invention;

15 is a schematic diagram of a second dynamic magnetic field line generating circuit in a magnetic field line demonstration device according to an embodiment of the present invention;

Among them, 1. box body; 101, box cover; 102, limit rib; 2, dynamic magnetic field line demonstration component; 201, transparent cover plate; 202, installation hole for energized solenoid; 203, installation hole for energized straight wire; 204, first-phase coil mounting hole; 205, second-phase coil mounting hole; 206, third-phase coil mounting hole; 207, display film layer; 3, mounting plate frame; 31, C-type mounting plate; 311, guide slot ;312, handle; 313, pin hole; 314, limit slot; 32, closed beam; 321, spring pin; 322, lever; 323, limit slot; 324, limit block; 325, mounting hole; 326, spring; 327, threaded mounting hole; 328, limit rod; 4, single-phase AC power supply; 5, adjustable resistance box; 6, energized solenoid; 7, first protection resistor; 8, energized solenoid switch; 9. Powered straight wire; 10. Second protection resistor; 11. Powered straight wire switch; 12. Circuit switch; 13. Three-phase AC power supply; 14. First-phase branch switch; 15. Second-phase branch switch; 16. Third-phase branch switch; 17. First-phase coil; 18. First-phase protection resistor; 19. Second-phase coil; 20. Second-phase protection resistor; 21. Third-phase coil; 22. Third-phase Phase protection resistor; 23. Resistance adjustment knob.

Detailed ways

The preferred embodiments of the present invention are specifically described below with reference to the accompanying drawings, wherein the accompanying drawings constitute a part of the present application, and together with the embodiments of the present invention, are used to explain the principles of the present invention, but are not used to limit the scope of the present invention.

Referring to FIG. 1 , an embodiment of the present invention provides a dynamic magnetic field line demonstration component, including two stacked transparent cover plates 201 and a display film layer 207 ; the display film layer 207 is sealed between the transparent cover plates 201 ; The display film layer 207 is made of a mixed fluid including nano-iron powder and a rust remover.

After the nano iron powder and the rust remover are evenly mixed, the mixed fluid is obtained, and the mixed fluid is coated on one of the transparent cover plates 201, and the other transparent cover plate 201 is covered, so that the display The thin film layer 207 is located between the transparent cover plates 201 and seals the edges of the transparent cover plates 201 with adhesive tape.

Exemplarily, in this embodiment, the transparent cover plate 201 is a transparent glass cover plate.

In order to better disperse the nano iron powder in the rust remover, the mass ratio of the nano iron powder to the rust remover is 18-55:100.

Exemplarily, in this embodiment, the mass ratio of the nano iron powder and the rust remover is 28:100; the rust remover is WD-40 rust remover.

In order to make the nano-iron powder in the display film layer 207 more sensitive to the change of the magnetic field, the nano-iron powder is nano-spherical iron powder with a particle size of 200-500 nm.

Referring to FIGS. 2 to 8 , an embodiment of the present invention further provides a dynamic magnetic field line demonstration device, including the above-mentioned dynamic magnetic field line demonstration component 2 , a dynamic magnetic field line generating mechanism, a box 1 and a mounting plate frame 3 ;

The dynamic magnetic field line generating mechanism is arranged in the box body 1 for generating a dynamic magnetic field;

The dynamic magnetic field line demonstration component 2 is used to demonstrate the magnetic field lines of the dynamic magnetic field;

The inner side of the box body 1 is provided with a limiting rib 102 for supporting the mounting plate frame 3 on the upper end of the box body 1;

The mounting plate frame 3 is detachably arranged on the limiting rib 102; the mounting plate frame 3 includes a C-shaped mounting plate 31 and a closed beam 32; the inner side of the C-shaped mounting plate 31 is oppositely provided with a guide groove 311; the dynamic magnetic field line demonstration The two ends of the assembly 2 are respectively inserted in the guide grooves 311 ; the closed beam 32 is detachably connected to the C-shaped mounting plate 31 for confining the dynamic magnetic field line demonstration assembly 2 in the guide grooves 311 .

Specifically, referring to FIGS. 8 to 12 , the inner side of the C-shaped mounting plate 31 is oppositely provided with pin holes 313 ; both ends of the closed beam 32 are respectively provided with mounting holes 325 ; The limit slot hole 323 communicated with the hole 325, the limit slot hole 323 is arranged along the length direction of the closed beam 32; the installation hole 325 is provided with a spring pin 321 and a spring 326 used in conjunction with the pin hole 313; one end of the spring pin 321 is used for Inserted in the pin hole 313, the other end is in contact with the spring 326; the other end of the spring pin 321 is provided with a limit rod 328, and the limit rod 328 is coaxial with the spring pin 321; one end of the spring 326 is sleeved on the limit On the rod 328; the spring 326 is in a compressed state; the side wall of the spring pin 321 is provided with a lever 322, and the lever 322 extends to the top of the closed beam 32 through the limit slot 323; the closed beam 32 is connected to the C type through the spring pin 321 The mounting plate 31 is detachably connected.

12 and 13, in order to facilitate the installation of the spring pin 321 and the lever 322; the lower end of the lever 322 is provided with a threaded connection part (not shown in the figure); The lever 322 is threadedly connected with the spring pin 321; when installing, first install the spring 326 and the spring pin 321 in the mounting hole 325 in sequence, and then insert the lever 322 through the limit slot 323 It is set to the mouth of the threaded mounting hole 327 and screwed into the lever 322 to realize the installation of the spring pin 321 and the lever 322, so that the spring 326 is in a compressed state.

8 and 9, in order to facilitate the alignment of the spring pins 321 with the pin holes 313, the two ends of the C-shaped mounting plate 31 are respectively provided with limiting grooves 314; The limit block 324 is used to be inserted into the limit slot 314; the limit slot 314 cooperates with the limit block 324 to support the closed beam 32 on the C-shaped mounting plate 31, so that the spring pin 321 and the pin hole 313 Coaxial setup.

Referring to FIG. 8 , in order to facilitate taking out the mounting plate frame 3 ; a handle 312 is provided on the mounting plate frame 3 .

Referring to FIG. 4 , the box body 1 is further provided with a box cover 101 , and the box cover 101 is rotatably connected to the box body 1 through a rotating shaft for closing or opening the opening of the box body 1 .

Referring to FIG. 14 , the dynamic magnetic field line generating mechanism includes a first dynamic magnetic field line generating circuit; the first dynamic magnetic field line generating circuit includes an energized solenoid 6 , a single-phase AC power supply 4 and an energized solenoid switch 8 ; The energized solenoid 6 and the energized solenoid switch 8 are connected in series with the single-phase AC power supply 4; a first protection resistor 7 is provided between the energized solenoid 6 and the energized solenoid switch 8; the energized solenoid switch 8 is connected to the single-phase AC power supply A circuit switch 12 and an adjustable resistance box 5 are arranged between 4; the transparent cover plate 201 is provided with a energized solenoid coil mounting hole 202 for installing the energized solenoid coil 6; The energized solenoid switch 8, the circuit switch 12 and the resistance adjustment knob 23 of the adjustable resistance box 5 are all installed on the C-type mounting plate 31.

When demonstrating the distribution of the dynamic magnetic field lines of the energized solenoid, first disconnect the circuit switch 12 and the energized straight wire switch 11; adjust the resistance value of the adjustable resistance box 5 to the maximum, and turn on the energized solenoid switch 8 and the circuit switch 12; Slowly adjust the resistance value of the adjustable resistance box 5 to an appropriate value; under the action of the single-phase AC power supply 4, the magnitude and direction of the current passing through the energized solenoid 6 periodically change, resulting in the magnetic field strength and magnetic field around the energized solenoid 6. The direction of the sense line changes periodically, so that the nano-iron powder in the dynamic magnetic sense line demonstration component 2 is rapidly magnetized and moved, so that the density of different positions of the display film layer 207 changes with the change of the magnetic field, which is generated under the action of light. The interference phenomenon, the dynamic thin film interference fringes as clear as the magnetic field lines appear, so as to realize the demonstration of the dynamic magnetic field lines of the energized solenoid.

Further, the first dynamic magnetic induction line generating circuit also includes a energized straight wire 9 and an energized straight wire switch 11; A second protection resistor 10 is provided between the energized straight wire 9 and the energized straight wire switch 11; the transparent cover plate 201 is provided with an energized straight wire mounting hole 203; In the first dynamic magnetic field line generating circuit; the energized straight wire switch 11 is installed on the C-type mounting plate 31 .

When demonstrating the dynamic magnetic field line distribution of the energized straight wire, first turn off the circuit switch 12, the energized straight wire switch 11 and the energized solenoid switch 8; adjust the resistance value of the adjustable resistance box 5 to the maximum, and turn on the energized straight wire switch 11 and circuit switch 12; then slowly adjust the resistance of the adjustable resistance box 5 to an appropriate value; under the action of the single-phase AC power supply 4, the magnitude and direction of the current through the energized straight wire 9 change periodically, resulting in the energized straight wire The magnetic field strength around 9 and the direction of the magnetic field lines change periodically, so that the nano-iron powder in the dynamic magnetic field line demonstration component 2 is rapidly magnetized and moved, so that the density of different sites of the display film layer 207 changes with the change of the magnetic field , under the action of light, interference phenomenon occurs, and dynamic thin film interference fringes as clear as magnetic field lines appear, so as to realize the demonstration of dynamic magnetic field lines of energized straight wires.

Referring to FIG. 15 , the dynamic magnetic induction line generating mechanism further includes a second dynamic magnetic induction line generating circuit; A phase branch, a second phase branch and a third phase branch; the first phase branch, the second phase branch and the third phase branch are connected in parallel; the first phase branch includes The first phase branch switch 14, the first phase coil 17 and the first phase protection resistor 18 are connected in series; the second phase branch includes the second phase branch switch 15, the second phase coil 19 and the second phase branch connected in series protection resistor 20; the third-phase branch circuit includes a third-phase branch switch 16, a third-phase coil 21 and a third-phase protection resistor 22 connected in series; the transparent cover plate 201 is provided with a first-phase coil installation hole 204, The second-phase coil mounting holes 205 and the third-phase coil mounting holes 206; the first-phase coil mounting holes 204, the second-phase coil mounting holes 205 and the third-phase coil mounting holes 206 are evenly distributed on the same circumference; the first-phase coil mounting holes 204 are evenly distributed on the same circumference; 17. The second-phase coil 19 and the third-phase coil 21 are respectively drilled in the first-phase coil mounting hole 204, the second-phase coil mounting hole 205 and the third-phase coil mounting hole 206; the first-phase branch switches 14, Both the second phase branch switch 15 and the third phase branch switch 16 are mounted on the C-type mounting plate 31 .

When demonstrating the three-phase alternating current dynamic magnetic field line distribution, first disconnect the circuit switch 12, the energized straight wire switch 11 and the energized solenoid switch 8; turn on the first phase branch switch 14, the second phase branch switch 15 and the third phase branch switch 15. The phase branch switch 16; the first phase coil 17, the second phase coil 19 and the third phase coil 21 are connected with three-phase asynchronous currents, and the phase difference between the currents is 2π/3. The magnitude and direction of the current in the first-phase coil 17, the second-phase coil 19 and the third-phase coil 21 change periodically, so that the direction and magnitude of the resultant magnetic field at the center position change periodically with time, so that the dynamic magnetic field lines in the demonstration component 2 The nano-iron powder is rapidly magnetized and moved, so that the density of different positions of the display film layer 207 changes with the change of the magnetic field, and interference phenomenon occurs under the action of light, and dynamic film interference fringes as clear as magnetic field lines appear. Demonstration of three-phase alternating current dynamic magnetic field lines.

The dynamic magnetic field line demonstration device in this embodiment has a quick response to the magnetic field, and the demonstration effect is remarkable. It can effectively solve the problems in the prior art that the iron filings are easy to oxidize, difficult to recover, slow to move, fuzzy in phenomenon, and limited in the static magnetic field for testing. It is used as a demonstration of dynamic magnetic field lines in teaching.

The parts not covered above are applicable to the prior art.

In this document, the related terms such as front, rear, upper and lower are defined by the positions of the components in the drawings and the positions between the components, which are only for the clarity and convenience of expressing the technical solution. It should be understood that the use of the locative words should not limit the scope of protection claimed in this application.

The above-described embodiments and features of the embodiments herein may be combined with each other without conflict.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection of the present invention. within the range.

Claims (10)

1. A dynamic magnetic field line demonstration assembly, characterized in that it comprises two stacked transparent cover plates and a display film layer; the display film layer is sealed and arranged between the transparent cover plates; the display film layer Made of mixed fluid including nano iron powder and rust remover. 2 . The dynamic magnetic field line demonstration component according to claim 1 , wherein the nano-iron powder is nano-spherical iron powder with a particle size of 200-500 nm. 3 . 3. A dynamic magnetic field line demonstration device, characterized in that, comprising a dynamic magnetic field line demonstration assembly and a dynamic magnetic field line generating mechanism as described in claim 1 or 2; The dynamic magnetic field line generating mechanism is used for generating a dynamic magnetic field; The dynamic magnetic field lines demonstration component is used to demonstrate the magnetic field lines of the dynamic magnetic field. 4 . The dynamic magnetic field line demonstration device according to claim 3 , wherein the dynamic magnetic field line generating mechanism comprises a first dynamic magnetic field line generating circuit; the first dynamic magnetic field line generating circuit comprises an electrified solenoid. a coil, a single-phase AC power supply, and a power-on solenoid switch; the power-on solenoid and the power-on solenoid switch are connected in series with the single-phase AC power supply; the transparent cover is provided with a power-on solenoid for installing the power-on solenoid The energized solenoid coil installation hole; the energized solenoid coil is penetrated in the energized solenoid coil installation hole. 5 . The dynamic magnetic induction line demonstration device according to claim 4 , wherein the first dynamic magnetic induction line generating circuit further comprises an energized straight wire and an energized straight wire switch; the energized straight wire and the energized straight wire. The wire switch is connected in parallel with the energizing solenoid and the energizing solenoid switch after being connected in series. 6. The dynamic magnetic induction line demonstration device according to claim 3, wherein the dynamic magnetic induction line generating mechanism further comprises a second dynamic magnetic induction line generating circuit; the second dynamic magnetic induction line generating circuit comprises three A phase AC power supply and a first phase branch, a second phase branch and a third phase branch respectively connected to the three-phase AC power supply; the first phase branch, the second phase branch and the The third phase branch is connected in parallel; the first branch includes the first phase branch switch and the first phase coil connected in series; the second phase branch includes the second phase branch switch and the second phase connected in series coil; the third-phase branch circuit includes a third-phase branch switch and a third-phase coil connected in series; the transparent cover plate is provided with a first-phase coil installation hole, a second-phase coil installation hole and a third-phase coil mounting holes; the first-phase coil mounting holes, the second-phase coil mounting holes and the third-phase coil mounting holes are evenly distributed on the same circumference; the first-phase coil, the second-phase coil and The third-phase coils are respectively penetrated in the first-phase coil mounting holes, the second-phase coil mounting holes, and the third-phase coil mounting holes. 7. The dynamic magnetic field line demonstration device according to claim 3, further comprising a box body and a mounting plate frame; The inner side of the box body is provided with a limiting rib for supporting the mounting plate frame in the upper end of the box body; the dynamic magnetic field line generating mechanism is arranged in the box body; The mounting plate frame is detachably arranged on the limiting rib; the mounting plate frame includes a C-shaped mounting plate and a closed beam; the inner side of the C-shaped mounting plate is oppositely provided with a guide groove; the dynamic magnetic Two ends of the induction line demonstration component are respectively inserted in the guide groove; the closed beam is detachably connected with the C-shaped mounting plate, so as to limit the dynamic magnetic induction line demonstration component in the guide groove . 8 . The dynamic magnetic field line demonstration device according to claim 7 , wherein the inner side of the C-shaped mounting plate is oppositely provided with pin holes; the two ends of the closed beam are respectively provided with mounting holes; the closed beam Both ends of the upper side of the upper side are respectively provided with limit slot holes communicating with the installation holes, and the limit slot holes are arranged along the length direction of the closed beam; A spring pin and a spring; one end of the spring pin is used to be inserted into the pin hole, and the other end is in contact with the spring; the spring is in a compressed state; a dial is provided on the side wall of the spring pin The lever is extended to the top of the closed beam through the limit slot hole; the closed beam is detachably connected to the C-shaped mounting plate through the spring pin. 9 . The dynamic magnetic field line demonstration device according to claim 8 , wherein limit slots are respectively provided at both ends of the C-shaped mounting plate; The limit block used in conjunction with the groove is used to be inserted in the limit groove; the limit groove cooperates with the limit block and is used to support the closed beam on the C-shaped mounting plate, The spring pins are arranged coaxially with the pin holes. 10 . The dynamic magnetic field line demonstration device according to claim 7 , wherein a handle is provided on the mounting plate frame to facilitate taking out the mounting plate frame. 11 .

Images