Anti-inrush resistor

Abstract

The application relates to an overcurrent-preventing resistor, which comprises a shell and a resistance coil, the bottom of the shell is internally provided with a bobbin and externally provided with a first pin and a second pin, the resistance coil is electrically connected to the first pin and the second pin, the resistance coil is sleeved on the bobbin and electrically insulated from the bobbin, the bobbin is internally provided with a magnetic piece, the magnetic piece is in sliding connection with the bobbin, the magnetic poles of the magnetic piece are distributed along the axis of the bobbin, the magnetic piece is electrically connected with the bobbin, the top of the inside of the shell is provided with an electric contact opposite to the bobbin, the top of the outside of the shell is provided with an indicating lamp electrically connected with the electric contact, and the inside of the shell is provided with a wire for electrically connecting the second pin. The application has the functions of quickly determining overcurrent in a laboratory and giving a warning.

Description

Technical Field

[0001] This application relates to the field of resistors, and more particularly to an overcurrent protection resistor. Background Technology

[0002] A resistor is a current-limiting element used in circuits. Wire-wound resistors are a common type of resistor and are widely used in various current-limiting circuits, voltage divider circuits, bleeder circuits, and bias circuits. These circuits often have relatively high power, and the resistor is always in a heat-generating state when the circuit is limiting current, so the resistor is always in a high-temperature state.

[0003] However, in a laboratory environment, due to students' lack of experience or improper operation, resistors are sometimes connected to excessively high voltage sources without being detected in time. This leads to overcurrent, overheating, and damage to the resistors, and subsequent troubleshooting takes a lot of time, affecting the efficiency of classroom experiments. To avoid this problem, an ammeter is usually connected in series in the circuit or a voltmeter is connected in parallel across the resistor. However, this is not only inconvenient to operate, but may also damage the voltmeter and ammeter. Summary of the Invention

[0004] In order to quickly detect overcurrent and issue a warning, this application provides an overcurrent protection resistor.

[0005] This application provides an overcurrent protection resistor, which adopts the following technical solution:

[0006] An overcurrent protection resistor includes a housing and a resistance coil. A winding tube is disposed inwardly at the bottom of the housing, and a first pin and a second pin are disposed outwardly. The resistance coil is electrically connected to the first pin and the second pin. The resistance coil is sleeved on the winding tube and electrically insulated from it. A magnetic element is disposed inside the winding tube, and the magnetic element is slidably connected to the winding tube with its magnetic poles distributed along the axis of the winding tube. The magnetic element is electrically connected to the winding tube. An electrical contact is disposed at the top inside the housing, opposite to the winding tube. An indicator light is disposed at the top outside the housing, electrically connected to the electrical contact. A wire for electrically connecting the second pin is disposed inside the housing.

[0007] By adopting the above technical solution, the housing encloses the resistor coil, protecting the internal resistor coil. The first and second pins are connected in series with the resistor coil for connection to external circuits. When the resistor coil is energized, a magnetic field is generated inside the coil. The direction of this magnetic field is related to the direction of current flow, therefore the resistor coil needs to be energized according to a predetermined current direction. When the magnetic field is generated inside the resistor coil, it exerts a force on the magnetic component towards the top or bottom of the housing. When the resistor coil is energized according to the predetermined current direction, the magnetic field exerts a force on the magnetic component towards the top of the housing. When the current intensity exceeds a threshold, the magnetic component will overcome gravity and move towards the electrical contact under the influence of magnetic force. At this time, the winding tube and the electrical contact are electrically connected through the magnetic component, and the indicator light is energized to indicate the current overcurrent. This solution allows for the integration of an overcurrent alarm device within the resistor using a simple structure, eliminating the need for extensive external circuitry, which is very convenient. Furthermore, the circuit from the first pin to the winding tube to the magnetic component to the electrical contact to the indicator light to the second pin can also shunt the current in the resistor coil, reducing the risk of long-term overcurrent causing the resistor coil to burn out.

[0008] Optionally, the inner surface of the winding tube is provided with a first conductive layer, and the outer surface of the magnetic component is provided with a second conductive layer, wherein the first conductive layer and the second conductive layer are slidably connected.

[0009] By adopting the above technical solution, the winding tube and the magnetic component can be electrically connected through the first conductive layer and the second conductive layer. The first conductive layer is located on the inner side of the winding tube, avoiding the risk of short circuit when the enamel coating of the resistance coil is damaged. The second conductive layer on the outside of the magnetic component overcomes the poor conductivity of the ferrite itself.

[0010] Optionally, the housing includes a base, a tube, and a top plate. The tube is fixedly connected to the base, the top plate is fixedly installed on the tube, the winding tube is installed on the base, and the electrical contacts are installed on the top plate.

[0011] By adopting the above technical solution, the shell is divided into multiple components, so that each component can be manufactured and assembled separately.

[0012] Optionally, the axial length of the winding tube is less than the distance from the base to the electrical contact.

[0013] By adopting the above technical solution, short circuits between the winding tube and the electrical contacts can be avoided.

[0014] Optionally, the sum of the axial length of the winding tube and the axial length of the magnetic element in the winding tube is greater than the distance from the base to the electrical contact.

[0015] By adopting the above technical solution, the risk of the magnetic component detaching from the winding tube when sliding upwards can be avoided.

[0016] Optionally, the magnetic field generated in the winding tube by the resistor coil when a current in a predetermined direction passes through it repels the magnetic poles of the magnetic component near the base.

[0017] By adopting the above technical solution, when the resistor coil is energized in the predetermined current direction, the magnetic field generates a force on the magnetic component toward the top of the housing.

[0018] Optionally, the force exerted by the resistor coil on the magnetic component in the axial direction away from the base when the rated current passes through it is less than the weight of the magnetic component.

[0019] By adopting the above technical solution, when the current intensity is less than the threshold, the magnetic component will not move towards the electrical contact under the action of magnetic force, overcoming gravity.

[0020] Optionally, when the current passing through the resistor coil exceeds a threshold current value, the force exerted by the magnetic field generated by the resistor coil on the magnetic component in the axial direction away from the base is less than the gravity of the magnetic component, wherein the threshold current is greater than the rated current.

[0021] By adopting the above technical solution, when the current intensity exceeds the threshold, the magnetic component will overcome gravity and move toward the electrical contact under the action of magnetic force.

[0022] Optionally, the first pin and the second pin are disposed on the base.

[0023] By adopting the above technical solution, the first pin and the second pin are used to connect to external circuits.

[0024] Optionally, a positioning ring groove is provided on the base, the shape of which is adapted to the shape of the end of the tube near the base, and the end of the tube near the base is embedded in the positioning ring groove.

[0025] By adopting the above technical solution, the positioning ring groove can position and fix the pipe body during installation, and the pipe body and the base can be easily assembled and connected.

[0026] In summary, this application includes at least one of the following beneficial technical effects:

[0027] 1. Suitable for laboratory environments, it can promptly light up and alarm when students make mistakes, avoiding the need for setting up a large number of peripheral circuits.

[0028] 2. It can promptly divert excessive current when students make mistakes, reducing the risk of resistor burnout. Attached Figure Description

[0029] Figure 1 This is an overall schematic diagram of an overcurrent protection resistor in an embodiment of this application.

[0030] Figure 2 This is an exploded view of an overcurrent protection resistor in an embodiment of this application.

[0031] Figure 3 This is a cross-sectional view of an overcurrent protection resistor in an embodiment of this application.

[0032] Explanation of reference numerals in the attached figures:

[0033] 1. Housing; 101. First pin; 102. Second pin; 103. Base; 104. Tube body; 105. Top plate; 106. Positioning ring groove; 2. Resistor coil; 3. Winding tube; 301. First conductive layer; 4. Magnetic component; 401. Second conductive layer; 5. Electrical contact; 6. Indicator light; 7. Wire. Detailed Implementation

[0034] The present application will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the application and are not intended to limit the scope of the application.

[0035] In the following description, numerous specific details are set forth for purposes of explanation in order to provide a thorough understanding of the inventive concept. As part of this specification, some of the accompanying drawings of this disclosure are block diagrams illustrating structures and devices to avoid complicating the disclosed principles. For clarity, not all features of the actual embodiment need to be described. Furthermore, the language used in this disclosure has been primarily chosen for readability and instructional purposes and may not have been chosen to define or limit the subject matter of the invention, thus requiring the necessary claims to determine such inventive subject matter. References to “an embodiment” or “an embodiment” in this disclosure mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment, and multiple references to “an embodiment” or “an embodiment” should not be construed as necessarily referring to the same embodiment.

[0036] Unless explicitly defined, the terms “a,” “an,” and “the” are not intended to refer to a singular entity, but rather to include a general category whose specific examples can be used for illustration. Therefore, the use of the terms “a” or “an” can mean any number of at least one, including “a,” “one or more,” “at least one,” and “one or more.” The term “or” means any of the options and any combination of the options, including all options unless explicitly indicated that the options are mutually exclusive. The phrase “at least one of” when combined with a list of items refers to a single item in the list or any combination of items in the list. The phrase does not require all items listed unless explicitly defined as such.

[0037] This application discloses an overcurrent protection resistor. (Refer to...) Figure 1 The overcurrent protection resistor includes a housing 1 and a resistance coil 2. The housing 1 is used to protect the internal resistance coil 2.

[0038] The housing 1 includes a base 103, a tube 104, and a top plate 105. In different embodiments, the shapes of the base 103, tube 104, and top plate 105 may differ. In this embodiment, the base 103 is disc-shaped, the tube 104 is cylindrical, and the top plate 105 is disc-shaped. The diameter of the base is larger than the diameter of the tube 104, and the diameter of the tube 104 matches the diameter of the top plate 105. In different embodiments, the base 103 and the tube 104 can be connected in different ways, such as by adhesive bonding, snap-fitting, or threaded connection. To improve the internal sealing of the housing 1, the base 103 is provided with a positioning ring groove 106 for the tube 104 to be inserted. The positioning ring groove 106 is adapted to the shape of the end of the tube 104. After the tube 104 is inserted into the positioning ring groove 106, it is bonded to the base with epoxy resin. In different embodiments, the top plate 105 and the tube 104 can be connected in different ways. As an example, in the embodiment of this application, epoxy resin is used to bond the top plate 105 and the tube 104 so that the top plate 105 and the tube 104 cooperate to form an inverted cylinder.

[0039] The base 103 has a first pin 101 and a second pin 102 on the side opposite to the tube body 104. The first pin 101 and the second pin 102 are electrically connected to the resistor coil 2, respectively. When the first pin 101 and the second pin 102 are connected to an external circuit, the resistor coil 2 will be energized. A winding tube 3 is provided on the side of the base 103 near the tube body 104. The winding tube 3 is a round tube and is fixedly mounted on the base 103. In different embodiments, the winding tube 3 and the base 103 can be connected in different ways, such as one end of the winding tube 3 being threaded or glued to the base 103. In this way, the winding tube 3 can position the resistor coil 2 radially on the base 103.

[0040] The resistance coil 2 is a cylindrical toroidal coil, and the resistance wire is enameled wire wound in multiple turns in one direction. The resistance coil 2 is sleeved on the winding tube 3 and electrically insulated from the winding tube 3. As an example, the outer wall of the winding tube 3 is provided with an insulating coating.

[0041] A magnetic element 4 is disposed inside the winding tube 3, and the magnetic element 4 is slidably connected to the winding tube 3, with its magnetic poles arranged along the axis of the winding tube 3. To increase the magnetic field strength, the magnetic element 4 is made of neodymium alloy magnet. A first conductive layer 301 is disposed on the inner surface of the winding tube 3, and a second conductive layer 401 is disposed on the outer surface of the magnetic element 4, with the first conductive layer 301 and the second conductive layer 401 slidably connected. As an example, the magnetic element 4 is cylindrical, and both the first conductive layer 301 and the second conductive layer 401 are smooth copper layers. When a current in a predetermined direction passes through the resistance coil 2, the magnetic field generated in the winding tube 3 repels the magnetic poles of the magnetic element 4 near the base 103. When a rated current passes through the resistance coil 2, the force exerted on the magnetic element 4 in the axial direction of the winding tube 3 away from the base 103 is less than the weight of the magnetic element 4. When the current passing through the resistor coil 2 exceeds the threshold current value, the magnetic field generated by the resistor coil 2 exerts a force on the magnetic component 4 in the axial direction away from the base 103, which is less than the gravity of the magnetic component 4. The threshold current is greater than the rated current.

[0042] An electrical contact 5 is provided on the side of the top plate 105 near the base 103, which is opposite to the winding tube 3. The axial length of the winding tube 3 is less than the distance from the base 103 to the electrical contact 5, and the sum of the axial length of the winding tube 3 and the axial length of the magnetic component 4 of the winding tube 3 is greater than the distance from the base 103 to the electrical contact 5.

[0043] For example, if the first pin 101 is connected to the positive terminal and the second pin 102 is connected to the negative terminal, and the resistor coil 2 is viewed from the top plate 105 towards the base 103, the current in the resistor coil 2 will flow counterclockwise. Since the N pole of the magnetic component 4 is closer to the base 103 than the S pole, when the current through the resistor coil 2 exceeds the threshold current value, the magnetic component 4 will overcome gravity under the influence of magnetic force and move towards the electrical contact 5 until the second conductive layer 401 contacts the electrical contact 5. When the current through the resistor coil 2 decreases below the threshold current value, the magnetic component 4 will fall back to the bottom of the winding tube 3 under the influence of gravity.

[0044] An indicator light 6, which is electrically connected to the electrical contact 5, is provided on the top of the exterior of the housing 1, and a wire 7 for electrically connecting the second pin 102 is provided inside the housing 1.

[0045] The implementation principle of an overcurrent protection resistor in this application embodiment is as follows:

[0046] When resistor coil 2 is energized, a magnetic field is generated inside it. The direction of this magnetic field is related to the direction of current flow in resistor coil 2, therefore resistor coil 2 needs to be energized according to the predetermined current direction. When the magnetic field generated inside resistor coil 2 is activated, it will exert a force on magnetic component 4 towards the top or bottom of housing 1. When resistor coil 2 is energized according to the predetermined current direction, the magnetic field exerts a force on magnetic component 4 towards the top of housing 1, and when the current intensity exceeds the threshold, magnetic component 4 will move towards electrical contact 5 under the action of magnetic force, overcoming gravity. At this time, winding tube 3 and electrical contact 5 are electrically connected through magnetic component 4, and indicator light 6 is energized to indicate the current overcurrent. This scheme allows for the integration of an overcurrent alarm device within the resistor through a simple structure, without the need for a large number of external peripheral circuits, which is very convenient. In addition, the circuit from first pin 101 to winding tube 3 to magnetic component 4 to electrical contact 5 to indicator light 6 to wire 7 to second pin 102 can also shunt current into resistor coil 2, reducing the risk of long-term overcurrent causing resistor coil 2 to burn out.

[0047] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. An overcurrent protection resistor, characterized in that, The device includes a housing (1) and a resistance coil (2). A winding tube (3) is disposed inwardly at the bottom of the housing (1), and a first pin (101) and a second pin (102) are disposed outwardly. The resistance coil (2) is electrically connected to the first pin (101) and the second pin (102). The resistance coil (2) is sleeved on the winding tube (3) and electrically insulated from it. A magnetic element (4) is disposed inside the winding tube (3). The magnetic element (4) is slidably connected to the winding tube (3), and the magnetic poles of the magnetic element (4) are distributed along the axis of the winding tube (3). The magnetic component (4) is electrically connected to the winding tube (3). An electrical contact (5) opposite to the winding tube (3) is provided on the top inside the housing (1). An indicator light (6) electrically connected to the electrical contact (5) is provided on the top outside the housing (1). A wire (7) for electrically connecting the second pin (102) is provided inside the housing (1). A first conductive layer (301) is provided on the inner side of the winding tube (3). A second conductive layer (401) is provided on the outer surface of the magnetic component (4). The first conductive layer (301) and the second conductive layer (401) are slidably connected.

2. The overcurrent protection resistor according to claim 1, characterized in that, The housing (1) includes a base (103), a tube (104) and a top plate (105). The tube (104) is fixedly connected to the base (103), the top plate (105) is fixedly installed on the tube (104), the winding tube (3) is installed on the base (103), and the electrical contact (5) is installed on the top plate (105).

3. The overcurrent protection resistor according to claim 2, characterized in that, The axial length of the winding tube (3) is less than the distance from the base (103) to the electrical contact (5).

4. The overcurrent protection resistor according to claim 3, characterized in that, The sum of the axial length of the winding tube (3) and the axial length of the magnetic element (4) of the winding tube (3) is greater than the distance from the base (103) to the electrical contact (5).

5. The overcurrent protection resistor according to claim 4, characterized in that, The magnetic field generated in the winding tube (3) by the resistor coil (2) when a current in a predetermined direction passes through it repels the magnetic poles of the magnetic component (4) near the base (103).

6. The overcurrent protection resistor according to claim 5, characterized in that, When the rated current passes through the resistor coil (2), the force exerted by the coil (2) on the magnetic component (4) in the axial direction away from the base (103) is less than the weight of the magnetic component (4).

7. The overcurrent protection resistor according to claim 6, characterized in that, When the current passing through the resistor coil (2) exceeds the threshold current value, the magnetic field generated by the resistor coil (2) exerts a force on the magnetic component (4) in the axial direction of the winding tube (3) away from the base (103) less than the gravity of the magnetic component (4), wherein the threshold current is greater than the rated current.

8. The overcurrent protection resistor according to claim 2, characterized in that, The first pin (101) and the second pin (102) are disposed on the base (103).

9. The overcurrent protection resistor according to claim 2, characterized in that, The base (103) is provided with a positioning ring groove (106), the shape of which is adapted to the shape of the end of the tube (104) near the base (103), and the end of the tube (104) near the base (103) is embedded in the positioning ring groove (106).

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