A current transformer secondary short circuit indicating device

Abstract

The present application relates to the technical field of current transformer, in particular to a kind of secondary short-circuit indicating device of current transformer, including indicator housing, annular power supply coil assembly and load resistance respectively arranged in the indicator housing, LED indicating lamp being arranged on the indicator housing, short-circuit conductor being arranged in the inside of the indicator housing and passing through the annular inner hole of the annular power supply coil assembly, the load resistance and LED indicating lamp are connected in parallel on the two coil lead-out ends of the power supply coil assembly, a pair of electrical connection pins are arranged at the two ends of the short-circuit conductor, and the pair of electrical connection pins extend out of the indicator housing. The present application improves the safety and convenience of current transformer use.

Description

Technical Field

[0001] This invention relates to the field of current transformer technology, and more specifically to a secondary short-circuit indicator device for a current transformer. Background Technology

[0002] A current transformer consists of a closed iron core and a coil (induction coil), with the coil wound around the iron core. It is an instrument that uses the principle of electromagnetic induction to convert a large primary current into a small secondary current to achieve current measurement.

[0003] There are many types of current transformers, the typical ones being enclosed current transformers and switchable current transformers. Among them, switchable current transformers can measure current without disconnecting the circuit being measured, making them convenient to use and widely used.

[0004] However, existing current transformers still have the following problems: When using a current transformer, the secondary coil cannot be open-circuited, because an open-circuit secondary coil will cause high voltage, which may damage the secondary equipment and the safety of relevant testing personnel. Therefore, the secondary side of the current transformer must be connected to the equipment first, and then the primary side is installed. This operation is very troublesome and not conducive to the installation of the current transformer.

[0005] To address the aforementioned problem of cumbersome installation of current transformers, a possible improvement is the use of a secondary short-circuit connector. When using the current transformer, the secondary coil is first connected to the secondary short-circuit connector to form a short-circuit loop. After the primary and secondary sides of the current transformer are installed, the secondary short-circuit connector is manually removed. However, this solution has the following drawbacks: First, it's uncertain whether the short-circuit connector correctly connects the secondary coil and whether the connection is secure; otherwise, connection problems could cause safety issues. Second, even if correctly connected, removal is cumbersome, and problems during removal could still cause an open circuit in the secondary coil. Summary of the Invention

[0006] To address the aforementioned problems, this invention proposes a secondary short-circuit indicating device for a current transformer, aiming to improve the safety and convenience of using current transformers. The specific technical solution is as follows:

[0007] A secondary short-circuit indicating device for a current transformer includes an indicator housing, a ring-shaped power supply coil assembly and a load resistor respectively disposed within the indicator housing, an LED indicator light disposed on the indicator housing, and a short-circuit conductor disposed inside the indicator housing and passing through the annular inner hole of the ring-shaped power supply coil assembly. The load resistor and the LED indicator light are connected in parallel to two coil leads of the power supply coil assembly. A pair of electrical connection pins are provided at both ends of the short-circuit conductor, and the pair of electrical connection pins extend outside the indicator housing.

[0008] Preferably, the ring power supply coil assembly, load resistor, and short-circuit conductor are encapsulated in the indicator housing by epoxy resin casting.

[0009] In this invention, the toroidal power supply coil assembly includes a toroidal iron core, a coil frame wrapped around the toroidal iron core, and a power supply coil wound around the coil frame.

[0010] Preferably, the current transformer has a specification of 100 / 5A, the power supply coil has 1000 turns, and the load resistor has a resistance of 1000 ohms.

[0011] The current transformer with specification 100 / 5A has a primary current of 100A and a secondary current of 5A.

[0012] Preferably, the pair of electrical connection pins are located at one end of the indicator housing, and the LED indicator is located at the other end of the indicator housing.

[0013] In this invention, the housing of the current transformer is provided with a pair of electrical connection sockets, and the pair of electrical connection pins are paired and connected to the pair of electrical connection sockets.

[0014] The two ends of the secondary coil inside the current transformer are electrically connected to the pair of electrical connection sockets, and a pair of CT secondary leads are also connected to the pair of electrical connection sockets.

[0015] Preferably, the current transformer is a closed current transformer or an open-close current transformer.

[0016] In this invention, the indicator housing is a plastic housing.

[0017] The method of using this invention is as follows:

[0018] (1) Before installing the current transformer, insert a pair of electrical connection pins of the secondary short-circuit indicator device into a pair of electrical connection holes on the housing of the current transformer.

[0019] (2) When installing the current transformer, first install and connect the primary side. If the primary side is connected correctly, the LED indicator will light up, indicating that the secondary coil is successfully short-circuited. If it does not light up, it indicates that there is a problem with the current transformer or the indicator has not been short-circuited correctly, and it needs to be checked.

[0020] (3) After the secondary coil is successfully short-circuited, connect the secondary equipment. After the secondary equipment is connected, unplug the secondary short-circuit indicator.

[0021] The beneficial effects of this invention are:

[0022] First, the present invention provides a secondary short-circuit indicator for a current transformer, which is equipped with a quick-connect structure. The induced current provided by the ring power supply coil assembly powers the LED indicator, thereby enabling the operator to confirm whether the secondary coil has been successfully short-circuited, thus improving the safety of the current transformer.

[0023] Secondly, the current transformer secondary short-circuit indicator of the present invention has a plug-in structure that is easy to install and remove. The outer shell of the indicator is made of plastic and the inside is potted with epoxy, and it can be plugged and unplugged by hand, which is convenient and quick. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a secondary short-circuit indicator device for a current transformer according to the present invention;

[0025] Figure 2 yes Figure 1 A schematic diagram of the external structure of the secondary short-circuit indicator device in the image;

[0026] Figure 3 yes Figure 1 A three-dimensional structural diagram (the indicator housing on the secondary short-circuit indicator has been removed from the diagram);

[0027] Figure 4 yes Figure 3 A partially enlarged schematic diagram of the part involving the secondary short-circuit indicator device;

[0028] Figure 5 This is a schematic diagram illustrating the working principle of a secondary short-circuit indicator device for a current transformer.

[0029] In the diagram: 1. Current transformer, 2. Secondary short-circuit indicator, 3. Indicator housing, 4. Toroidal power supply coil assembly, 5. Load resistor, 6. LED indicator, 7. Short-circuit conductor, 8. Electrical connection pin, 9. Toroidal core, 10. Coil frame, 11. Power supply coil, 12. Electrical connection socket, 13. CT secondary lead wire. Detailed Implementation

[0030] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0031] Example 1:

[0032] like Figures 1 to 5The illustration shows an embodiment of a current transformer secondary short-circuit indicating device according to the present invention, comprising an indicator housing 3, a ring power supply coil assembly 4 and a load resistor 5 respectively disposed within the indicator housing 3, an LED indicator 6 disposed on the indicator housing 3, and a short-circuit conductor 7 disposed inside the indicator housing 3 and passing through the annular inner hole of the ring power supply coil assembly 4. The load resistor 5 and the LED indicator 6 are connected in parallel to the two coil leads of the power supply coil assembly 4. A pair of electrical connection pins 8 are provided at both ends of the short-circuit conductor 7, and the pair of electrical connection pins 8 extend outside the indicator housing 3.

[0033] Preferably, the ring power supply coil assembly 4, the load resistor 5, and the short-circuit conductor 7 are encapsulated in the indicator housing 3 by epoxy resin casting.

[0034] In this embodiment, the annular power supply coil assembly 4 includes an annular iron core 9, a coil frame 10 sleeved on the annular iron core 9, and a power supply coil 11 wound on the coil frame 10.

[0035] Preferably, the current transformer 1 has a specification of 100 / 5A, the power supply coil 11 has 1000 turns, and the load resistor 5 has a resistance of 1000 ohms.

[0036] The current transformer 1 with specifications of 100 / 5A has a primary current of 100A and a secondary current of 5A.

[0037] Preferably, the pair of electrical connection pins 8 are located at one end of the indicator housing 3, and the LED indicator 6 is located at the other end of the indicator housing 3.

[0038] In this embodiment, the outer casing of the current transformer 1 is provided with a pair of electrical connection sockets 12, and the pair of electrical connection pins 8 are paired and connected to the pair of electrical connection sockets 12.

[0039] The two ends of the secondary coil inside the current transformer 1 are electrically connected to the pair of electrical connection sockets 12, and a pair of CT secondary lead wires 13 are also connected to the pair of electrical connection sockets 12.

[0040] Preferably, the current transformer 1 is a closed current transformer or an open-close current transformer.

[0041] In this embodiment, the indicator housing 3 is a plastic housing.

[0042] The usage method of this embodiment is as follows:

[0043] (1) Before installing the current transformer 1, the pair of electrical connection pins 8 of the secondary short circuit indicator 2 are connected to the pair of electrical connection holes 12 on the housing of the current transformer 1.

[0044] (2) When installing current transformer 1, first install and connect the primary side. If the primary side is connected correctly, the LED indicator 6 will light up, indicating that the secondary coil is successfully short-circuited. If it does not light up, it indicates that there is a problem with current transformer 1 or the indicator has not been short-circuited correctly, and it needs to be checked.

[0045] (3) After the secondary side coil is successfully short-circuited, connect the secondary side equipment. After the secondary side equipment is connected, unplug the secondary short-circuit indicator 2.

[0046] Example 2:

[0047] The transformer specifications are 100 / 5A (primary current 100A, secondary current 5A), and a secondary short-circuit indicator is designed.

[0048] Because a current of 5A can provide a current of 5A to the secondary short-circuit device; the power supply coil of the short-circuit device uses a high-permeability silicon steel core, 13*18*5, and uses copper wire with a diameter of 0.11, wound with 1000T (turns).

[0049] Therefore, the power supply coil can output a current of 5A / 1000T = 0.005A.

[0050] Using a 1K load resistor, an AC voltage of approximately 5V can be output, which is sufficient to drive 3-5V LEDs.

[0051] The power supply coil output is AC, while the LED indicator is theoretically DC input. However, AC can drive it. Since only half-wave can drive the LED indicator, the brightness is slightly lower than that of DC, but it does not affect the human eye's judgment.

[0052] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A secondary short-circuit indicating device for a current transformer, characterized in that, The device includes an indicator housing, a ring-shaped power supply coil assembly and a load resistor respectively disposed within the indicator housing, an LED indicator light disposed on the indicator housing, and a short-circuit conductor disposed inside the indicator housing and passing through the annular inner hole of the ring-shaped power supply coil assembly. The load resistor and the LED indicator light are connected in parallel to two coil leads of the power supply coil assembly. A pair of electrical connection pins are provided at both ends of the short-circuit conductor, extending beyond the indicator housing. The current in the ring-shaped power supply coil assembly is obtained through electromagnetic induction using the secondary current flowing through it after a successful short circuit of the secondary coil. The method for achieving a short circuit of the secondary coil during the installation of the current transformer includes the following: The following steps should be followed for installing current transformers and confirming short circuits in the secondary winding: (1) Before installing the current transformer, insert a pair of electrical connection pins of the secondary short-circuit indicator device into a pair of electrical connection sockets on the housing of the current transformer. (2) When installing the current transformer, first install and connect the primary side. If the primary side is connected correctly, the LED indicator will light up, indicating that the secondary coil is successfully short-circuited; if it does not light up, it indicates that there is a problem with the current transformer or the indicator has not been short-circuited correctly, and it needs to be checked. (3) After the secondary coil is successfully short-circuited, connect the secondary equipment. After the secondary equipment is connected, unplug the secondary short-circuit indicator.

2. The current transformer secondary short-circuit indicating device according to claim 1, characterized in that, The ring power supply coil assembly, load resistor, and short-circuit conductor are encapsulated in the indicator housing by epoxy resin casting.

3. The current transformer secondary short-circuit indicating device according to claim 1, characterized in that, The toroidal power supply coil assembly includes a toroidal iron core, a coil frame wrapped around the toroidal iron core, and a power supply coil wound around the coil frame.

4. A current transformer secondary short-circuit indicating device according to claim 3, characterized in that, The current transformer has a specification of 100 / 5A, the power supply coil has 1000 turns, and the load resistor has a resistance of 1000 ohms.

5. A current transformer secondary short-circuit indicating device according to claim 1, characterized in that, The pair of electrical connection pins are located at one end of the indicator housing, and the LED indicator is located at the other end of the indicator housing.

6. A current transformer secondary short-circuit indicating device according to claim 1, characterized in that, The housing of the current transformer is provided with a pair of electrical connection sockets, and the pair of electrical connection pins are paired and connected to the pair of electrical connection sockets.

7. A current transformer secondary short-circuit indicating device according to claim 6, characterized in that, The two ends of the secondary coil inside the current transformer are electrically connected to the pair of electrical connection sockets, and a pair of CT secondary leads are also connected to the pair of electrical connection sockets.

8. A current transformer secondary short-circuit indicating device according to claim 1, characterized in that, The current transformer is either a closed-type current transformer or an open-type current transformer.

9. A current transformer secondary short-circuit indicating device according to claim 1, characterized in that, The indicator housing is made of plastic.

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