Multifunctional short-circuit protection circuit

Abstract

The utility model relates to the technical field of protection circuits, in particular to a multifunctional short-circuit protection circuit, which comprises a fuse F, an NTC (Negative Temperature Coefficient) thermistor R1, a PTC (Positive Temperature Coefficient) thermistor R2, a halogen lamp L and an audible and visual alarm BZ, the head end of a series branch formed by connecting the fuse F and the NTC thermistor R1 in series is used as a terminal A, the tail end of the series branch formed by connecting the fuse F and the NTC thermistor R1 in series is connected with the head end of the PTC thermistor R2, and the tail end of the PTC thermistor R2 is used as a terminal B; the problems that when an existing fuse is used, replacement is needed once the fuse is fused, time and labor are consumed, even production interruption is caused, particularly when intermittent short-circuit faults occur, the fuse is burnt out irregularly, maintenance difficulty is increased, efficiency is low and processing time is long due to repeated power transmission and fault point searching, and large-current impact can damage line contacts, so that the service life of the fuse is prolonged are solved. Aging is accelerated, and greater potential safety hazards are caused.

Description

Technical Field

[0001] The utility model relates to the technical field of protection circuits, and particularly relates to a multifunctional short - circuit protection circuit. Background Technique

[0002] In the field of modern industrial control technology, fuses are widely used as basic over - load and short - circuit protection devices. Traditional fuses are mainly composed of metal wires or metal sheets. Their working principle is that when the current exceeds a predetermined value, they melt due to self - heating, thus cutting off the circuit to prevent equipment from being damaged by over - current.

[0003] However, the existing fuses still have many limitations in use. First of all, traditional fuses can only provide one - time protection in case of over - load or short - circuit. Once they melt, they need to be replaced manually, which is not only time - consuming and laborious, but also may lead to production interruption. Especially in the case of intermittent short - circuit faults, the fuses will be burned out irregularly, which not only increases the difficulty of maintenance, but also may lead to repeated power - on during the process of finding the fault point, with low maintenance efficiency, long fault - handling time. At the same time, continuous large - current impacts will not only burn out the fuses, but also damage the joints of the circuit, accelerate their aging, and thus cause greater potential safety hazards.

[0004] Therefore, it is necessary to invent a multifunctional short - circuit protection circuit to solve the above problems. Content of the Utility Model

[0005] The utility model provides a multifunctional short - circuit protection circuit to solve the problems existing in the use of existing fuses, that is, once they melt, they need to be replaced, resulting in time - consuming and laborious work or even production interruption. Especially in the face of intermittent short - circuit faults, the fuses are burned out irregularly, increasing the difficulty of maintenance. Repeated power - on to find the fault point leads to low efficiency and long processing time, and large - current impacts will damage the circuit joints, accelerate aging, and cause greater potential safety hazards.

[0006] The utility model is realized by adopting the following technical scheme:

[0007] A multifunctional short - circuit protection circuit includes a fuse F, an NTC thermistor R1, a PTC thermistor R2, a halogen lamp L, and an audible and visual alarm BZ. The head end of the series branch formed by connecting the fuse F and the NTC thermistor R1 in series is used as the terminal A. The tail end of the series branch formed by connecting the fuse F and the NTC thermistor R1 in series is connected to the head end of the PTC thermistor R2. The tail end of the PTC thermistor R2 is used as the terminal B. The two ends of the halogen lamp L are respectively connected to the two ends of the PTC thermistor R2. The two ends of the audible and visual alarm BZ are respectively connected to the two ends of the PTC thermistor R2.

[0008] Further, the rated current of the fuse F is 1.5A.

[0009] The structure design of the utility model is reasonable and reliable. Through the automatic recovery function of the PTC thermistor, the problem that the traditional fuse needs to be replaced after melting is solved, and production interruption is avoided. Through the instant alarm function of the sound and light alarm, the fault can be quickly prompted when a short circuit occurs, which is convenient for technicians to find the fault point and improve the maintenance efficiency. At the same time, combined with the auxiliary indication of the halogen lamp L, the fault state can be further confirmed. Through the automatic recovery function and the instant sound and light alarm function, the situation that the traditional fuse needs to repeatedly power on to find the fault point is avoided, and the fault handling time is shortened. By limiting the current in the high-resistance state of the PTC thermistor, the line joints are effectively protected from the impact of large current, the line aging is reduced, and greater potential safety hazards are avoided, thus realizing multiple protections for the circuit and improving the safety and reliability of the overall circuit. Description of the Drawings

[0010] Figure 1 is the circuit diagram of the utility model. Detailed Embodiments

[0011] A multifunctional short-circuit protection circuit includes a fuse F, an NTC thermistor R1, a PTC thermistor R2, a halogen lamp L, and a sound and light alarm BZ. The head end of the series branch formed by connecting the fuse F and the NTC thermistor R1 in series is used as the terminal A, the tail end of the series branch formed by connecting the fuse F and the NTC thermistor R1 in series is connected to the head end of the PTC thermistor R2, the tail end of the PTC thermistor R2 is used as the terminal B, both ends of the halogen lamp L are respectively connected to both ends of the PTC thermistor R2, and both ends of the sound and light alarm BZ are respectively connected to both ends of the PTC thermistor R2.

[0012] The rated current of the fuse F is 1.5A.

[0013] When there is an intermittent short circuit in the target circuit or it is necessary to detect the short-circuit fault point, this multifunctional short-circuit protection circuit is used to replace the original fuse and connected in series to the target circuit. The terminal A is connected to the power supply, and the terminal B is connected to the load.

[0014] Under normal working conditions, the PTC thermistor R2 maintains a low-resistance state, the circuit current is stable, the halogen lamp L is extinguished, and the sound and light alarm BZ does not work.

[0015] When overcurrent or short circuit occurs, the PTC thermistor R2 quickly heats up and enters a high-resistance state, restricting the current flow and protecting the safety of the target circuit. At this time, the halogen lamp L lights up, and the sound and light alarm BZ starts to emit an alarm signal, which is convenient for quickly locating the fault point and improving the maintenance efficiency.

[0016] When the short - circuit fault is eliminated, the PTC thermistor R2 automatically returns to the low - resistance state, and the target circuit resumes normal operation. At this time, the halogen lamp L goes out, and the sound - light alarm BZ stops alarming. There is no need for manual fuse replacement, reducing the downtime and maintenance costs.

[0017] PTC thermistors are often used in over - voltage, over - current, overload protection, etc. When performing the protection function, the heat generated causes the polymer organic polymer to expand, and the conductive particles wrapped in the polymer organic polymer will separate, thus cutting off the conductive path of the PTC thermistor, increasing the resistance of the PTC thermistor, and reducing the abnormal over - current. When the abnormal over - current fault is cleared, the polymer organic polymer of the PTC thermistor shrinks to its original shape and reconnects the conductive particles, the conductive path is restored, and the resistance of the PTC thermistor will return to its original low - resistance state.

[0018] The NTC thermistor R1 plays two roles in the target circuit. One is to limit the instantaneous surge current when the target circuit is initially powered on, protecting the target circuit from impact damage. The other is to provide a certain reaction time for the PTC thermistor R2 in case of a short - circuit.

[0019] In the specific implementation process, the PTC thermistor R2 is connected in parallel across the two ends of the bulb and attached to the halogen lamp L. In case of a short - circuit, the PTC thermistor R2 will heat up and enter the high - resistance state. At the same time, the halogen lamp L heats up faster, increasing the temperature, so that the PTC thermistor R2 quickly increases its resistance value to protect the circuit.

[0020] Through the above - mentioned usage process, this multifunctional short - circuit protection circuit can not only solve the problem of replacing the traditional fuse after it melts through the automatic recovery function, avoiding production interruption; but also, through the instant alarm function of the sound - light alarm, quickly prompt the fault when a short - circuit occurs, facilitating technicians to find the fault point and improving the maintenance efficiency. At the same time, combined with the auxiliary indication of the halogen lamp L, the fault state can be further confirmed; through the automatic recovery function and the instant sound - light alarm function, it avoids the situation where the traditional fuse needs to be repeatedly powered on to find the fault point, shortening the fault handling time; by limiting the current in the high - resistance state of the PTC thermistor, it effectively protects the circuit joints from the impact of large currents, reduces circuit aging, and avoids greater potential safety hazards, thus achieving multiple protections for the circuit and improving the safety and reliability of the overall circuit.

[0021] In the description of the present utility model, it should be understood that the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present utility model.

[0022] Although embodiments of the present utility model have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principle and spirit of the present utility model. The scope of the present utility model is defined by the appended claims and their equivalents.

Claims

1. A multifunctional short-circuit protection circuit, characterized in that: It includes a fuse F, an NTC thermistor R1, a PTC thermistor R2, a halogen lamp L, and an audible and visual alarm BZ; the head end of the series branch formed by connecting the fuse F and the NTC thermistor R1 in series is used as the terminal A, the tail end of the series branch formed by connecting the fuse F and the NTC thermistor R1 in series is connected to the head end of the PTC thermistor R2, the tail end of the PTC thermistor R2 is used as the terminal B, both ends of the halogen lamp L are respectively connected to both ends of the PTC thermistor R2, and both ends of the audible and visual alarm BZ are respectively connected to both ends of the PTC thermistor R2.

2. The multifunctional short-circuit protection circuit according to claim 1, characterized in that: The rated current of the fuse F is 1.5 A.

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