NOYAFA Electronic specializing in testing instruments and cable testers for 16 years
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NOYAFA Electronic specializing in testing instruments and cable testers for 16 years
Author: Noyafa–Cable Length Tester
The cable routing instrument is mainly composed of signal transmitter and receiver. Before using the instrument, electric power workers need to understand its main working principle, so as to give full play to the function of the instrument, quickly find the fault point of the cable, and eliminate the fault as soon as possible to ensure that the cable path instrument is mainly composed of signal transmitter and receiver. . Before using the instrument, electric power workers need to understand its main working principle, so as to give full play to the function of the instrument, quickly find the fault point of the cable, and eliminate the fault as soon as possible to ensure the power supply.
Next, the editor will take you to an in-depth understanding of the working principle of the cable path meter. The cable path meter is a high-tech product designed based on the reflection principle and electromagnetic induction principle of electromagnetic waves in the transmission process, combined with digital filtering, wireless reception, and software control. The basic working principle of electromagnetic induction is that the transmitter generates electric and magnetic waves and transmits the transmitted signal to the underground metal pipeline to be detected through different transmission connection methods. After the metal pipeline senses the electromagnetic wave, an induced current is generated on the surface of the cable, and the induced current is It will propagate to the distance along the metal cable. During the propagation of the current, electromagnetic waves will be radiated to the ground through the cable, so that when the receiver of the underground metal pipeline tester detects on the ground, it will The ground directly above the pipeline receives the electromagnetic wave signal, and the position and direction of the underground metal pipeline can be judged by the change of the strength of the received signal.
The conditions for the realization of this principle: First, there must be a signal source that can emit enough electrical energy to form a current in the line capable of transmitting electrical energy, and the current will generate a magnetic field around the line during the flow; secondly, it must be able to receive this specific The circuit of the magnetic field displays the changing process of the magnetic field in the form of electrical signals. Instrument transmitter working mode: The transmitter has four working modes (direct connection method, clamp coupling method, induction method and loop resistance measurement). To ensure the reliable transmission of the signal on the target metal pipeline, there must be a reliable loop in the line. It can be an indirect loop composed of the ground, a capacitive loop composed of a distributed capacitance formed between a sufficiently long metal pipeline and the ground, or a direct loop composed of short-circuit fault points between lines.
Different circuits satisfy different tests. The signal of the transmitter is directly applied to the target metal pipeline (power failure metal pipeline) with a direct connection line, that is, the direct connection method. The direct connection line is divided into red and black lines. The red line is connected to a certain line of the metal pipeline. The black line is the working ground wire of the instrument, which should be separately and reliably grounded.
In order to ensure one-way reliable transmission of signals in the line, it is required to disconnect at least one end of the ground wire of the target metal pipeline, so that the signal can return through the ground in the form of an indirect loop or a capacitive loop. Receiver working mode: When the signal is applied to the metal pipeline, there will be current on the metal pipeline, and at the same time, the current will generate a magnetic field to radiate around the metal pipeline. The frequency of the magnetic field is consistent with the frequency of the applied signal. The strength is the metal pipeline as the center of the circle and the radiation is decreased, and the direction is the tangent direction of a certain point on the radiation circle.
The receiver receives the magnetic field signal or the leaked electric field signal radiated by the metal pipeline through the internal antenna, and can be processed by five different frequency working modes, and the signal strength change is prompted to the operator. The above is the editor's in-depth analysis and introduction of the cable routing instrument, I hope it can be helpful to everyone.
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