SU33227A1 - Method for detecting cable toast break - Google Patents

Description

The present invention relates to a method for detecting a break in a core of a single-core cable without a metal protective sheath in order to reduce the capacitance between the special fixed metal sheath and the core of the test cable that is pulled through the said plate. The cable core and the tube form a capacitor, which is connected to a circuit of an oscillating circuit. When passing through the cable tube to the point of breakage, the capacitance of the capacitor remains constant. With the passage of the break point and further, the capacitance of the capacitor decreases sharply, which can be detected by any of the known methods: L) by including a capacitor in the oscillator circuit; 2) incorporating it into the circuit of one of the two connected local oscillators, using the beat method, etc. X

In FIG. 1 shows a single-core cable with a cross-section, provided with the test plate mentioned above; FIG. 2, 3 and 4 - the corresponding electrical circuits for the proposed method.

The capacitor formed by the core 2 (FIG. 1) of the cable under test and the fixed lining may be connected to the circuit of the oscillating office 7 of the lamp generator or else parallel (264)

but the capacitor 9 tuning the receiving circuit (Fig. 2). With cable position shown in FIG. 1, when the mass of the break 3 is to the right of the plate 4. The capacitance of the capacitor 6 is formed. shegos between vein 2 and facing. remains constant during cable rewinding, and, consequently, the current in the receiving circuit, which is tuned to resonate with the local oscillator with the help of a capacitor 5, Galvanometer -8, shows this current. When the point of breakage passes by the plate, the capacitance of the cutting capacitor b will decrease, and, consequently, the current resonance in the receiving circuit will be upset. The moment the current is reduced in the receiving circuit and the location of the break is determined.

FIG. 3 shows a diagram of a device with two local oscillators and a telephone 8 in the receiving loop. At the beginning of operation, with the help of a variable capacitor, the oscillating circuit of the generator, in parallel with which the capacitor b formed by the cable and the lining is turned on, achieves the equality of the frequencies given by each local oscillator, i.e. the disappearance of sound in the phone, included in the circuit of the receiving circuit with the detectors. . When rewinding the cable when the breakage place passes by the plate. The capacitor b capacity will decrease;

Therefore, the frequency of the generator, to which the cable is adventurous, will increase, and the phone will hear the sound of a frequency equal to the frequency difference between the two generators. The moment of occurrence of sound corresponds to the place of cable break. It is possible to simplify this scheme by using one of the local oscillators as both the local oscillator and the receiver (Fig. 4). Evacuation of the phone in phone 8 is achieved by generating both local oscillators using a capacitor 9, which in this case is connected to the grid circuit of the second local oscillator and parallel to which is connected a capacitor 6, formed by a residential cable and facing 4, but you can turn them on together or separately. chain

figure 1

anode. The location of the cliff is determined as in the previous case.

The plate 4 can be made in the form of a solid or detachable (yes, quick cable refueling) metal tube, inside which the test cable is pulled.

The subject matter of the invention.

A method for detecting a break point in a single core cable without a metallic protective sheath, characterized in that the cut point x is limited by a decrease in capacitance between the fixed metal lining and the movable core of the cable lining.

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