JPH03201313A - Structure for detecting abnormal heat generation from electric cable - Google Patents

Abstract

PURPOSE:To enable the detection and display of the abnormal heat generation from an electric cable, by deforming a display body of shape memory alloy by the surface temperature of the electric cable shield, releasing the display body from covering the shield, displaying the abnormal heat generation and holding the display body in the vicinity of the cable with a holding means. CONSTITUTION:A display body 1 of shape memory alloy is deformed, as if a plate material wrapped the shield Wa of an electric cable W, and fixed in contact with the shield Wa while the memorized shape in high temperature phase is turned into an arc shape of a large radius of curvature and restored into the original memorized shape at high temperature over the determined, which transformational displacement follows the display body 1. A holding means 2 is provided to hold the display body 1 in place on the electric cable W and composed of a fixture 3 to be fixed on the shield Wa and flexible wire body 4 to connect mechanically the fixture 3 to the display body 1. In this method, the display body 1 can be installed in a suitable place for detecting and checking the abnormal heat generation from the electric cable W.

Description

Detailed Description of the Invention "Field of Industrial Application" The present invention relates to a structure for detecting abnormal heat generation in electric cables, and in particular, to detect abnormal heat generation in electric cables such as insulated wires and power cables having insulation coatings. and markings.

``Prior Art'' Electrical cables coated with insulation have a permissible temperature set depending on the type of electrical insulation material, and are used within that range.

When it is necessary to measure the temperature of such an electric cable, a method is adopted in which the temperature is measured by applying an appropriate thermometer or a temperature sensor of a temperature measuring instrument to the surface of the outer sheath of the electric cable.

"Problems to be Solved by the Invention" However, since the current of an electric cable varies greatly depending on the load condition, the surface temperature of the jacket (
Cable temperature) is rarely at its highest temperature,
Even if there had been an abnormal exothermic temperature that exceeded the allowable temperature in the past, there was no way to confirm this. In other words, there is a technical problem in that it is difficult to retroactively investigate whether abnormal heat generation or overheating exceeding the allowable temperature has occurred in the electric cable.

The present invention has been made in view of the above-mentioned circumstances. (1) Detecting and indicating when an abnormal temperature rise occurs in an electric cable.

■It should be possible to easily check whether there is a history of abnormal heat generation after some time has elapsed.

■The structure for detection and indication is simple and can be used repeatedly.

The purpose is to

``Means to solve problems'' We propose three methods to solve these problems.

The first means is to coat the surface of the outer sheath of the electric cable so as to enclose the outer sheath, and restore the memorized shape to the memorized shape by heat generated when the electric cable abnormally generates heat, and then cover the surface of the outer sheath. a sign made of a shape memory alloy that deforms so as to release the covering state; and a holding means attached to the outer cover and holding the indicator on the surface of the outer cover when the cover state is released. This is a structure for detecting abnormal heat generation in electric cables.

The second means is to prevent abnormal heat generation of the electric cable, in which the holding means in the first means is composed of a fitting attached to the outer sheath and a flexible filament connecting the fitting and the sign body. It is a sensing structure.

The third means is such that the holding means includes an attachment that is attached to the outer cover, and a resilient member that connects the attachment and the indicator and urges the indicator in a direction away from the surface of the outer cover. This is a structure for detecting abnormal heat generation in electric cables.

"Function" In the abnormal heat generation detection structure of the electric cable according to the first means, when the temperature of the electric cable becomes high and the surface temperature of the outer sheath reaches the transformation temperature or higher of the shape memory alloy, the heated sign body It undergoes deformation to restore the memorized shape, releases the sheathing state on the outer sheath, and provides an indication that abnormal heat generation has occurred in the electric cable. By retaining this indicator at a position near the cable by the holding means, it clearly indicates that the electric cable has generated abnormal heat, and this can be easily confirmed at any time by viewing the cable. It is something.

In the abnormal heat generation detection structure for an electric cable according to the second means, since the holding means is made of a flexible filament,
The indicator whose covering on the outer sheath has been released is held in a state where it hangs down from the electric cable, thereby clearly indicating that abnormal heat generation has occurred.

In the abnormal heat generation detection structure of the electric cable according to the third means, since the holding means is made of a resilient member, the indicator body which has been deformed into the memorized shape and released from the sheathing state on the outer sheath can be attached to any part of the outer circumference of the cable. It becomes possible to separate them in the direction of . In other words, by selectively determining the setting position of the resilient member in the direction of the outer circumference of the cable, it is possible to move the indicator away from the outer circumference of the cable in any direction such as upward, downward, leftward, rightward, etc. Therefore, it is possible to make settings that are easy to check depending on the location of the sign.

``Example'' Hereinafter, an abnormal heat generation detection structure for an electric cable according to the present invention will be described with reference to drawings showing examples.

Fig. 1 (AXB) shows the case where the present invention is applied to an electric cable (insulated cable) W laid horizontally, where Wa is the jacket, wb is the conductor, and 1 is the indicator. , 2 is a holding means.

As shown by solid lines in FIGS. 1(A) and 1(B), the sign 1 is
The plate-like material is deformed so as to wrap around the jacket Wa of the electric cable W, and is covered in contact with the jacket Wa, while the memorized shape in the high temperature phase has a curvature shown by the dashed-dotted line in FIG. 1(B). It is shaped like an arc with a large radius, and when the temperature exceeds the set temperature,
It is said to involve displacement such as metamorphosis that restores the memory shape.

The holding means 2 maintains the positional relationship of the sign 1 with respect to the electric cable W, and includes a fitting 3 for attaching to the outer sheath Wa, and a fitting 3 and the sign 1.
and a flexible filament 4 for mechanically connecting the two.

The attachment tool 3 includes a clamp member 3a that is wrapped around the outer periphery of the outer sheath Wa, and a fastening member 3b for fixing the clamp member 3a to the outer sheath Wa.
The flexible filament 4 may be a braided wire, a chain, a string, or the like.

The abnormal heat generation detection structure having such a configuration is used by attaching the holding means 2 to the electric cable W and covering the lower part of the electric cable W with the indicator l in the jacket Wa.

When abnormal heat generation occurs in the electric cable W, its surface temperature rises and the indicator l is heated, and when the temperature of the indicator l reaches the transformation temperature or higher, the indicator l becomes a high-temperature phase of the shape memory alloy. It instantaneously transforms into a memorized shape, and in other words, as shown from the solid line to the dashed-dotted line in FIGS. be done.

When the sign 1 is in the above state, the sign 1 tries to fall due to its own weight, but the fall is prevented by the presence of the flexible filament 4, and as shown in FIGS. 1(A) and 1(B). At this time, as shown by the two-dot chain line, the electric cable W is suspended from the fixture 3, thereby indicating that abnormal heat generation has occurred in the electric cable W. In this case, since the sign l is maintained in its hanging state, it can be confirmed at any time that abnormal heat generation has occurred in the electric cable W. Note that repeated use is possible by covering the electric cable W again with the indicator l so as to wrap the lower part of the outer sheath Wa.

Next, FIGS. 2 and 3 show two other embodiments of the abnormal heat generation detection structure, and in the example in FIG. The holding means 2 connects the above-mentioned attachment 3 and the indicator 1 and urges the indicator 1 away from the outer sheath Wa of the electric cable W. The example in FIG.
The holding means 2 is made up of a fitting 3 and a connecting member 6 that connects the fitting 3 and the sign 1 and prevents deformation between them.

When the electric cable W generates heat and the temperature of the indicator 1 reaches the transformation temperature or higher, as shown by the chain lines in FIGS. 2(A)(B) and 3(A)(B), The sign body l is opened and the cover Wa is released, and in the example shown in FIG.
As shown by the dotted chain line, the sign body 1 is held in an upwardly sprung state, and in the example in FIG. and indicates that abnormal heat generation has occurred in the electric cable W.

On the other hand, Figure 4 shows the electric cable (insulated cable) W.
An example in which the present invention is implemented in a rising portion 8 of a cable head 7 is shown.

Regarding the abnormal heat generation detection structure of each embodiment, the example shown in FIG. 1 to the example shown in FIG. 3 are used depending on the installation direction of the electric cable W and the ease of inspection.

"Effects of the Invention" According to the abnormal heat generation detection structure for an electric cable according to the present invention, since the indicator made of a shape memory alloy is coated so as to be in contact with the surface of the outer sheath of the electric cable, the abnormal heat generation detection structure of the electric cable is detected. When heat is generated, the sign instantly transforms into the memorized shape of the high-temperature phase of the shape memory alloy using this heat as a heat source, and releases the sheathing state from the outer jacket. It is possible to reliably confirm that abnormal heat generation has occurred.

Moreover, since the indicator is held in the vicinity of the outer cover by the holding means, it is possible to easily confirm at any time later that abnormal heat generation has occurred in the electric cable.

Furthermore, since the heat generated by the electric cable is used to heat the sign, no special energy source is required for the sign, and the structure is simple, so it can be easily installed on existing lines. It is easy to apply, and the sign can be used repeatedly.

Furthermore, there is a structure in which a fitting attached to the outer cover and a sign body are connected by a resilient member,
The direction of separation of the sign body from the outer sheath, which transforms into a memorized shape and releases the covering state from the outer sheath, can be set in any direction such as the direction along the cable, downward, leftward, rightward, etc., regardless of the direction of gravity. Since the direction can be determined, the indicator can be set in a suitable posture position for inspecting and confirming the occurrence of abnormal heat generation in the electric cable.

Effects such as this can be obtained.

[Brief explanation of drawings]

FIG. 1(A) is a front view showing an embodiment of the abnormal heat generation detection structure for an electric cable according to the present invention, FIG. 1(B) is a view taken along the line IB-IB in FIG. 1(A), and FIG. Figure 2 (A) and 3rd
Figure (A) is a front view showing other embodiments of the present invention, and Figures 2 (B) and 3 (B) are
The HE-JIB line arrow view and the IITB111B line arrow view in FIGS. be. W...Electric cable, Wa...Sheath, wb...Conductor, l...Indicator, 2...Holding means, 3... ... Attachment tool, 3a ... Clamp member, 3b ... Fastening member, 4 ... Flexible filament, 5 ... Resilient member, 6 ... ... Connecting member, 7 ... Cable head, 8 ... Standing part. Figure 4

Claims (1)

[Claims] 1. The surface of the jacket (Wa) of the electric cable (W) is coated so as to enclose the jacket (Wa), and the electric cable (W) is coated with heat generated when the electric cable (W) generates abnormal heat. A sign body (1) made of a shape memory alloy that is deformed so as to restore to a memorized shape and release the coating state on the surface of the outer sheath (Wa), and the outer sheath (Wa).
Wa) and the marking body (1)
An abnormal heat generation detection structure for an electric cable, characterized in that it has a holding means (2) for holding the surface of the outer sheath (Wa) when the sheathing state is released. 2. The holding means (2) includes a fitting (3) attached to the outer jacket (Wa), and the fitting (3) and the sign (1).
2. The abnormal heat generation detection structure for an electric cable according to claim 1, characterized in that the structure comprises a flexible filament (4) connecting the wires. 3. The holding means (2) includes a fitting (3) attached to the outer cover (Wa), and the fitting (3) and the sign (1).
) and a resilient member (5) that urges the indicator (1) in a direction away from the surface of the outer sheath (Wa). Heat generation detection structure.