JP7675602B2 - Tracking Detection Structure - Google Patents

Description

The present invention relates to a tracking detection structure for detecting tracking discharges that occur at electrical circuit connections such as outlets and connectors.

Tracking discharges may occur in electrical circuit connections such as outlets and connectors, and there are outlets and other devices that have been designed to prevent this.
For example, in the outlet of Patent Document 1, a hole for detecting tracking discharge is provided between the receiving blades on the front surface of the outlet case, and a sensor for detecting tracking discharge is placed inside the hole. A tracking discharge determination circuit is connected to the sensor to determine whether or not tracking discharge occurs.

JP 2007-57524 A

The configuration in which a sensor is placed inside the hole to detect tracking discharge has the problem that the sensor is placed in the hole but has a structure in which the tip is exposed, and therefore can malfunction due to the adhesion of dust or static electricity.
Furthermore, in cases where a housing such as an electrical outlet is provided, holes can be easily formed, making it easy to form a tracking structure; however, in the case of an electrical circuit formed on a plate-like component such as a substrate, it is difficult to adopt a conventional tracking detection structure.

In view of these problems, the present invention aims to provide a tracking detection structure that can detect tracking discharges while reducing malfunctions and that can detect tracking discharges with a simple structure even if the member is a plate-like member.

In order to solve the above problems, the invention of claim 1 is a tracking detection structure for detecting tracking discharges generated at an electrical circuit connection, which is characterized in that a sensor conductor for detecting a current generated by a tracking discharge is disposed between the electrodes of the electrical circuit connection at a location where a tracking discharge may occur, and the detection portion of the sensor conductor is covered with a film-like insulator that is carbonized or scattered by the generated tracking discharge.
With this configuration, the film-like insulator is carbonized or scattered by the heat of the generated tracking discharge. As a result, the discharge current of the tracking discharge eventually flows into the sensor conductor, making it possible to detect the occurrence of the tracking discharge. Therefore, it is possible to detect the tracking discharge with a simple configuration in which the sensor conductor is disposed between the electrodes.
In addition, since the sensor conductor is covered with the film-like insulator under normal conditions, current will not flow into the sensor conductor due to adhesion of dust or static electricity, and malfunction can be prevented.

The invention of claim 2 is characterized in that, in the configuration described in claim 1, the sensor conductor is inside a housing made of synthetic resin having a pair of connection terminals that constitute an electrical circuit connection portion, and is arranged with its tip facing outward between the electrodes of the connection terminals, and the electrode space of the housing where the tip of the sensor conductor is arranged is formed into a thin film-like shape.
According to this configuration, the sensor conductor is disposed inside the housing, and when the housing is carbonized by the tracking discharge, the current of the tracking discharge flows into the sensor conductor, making it possible to detect the tracking discharge.

The invention of claim 3 is characterized in that, in the configuration described in claim 1, a pair of exposed electrical paths for connecting a connector to which an electric wire is connected are patterned on the printed circuit board as an electrical path connection portion, and the sensor conductor is patterned between the pair of exposed electrical paths, and its upper portion is covered with a resist.
According to this configuration, the sensor conductor is covered with a resist, but the resist is scattered by the tracking discharge, causing a current of the tracking discharge to flow into the sensor conductor, making it possible to detect the tracking discharge.

According to the present invention, the film-like insulator is carbonized or scattered by the heat of the generated tracking discharge. As a result, the discharge current eventually flows into the sensor conductor, making it possible to detect the occurrence of the tracking discharge. Therefore, it is possible to detect the tracking discharge with a simple configuration in which the sensor conductor is disposed between the electrodes.
In addition, since the sensor conductor is covered with the film-like insulator under normal conditions, current will not flow into the sensor conductor due to adhesion of dust or static electricity, and malfunction can be prevented.

FIG. 2 shows an example of a tracking detection structure according to the present invention, illustrating a portion where a connector is connected to a substrate. In the tracking detection structure of FIG. 1, (a) shows an initial state in which a tracking discharge occurs, and (b) shows a state in which the tracking discharge has progressed and the substrate has deteriorated, causing the tracking discharge to be detected. 1A and 1B are explanatory diagrams showing a tracking detection structure provided in an outlet, in which (a) is a partially enlarged external view, and (b) is a cross-sectional view taken along line AA, showing the portion where the sensor conductor is provided. 1A and 1B are explanatory diagrams showing a tracking detection structure provided in a circuit breaker, in which (a) is a partially enlarged external view, and (b) is a cross-sectional explanatory diagram showing the portion where a sensor conductor is provided, taken along line B-B.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings, in which: FIG. 1 shows an example of a tracking detection structure according to the present invention, and is an explanatory diagram of a portion where a connector is connected to a printed circuit board (substrate).
In Fig. 1, reference numeral 1 denotes a substrate, 2 denotes a connector for connecting a power line L, 3 denotes an exposed electric circuit as an electric circuit connection portion patterned on substrate 1 for connecting connector 2, and 4 denotes a sensor conductor similarly patterned between exposed electric circuits 3. Terminal 2a of connector 2 is soldered to exposed electric circuit 3 on substrate 1 for connection. Reference numeral 5 denotes a soldering site.

The exposed electric path 3 formed on the substrate 1 has the connection portion of the connector 2 exposed, but the sensor conductor 4 is coated with a resist 6 which is an insulator, and is covered and protected by the film of the resist 6.
1 etc., the resist 6 is shown by hatching. The sensor conductor 4 is connected at its end to a tracking detection section (not shown), and is configured to detect the tracking discharge current flowing into the sensor conductor 4 and perform an alarm operation or the like.

Fig. 2 shows a state in which a tracking discharge has occurred on the substrate 1 thus formed. Fig. 2(a) shows the initial state, and Fig. 2(b) shows a state in which the tracking discharge has progressed, the substrate 1 has deteriorated, and a tracking discharge current flows through the sensor conductor 4. In Fig. 2, an arrow S indicates a tracking discharge. A tracking discharge occurs between the terminals 2a, which are between the electrodes, but because the soldered portions 5 are closest to each other, tracking discharge often occurs between the soldered portions, as shown in Fig. 2, even between exposed electric circuits 3.
It is known that tracking discharge occurs when moisture adheres to dust or dirt on the substrate 1, causing a decrease in insulation resistance between the electrodes.

After this tracking discharge occurs several times, the resist 6 covering the surface eventually scatters, exposing the sensor conductor 4. Figure 2(b) shows this state, with P indicating the area where the resist has scattered. When this happens, the generated tracking discharge P flows into the sensor conductor 4 as indicated by the arrow T, and the occurrence of the tracking discharge is detected by the tracking detection unit connected to the sensor conductor 4. However, while Figure 2(b) shows a state in which a discharge current flows from one specific terminal 2a to the sensor conductor 4, a discharge current also flows between the other terminal 2a and the sensor conductor 4 that forms a pair due to the polarity.

In this way, when the resist, which is a film-like insulator, is scattered by the heat of the generated tracking discharge, the current of the tracking discharge eventually flows into the sensor conductor 4. As a result, the occurrence of the tracking discharge is detected. Therefore, it is possible to detect the tracking discharge with a simple configuration in which the sensor conductor 4 is disposed between the terminals 2a, which are between the electrodes.
In addition, since the sensor conductor 4 is covered with the resist 6 under normal conditions, no current will flow into the sensor conductor 4 due to adhesion of dust or static electricity, thereby preventing malfunction. In addition, since the sensor conductor 4 is patterned on the substrate 1, there is no need to assemble the sensor conductor separately on the substrate.

In addition, a silicon coating may be provided on top of the resist 6 to make it more durable, and this will be scattered by tracking discharge and eventually become exposed.

Figure 3 shows another form of tracking detection structure, and is an explanatory diagram of an outlet that is provided with the structure. Figure 3(a) is an external view of the outlet with a part enlarged, and Figure 3(b) is an explanatory diagram of a cross section taken along line A-A, showing a vertical cross section of the middle part M1 of the outlet hole. In Figure 3, 11 is the housing of the outlet 10, 12 is the outlet hole for connecting a plug, and 13 is the sensor conductor. Inside the outlet hole 12, a receiving blade (not shown) is arranged for electrical connection with an inserted plug, and the outlet hole 12 constitutes the electrical circuit connection part.

As shown in FIG. 3(a), the sensor conductor 13 is not visible from the outside, but as shown in FIG. 3(b), the sensor conductor 13 is disposed in the intermediate portion M1 between the outlet holes 12 provided on the left and right. Specifically, the sensor conductor 13 is a rod-shaped conductor that is covered and only the tip is exposed, and is disposed in the front-to-rear direction of the housing 11. The tip is disposed so that it is in intimate contact with the rear of the front surface of the housing 11. Meanwhile, the intermediate portion M1 of the housing 11 to which the sensor conductor 13 is in intimate contact is formed thin like a film, for example 0.5 mm thick, compared to the surrounding area.

By providing a thin section between the two outlet holes 12 and arranging the sensor conductor 13 in this way, when a tracking discharge occurs between the blades of the connected plug, the heat causes carbonization between the outlet holes 12 of the housing 11, and eventually the area where the sensor conductor 13 is in close contact is carbonized. This carbonization changes the middle area M1, which should have been an insulator, into a conductor, and the current of the tracking discharge flows into the sensor conductor 13 through the carbonized area. As a result, the tracking detection unit connected to the sensor conductor 13 detects tracking and determines that tracking has occurred.

In this way, the sensor conductor 13 is disposed inside the housing 11, and the tracking discharge carbonizes the portion of the housing 11 where the sensor conductor 13 is disposed, causing the tracking discharge current to flow into the sensor conductor 13, and the tracking discharge is detected.

Fig. 4 shows yet another embodiment of the tracking detection structure, which is an explanatory diagram of a circuit breaker in which the structure is provided. Fig. 4(a) is an external view of the circuit breaker with the terminal portion enlarged, and Fig. 4(b) is an explanatory diagram of the cross section taken along line B-B, showing a vertical cross section of the intermediate portion M2 of the terminal portion.
In Fig. 4, reference numeral 21 denotes a housing of the circuit breaker 20, 22 denotes a terminal base constituting a terminal portion, which are formed in pairs, and terminal screws screwed into the terminal bases 22 are omitted. The housing 21 is made of synthetic resin, and the two terminal bases 22 are electric circuit connecting portions, with an insulating wall 23 formed between them.

The sensor conductor 13 is disposed inside this insulating wall 23, and is not visible from the outside, as shown in FIG. 4(a). As shown in FIG. 4(b), the sensor conductor 13 is disposed in the middle portion M2 of the insulating wall 23 between the terminal bases 22, and this middle portion M2 is formed in a thin film shape. The sensor conductor 13 is disposed behind this middle portion M2. The sensor conductor 13 is disposed so that its tip is in close contact with the insulating wall 23.

By providing a thin portion in the insulating wall 23 between the terminal bases 22 and arranging the sensor conductor 13 in this manner, tracking discharge is detected as follows.
The tracking discharge that occurs between the electric wires connected to the terminal base 22 occurs so as to come into contact with the insulating wall 23. Therefore, the heat carbonizes the insulating wall 23, and eventually the thin-walled portion at the front of the sensor conductor 13 carbonizes, and the portion that should have been an insulator becomes conductive, and the tracking discharge current flows into the sensor conductor 13 through the carbonized portion. As a result, the tracking detection portion connected to the sensor conductor 13 detects tracking and determines that tracking has occurred.

In this way, the sensor conductor 13 is disposed inside the housing 21, and when the housing 21 is carbonized by the tracking discharge, the tracking discharge current flows into the sensor conductor 13, making it possible to detect the tracking discharge.

In the above embodiment, a tracking detection structure is provided in the board 1, the housing 11 of the outlet, and the housing 21 of the circuit breaker. However, the tracking detection structure can also be applied to other connection parts, such as terminal blocks, and a tracking detection structure can be provided in the same way as the housing 21 of the circuit breaker by embedding a sensor conductor in the insulating wall between the terminals.

1: Printed circuit board, 2: Connector, 3: Exposed electrical circuit, 4: Sensor conductor, 5: Soldering area (electrical circuit connection area), 6: Resist, 10: Outlet, 11: Housing, 12: Outlet hole (electrical circuit connection area), 13: Sensor conductor, 20: Circuit breaker, 21: Housing, 22: Terminal base (electrical circuit connection area), 23: Insulating wall, M1, M2: Intermediate area, L: Electric wire, S: Discharge current.

Claims (3)

A tracking detection structure for detecting a tracking discharge occurring at an electric path connection portion,
A sensor conductor for detecting a current generated by a tracking discharge is disposed between the electrodes of the electric path connection part at a portion where a tracking discharge may occur,
A tracking detection structure, characterized in that the detection portion of the sensor conductor is covered with a film-like insulator that is carbonized or scattered by the generated tracking discharge. The sensor conductor is disposed inside a synthetic resin housing having a pair of connection terminals constituting the electric path connection portion, with a tip end of the sensor conductor being disposed between the electrodes of the connection terminals and facing outward.
2. The tracking detection structure according to claim 1, wherein the space between the electrodes of the housing where the tip of the sensor conductor is disposed is formed thin like a film. A pair of exposed electric paths for connecting a connector for connecting electric wires is patterned on the printed circuit board as the electric path connection portion;
2. The tracking detection structure according to claim 1, wherein the sensor conductor is patterned between the pair of exposed electrical paths, and the upper portion of the sensor conductor is covered with a resist.

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