JPH0129267B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an overcurrent indicator suitable for being installed in each phase of a distribution line, etc., and detecting and displaying an overcurrent for each phase when an overcurrent flows therein. It is something.

2. Description of the Related Art Overcurrent indicators are known that use electromagnetic force caused by the overcurrent to indicate an overcurrent when an overcurrent flows through a line. However, in conventional overcurrent indicators, the driving force to display the overcurrent when an overcurrent flows is obtained mostly from the overcurrent, but recovery is performed manually or by using an auxiliary power source. This is done by using a complicated crank mechanism. The crank mechanism is often also used as a drive mechanism for overcurrent indication.

The disadvantages of conventional devices of this type are that they require maintenance and are complex.

It is therefore an object of the invention to provide an overcurrent indicator which does not have these drawbacks.

To achieve this object, the present invention provides a fixed iron core having a window hole for passing a through conductor therethrough, and when an overcurrent flows through the through conductor passing through the window hole, it is attracted to the fixed iron core and moves linearly. a return spring that returns and holds the movable core in a non-attracting position when no overcurrent is flowing through the through conductor; An overcurrent indicator comprising an overcurrent indicator having an overcurrent display surface that is exposed or hidden depending on whether the overcurrent display surface is present or not, and a reflective mirror fixedly arranged so that the overcurrent display surface can be easily seen from the outside. This is a display device.

Further, the present invention provides a fixed iron core having a window hole for passing a through conductor therethrough, a movable iron core that is attracted to the fixed iron core and moves linearly when an overcurrent flows through the through conductor passing through the window hole, A return spring that returns and holds the movable iron core in a non-attracting position when no overcurrent flows through the through conductor; an overcurrent indicator having an overcurrent display surface that is exposed or hidden;
a reflecting mirror fixedly arranged so that the overcurrent display surface is easily visible from the outside; and a reflecting mirror connected to the movable iron core;
The overcurrent indicator is equipped with an air dash pot that enables instantaneous operation when the movable iron core is attracted to the fixed iron core, and performs a time-limited return when the movable iron core separates from the fixed iron core and returns to its original position. It is something.

The dowel pot is provided in communication with a bellows that expands and contracts in conjunction with the movable iron core, and an inner chamber of the bellows, and is opened during suction operation of the movable iron core to open the inner chamber of the bellows to the atmosphere. The bellows may be constructed of a check valve that closes during the return operation, and a pore mechanism having a pore that communicates with the inner chamber of the bellows at one end and opens to the atmosphere at the other end.

Hereinafter, the present invention will be explained in more detail based on embodiments shown in the drawings.

The overcurrent indicator of this embodiment has a closed casing consisting of a substrate 2 made of a non-magnetic material and a transparent case 3 that engages with the substrate 2. A pair of fixed core legs 4 and 5 are fixed to the base plate 2 through the base plate 2, and a yoke 6 is arranged outside the casing so as to bridge the fixed cores 4 and 5. The fixed core legs 4 and 5 and the yoke 6 constitute a fixed core. A window hole 7 formed inside the fixed core legs 4, 5, the substrate 2, and the yoke 6 is used to pass a through conductor 8 through which overcurrent is to be detected. The yoke 6 is pivotally connected at one end to an auxiliary piece 9 fixed to the fixed core leg 5 by a pin 10 in order to conveniently pass the through conductor 8 into the window hole 7 and remove it therefrom. The other end of the auxiliary piece 11 is fixed to the fixed core leg 4, and the nut 12 is screwed into a screw (not shown) passing through the yoke 6 to maintain the assembled state.

A movable core 13 that can be attracted to the fixed core legs 4 and 5 is provided within the transparent case 3. Movable iron core 1
A bellows 14 is arranged between the base plate 3 and the base plate 2, and the bellows 14 is connected to the retaining plate 1 which also serves as a spring seat on the base plate 2 side.
5 and is fixed to the substrate 2 with screws 16. The movable core side of the bellows 14 is free or bonded to the movable core 13, and within the bellows 14, a spring seat 17 is bonded to the movable core side by adhesive or the like. In the bellows 14, between the spring seat 17 and the holding plate 15, the movable iron core 1
A return spring 18 for return to 3 is provided.

The inner chamber of the bellows 14 is communicated via the central through hole 19 of the holding plate 15, its own central through hole 20, and the communication hole 22 formed by the groove provided in the base plate 2 and the closing means 21 that closes the groove. One end communicates with the check valve 30, and the other communicates with the pore mechanism 40, and these series of pneumatic means constitute an air dump pot according to the present invention.

A rod-shaped overcurrent indicator 23 is provided on the inner side of the end surface of the transparent case 3 and protrudes from there toward the movable iron core 13. A part of the overcurrent indicator 23, here the tip, is formed slightly thick, and its outer peripheral surface is configured as an overcurrent indicator surface 24. Overcurrent display screen 2
4 may be a single colored surface, or may be a letter or symbol for overcurrent indication, or a combination of both. The overcurrent display screen 24 is always displayed (when the movable iron core 13
(when not attracted) is covered by a cover 25 attached to the movable core 13, and when the movable core 13 is attracted, the cover 25 moves together with the movable core 13 and is exposed. The relationship between the movable part and the fixed part for overcurrent display according to the movement of the movable core 13 may be reversed to that described above.The overcurrent indicator is attached to the movable core 13, and the cover is placed on the side of the transparent case. It can perform exactly the same function as above even if it is installed in A conical reflecting mirror 26 is arranged so that the exposed overcurrent display surface 24 can be clearly seen from the outside of the end surface of the transparent case 3. The reflecting mirror 26 is attached to the transparent case 3 at its outer peripheral end.

The check valve 30 is constructed on the inner surface of the substrate 2, and includes a valve body 31 that closes or opens the opening of the communication hole 22.
, a valve body housing casing 33 screwed to the base plate 2 by screws 32, and a relatively weak return spring 34 housed within the casing 33 so as to act on the valve body 31 in the closing direction. There is. The valve stem penetrating portion of the casing 33 functions as an air escape hole 35.

The pore mechanism 40 is configured with a closing plate 42 having a pore 41 arranged so as to close another opening of the communication hole 22 as a main member. Closing plate 4
2 is fixed onto the substrate 2 by a presser plate 45 via packings 43 and 44. The holding plate 45 is screwed to the substrate 2 with screws 46. The gaskets 43, 44 and the holding plate 45 have a through hole coaxial with the small hole 41 and larger than the small hole 41.
Air flow resistance in this portion is mainly determined by the pores 41. The diameter of the pores 41 is on the order of 0.1 mm.

In the overcurrent indicator configured as described above, when no overcurrent is flowing through the through conductor 8, the attractive force acting on the movable iron core 13 is weak or zero, and the spring force of the return spring 18 is reduced. Movable iron core 1
3 is in a non-suction position, that is, a non-operating position, as shown, which is separated by a gap G from the fixed cores 4 and 5. Therefore, the overcurrent display surface 24 is covered by the cover 25 and no overcurrent display is performed.

When an overcurrent flows through the through conductor 8 due to an overload or a short circuit, the attraction force generated by this as a magnetomotive force increases, and the movable core 13 is attracted to the fixed cores 4 and 5 against the spring force of the return spring 18. Ru. At this time, the bellows 14 is compressed in conjunction with the movable iron core 13. Due to this compression, the internal pressure of the bellows 14 increases, the valve body 31 of the check valve 30 is pushed open, and the inner chamber of the bellows 14 and the communication hole 22 are opened to the outside of the bellows via the air escape hole 35. Therefore, the movable core 13 receives almost no resistance during the suction operation, and the operation is substantially instantaneous. When the movable iron core 13 is attracted, the cover 25 also moves together with it, and the overcurrent display surface 24 is exposed. The overcurrent display surface 24 can be easily confirmed visually from the outside of the end face of the transparent case 3 due to the action of the reflecting mirror 26.

When an overcurrent flows in an electrical circuit, a protection device generally operates and cuts off the line, so the situation where an overload current or short circuit current is flowing is generally resolved in a very short time. be. Although the overcurrent indicator of the present invention is of a self-resetting type, it is inconvenient for maintenance and inspection if the overcurrent indication disappears immediately upon interruption of the overcurrent. Therefore, the overcurrent indicator of the present invention is devised so that in the case of recovery, the recovery is delayed due to the action of the pore mechanism 40.

That is, when the overcurrent ceases to flow through the through conductor 8, the magnetic attraction force acting on the movable iron core 13 first disappears, and the movable iron core 13 attempts to return to the illustrated non-operating position by the spring force of the return spring 18. However, a bellows 14 is connected to the movable core 13, and a check valve 30 and a pore mechanism 40 are connected to the bellows 14 through a communication hole 22. When the bellows 14 attempts to shift from the compressed state to the expanded state as the movable core 14 returns, the internal pressure of the bellows 14 becomes negative, so the check valve 30 closes first. The equilibrium effect of this negative pressure is caused by the pore 4
1, so the bellows 1
The expansion operation No. 4, that is, the return operation of the movable iron core 13, is not performed instantaneously, but is performed gradually over about 1 to 2 hours. During this time, the overcurrent display surface 24 continues to be exposed, so that the operator can easily visually check it even after the overcurrent has been cut off. When the movable core 13 is completely restored, the overcurrent display surface 24 is completely covered by the cover 25, and the entire device is restored to its initial state.

As described above, the overcurrent indicator of the present invention is an automatic reset type that displays instantaneously using electromagnetic force caused by overcurrent and has a delay characteristic, and is less prone to malfunction or damage due to surges and Since no fluid is used, there are almost no changes in characteristics due to temperature. Furthermore, the overcurrent indicator of the present invention does not require an auxiliary power source, so it is safe and economical. Further, since it is an automatic reset type, the overcurrent indicator of the present invention has many practical advantages, such as requiring less maintenance.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of an overcurrent indicator according to the present invention, FIG. 2 is a sectional view taken from the line - in FIG. 1, and FIG. 3 is a sectional view taken from the line - in FIG. 2. The cross-sectional view, FIG. 4, is a cross-sectional view taken along the - line in FIG. 2. 4, 5...Fixed core leg, 6...Yoke, 7...Window hole,
8... Penetration conductor, 13... Movable iron core, 14... Bellows, 18... Return spring, 22... Communication hole, 23... Overcurrent indicator, 24... Overcurrent display surface, 25... Cover,
26... Reflector, 30... Check valve, 40... Pore mechanism.

Claims (1)

[Scope of Claims] 1. A fixed iron core having a window hole for passing a through conductor therethrough, and a movable iron core that is attracted to the fixed iron core and moves linearly when an overcurrent flows through the through conductor passing through the window hole. , a return spring that returns and holds the movable iron core in a non-attraction position when no overcurrent is flowing through the through conductor, and a return spring that responds to whether the movable iron core is in an attraction position or a non-attraction position with respect to the fixed iron core. An overcurrent indicator comprising: an overcurrent indicator having an overcurrent display surface that is exposed or hidden; and a reflective mirror fixedly arranged so that the overcurrent display surface can be easily seen from the outside. 2. A fixed iron core having a window hole for passing the through conductor, a movable iron core that is attracted to the fixed iron core and moves linearly when an overcurrent flows through the through conductor passing through the window hole, A return spring that returns and holds the movable core in a non-attraction position when no current is flowing; and a return spring that is exposed or hidden depending on whether the movable core is in a suction position or a non-attraction position with respect to the fixed core. an overcurrent indicator having an overcurrent display surface that can be easily viewed from the outside; a reflector that is fixedly arranged so that the overcurrent display surface can be easily seen from the outside; An overcurrent indicator comprising an air dash pot that enables instantaneous operation when the movable iron core is separated from the fixed iron core and performs a time-limited return when the movable iron core is separated from the fixed iron core and returns. 3. The dowel pot is provided in communication with a bellows that expands and contracts in conjunction with the movable iron core, and an inner chamber of the bellows, and opens during a suction operation of the movable iron core to open the bellows inner chamber to the atmosphere, and Claim 2, comprising: a check valve that closes during the return operation of the movable iron core; and a pore mechanism having a pore that communicates with the inner chamber of the bellows at one end and opens to the atmosphere at the other end. Overcurrent indicator as described in section.