JPH0511733U - Multi-circuit switch - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a multi-circuit switch which can measure a decrease in insulation resistance more safely and easily. [Structure] In a multi-circuit switch 1, a shield wire 20 of a cable on the power source side and a load side is led to a terminal 30 on the power source side formed on the front surface of the switch and connected, and a terminal on the ground side is located close to the terminal 30. 31 and connect this to the ground,
Short-circuit pieces 32, 3 that can open and close both terminals 30, 31
In addition to connecting with 3, the terminals of the measuring device can be connected between both terminals 30 and 31. This eliminates the possibility of electric shock due to leakage current even if an ammeter is connected because it is always in a short-circuit state.In addition, if the terminals of the ammeter are connected to both terminals and the short-circuit piece is removed during measurement, the current will flow to the ammeter. Since it flows, it can be easily measured and work efficiency can be improved.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a multi-circuit switch, and more particularly to a multi-circuit switch that allows easy inspection of cable deterioration.

[0002]

[Prior Art]

 Conventionally, a cable connected to a multi-circuit switch has its sheath side connected to a ground terminal provided in the multi-circuit switch. Then, in order to check whether the insulation deterioration of the cable has occurred due to the water tree phenomenon, etc., a cable insulation deterioration test is regularly performed.

In the conventional cable insulation deterioration test, the shielded wire led out from the sheath of the cable connected to the ground terminal of the multi-circuit switch is temporarily removed from the ground terminal of the multi-circuit switch, and a current is applied to the ground terminal. A meter is connected to measure whether leakage current is flowing or not.

[0004]

[Problems to be solved by the device]

 However, in such a conventional multi-circuit switch, when the cable is deteriorated and there is a leakage current, there is a possibility that an operator may get an electric shock when the cable is temporarily disconnected from the ground terminal as described above. Moreover, the work of the cable insulation deterioration test was very troublesome because the shield wire had to be removed once and an ammeter had to be connected between this and the ground.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a multi-circuit switch which can measure a decrease in insulation resistance more safely and easily.

[0006]

Means for Solving the Problems In order to achieve the above object, the present invention provides a multi-circuit switch in which a shield wire of a power supply side and a load side cable is led to a power supply side terminal formed on the front surface of the switch. Connect the ground side terminal close to the terminal, connect it to the ground, and connect both terminals with a shorting piece that can be opened and closed, and connect the terminal of the measuring device between both terminals. What is done is the gist.

[0007]

[Action]

 According to the above configuration, the short-circuit piece connects between the terminal on the power supply side and the terminal on the ground side, so that the leakage current is grounded by this short-circuit piece. Then, in a short circuit condition, connect the ammeter to the power supply side terminal and the ground side terminal, and then open the shorting piece, and then the current will flow through the ammeter so that the insulation deterioration state of the shielded wire can be measured safely. It will be possible.

[0008]

【Example】

 Hereinafter, an embodiment of the multi-circuit switch of the present invention will be described in detail with reference to the drawings.

A main body case 2 of the multi-circuit switch 1 is formed in a box shape, and an opening / closing door 4 is attached to an opening 3 on the front surface thereof. The multi-circuit switch 1 is installed on a manhole (not shown) on a base 7. Further, an air vent hole 11 is formed below the opening / closing door 4 on the front surface of the base 7.

A cable connection chamber 5 is formed below the switchgear main body support plate 8 in the main body case 2, and an open / close chamber including three switches is formed above the cable connection chamber 5. A common busbar 9 for three phases molded with epoxy resin is placed on the support plate 8, and fixed electrodes (not shown) forming a pair of three circuits are arranged on the common busbar 9. One of them is electrically connected to the common bus bar 9, and the other is connected to a cable connection terminal 10 projecting into the cable connection chamber 5.

An opening / closing lid 12 having a movable electrode (not shown) that can be connected to the fixed electrode of each circuit is provided above the common bus bar 9 for each circuit via a mechanism section 19. It

When the opening / closing lid 12 is moved downward, a movable electrode (not shown) comes into contact with a fixed electrode in the branching device body 9 to be in a closed state, and when it is moved upward, both electrodes are separated from each other to be in an opened state. .. In the closed state, the characters "ON" can be read from the lower transparent window 15 of the front panel 13, and in the open state, the characters "OFF" are read from the upper transparent window 16. It is readable.

The opening / closing lid 12 is configured to move up and down along a pair of support columns 17, 17 arranged for each circuit, and is opened by the biasing force of an opening spring 18 attached to the support column 17. It comes to be in a state.

The mechanical unit 19 can be manually or automatically operated. A terminal mounting plate 23 is attached to a mounting piece 21 on the lower side of the front surface of the branching device main body supporting plate 8 with machine screws 22. The terminal mounting plate 23 is an elongated rectangular metal plate, and is located near the center and left and right end portions of the front surface of the terminal mounting plate 23, that is, at three positions corresponding to the three branching device main bodies 9. A pair of test terminals 30 and 31, which are a power source side terminal and a ground side terminal, are attached close to each other.

The body shafts 30a and 31a of both test terminals 30 and 31 are inserted into a mounting case 42 made of insulating resin so that the terminal mounting plate 23 and the body shafts 30a and 31a are not in contact with each other. The case 42 is fixed to the terminal mounting plate 23.

The mounting case 42 is divided into two parts, and the tubular portion 42 c of the front-side divided piece 42 a sandwiching the terminal mounting plate 23 is protruded to the rear surface side through the insertion hole 23 a of the terminal mounting plate 23 and divided into the rear surface side. It is integrated with the piece 42b by engaging with it.

A nut 37 that is screwed into a thread groove formed on the main body shafts 30a and 31a is integrally formed with the split piece 42a at the front of the split piece 42a, and is formed outside the split piece 42b on the back side. The mounting case 42 is tightened and securely fixed in cooperation with the nut 45 screwed to the shafts 30a and 31a.

Color rings 35 and 36 of different colors are sandwiched between the divided piece 42a on the front side and the terminal mounting plate 23 according to the type of both test terminals 30 and 31. An insulating tightening body 38, which is integrally formed with the nut 39, is fitted and inserted in the body shafts 30a and 31a in front of the front-side divided piece 42a in a threaded relationship between the nut 39 and the body shafts 30a and 31a. ing. A short-circuit piece 32, which will be described later, is inserted between the divided piece 42a on the front surface side and the insulating tightening body 38.

An insulating tightening body 40 in which a nut 41 is integrally formed at the front ends of the body shafts 30 a and 31 a is screwed to the body shafts 30 a and 31 a via the nut 41. Then, another short-circuit piece 33 is inserted between one end edge of the nut 41 and the flange portions 30b, 31b formed on the front sides of the main body shafts 30a, 31a.

Of the pair of test terminals 30 and 31, the terminal 30 on the right side in FIGS. 1 to 3 is a ground terminal, and a nut 45 and a lock nut 50 on the rear surface side of the terminal mounting plate 23 interpose a washer 51. And the ground lead wire 34 is attached. Each terminal 30 provided at three places is connected in series by a lead wire 34 and is connected to a ground terminal bolt (not shown) to be grounded.

Further, a shield wire 20 derived from a cable wire of each phase for each circuit is provided at a terminal 31 on the left side of the figure with a washer 51 with a nut 45 and a lock nut 45 on the back side of the terminal mounting plate 23. It is connected to each terminal 31 via. That is, the three phases connected in parallel to each pole are collectively guided to this shielded wire. FIG. 5 shows these wiring states.

The short-circuit pieces 32, 33 have engaging portions 46 a that engage with the main body shafts 30 a, 31 a at both ends of the plate-shaped metal piece 46, and have a flat square shape at the center of the plate-shaped metal piece. The plate body 47 made of an insulating resin is integrally molded, and has a shape in which a metal piece is projected like a wing from the side surfaces of the plate body 47 facing each other.

The short-circuit piece 32, which is inserted into the gap between the divided piece 42a on the front side and the insulating tightening body 38, is inserted, and the insulating tightening body 38 is rotated and tightened so as to connect between the test terminals 30, 31. Securely fixed to. Further, a short-circuit piece 33 that is inserted into a gap between one end edge of the nut 41 and the flange portions 30b and 31b formed near the front of the main body shafts 30a and 31a is also inserted, and the insulation tightening body 40 is rotated and tightened. Then, it is surely fixed between both test terminals 30 and 31.

Next, a method of connecting the ammeter A for measuring insulation deterioration in the multi-circuit switch having such a test terminal will be described. This multi-circuit switch has three circuits, and each circuit can be measured. First, as shown in FIG. 3, the test pieces 30 and 31 are always short-circuited by the shorting pieces 32 and 33. Then, the short-circuit piece 33 between the test terminals 30 and 31 of either circuit is loosened by turning the insulating tightening body 40 in the opposite direction, and the connecting terminal of the ammeter A is inserted into the removed gap, and the connecting terminal tip is inserted. The engaging portion of the terminal is engaged with the main body shafts 30a and 31a, and the insulating tightening body 40 is rotated and fixed. Then, when the other short-circuit piece 32 is loosened and the insulation clamp body 38 is loosened, the current starts flowing through the ammeter A, and the current value measured there is compared with the rated current to check the insulation deterioration state.

With this configuration, since the test terminals 30 and 31 are already short-circuited when the ammeter A is connected, there is no electric shock during the connection work due to the leakage current. In addition, the shield wire is removed for each measurement, and it is not necessary to connect the ammeter A between this shield wire and the ground, and work efficiency can be measured.

Further, since the short-circuit piece 33 can be removed and the ammeter A can be connected to it instead, it is not necessary to separately provide a connection terminal for the ammeter A. Although the embodiments of the present invention have been described in detail above, the present invention can be implemented in other modes.

For example, in the above embodiment, the insulation resistance was measured for one circuit as the pair of test terminals 30 and 31, that is, for the entire three phases of U, V, and W. However, as shown in FIG. It is also possible to increase the number and connect each phase to each terminal and measure the deterioration state for each phase.

This is because the test terminals T1, T2, T3 are arranged for each phase (U, V, W), and the three ground terminals T4, T5, T6 corresponding thereto are arranged so that adjacent terminals are mutually connected. To each other by short-circuit pieces S1 to S6, and the short-circuit pieces can be freely short-circuited or opened (FIG. 6a).

In the case of such a configuration, for example, if only the V phase is measured, the short-circuit piece S2 between the V-phase test terminal T2 and the ground terminal T5 is removed and the current meter A After connecting, the short-circuit pieces S4 and S5 between the U-phase and the V-phase and between the V-phase and the W-phase are opened as shown in FIG. Then, it is possible to measure the deterioration state of only the V phase (Fig. 6b).

Of course, as shown in FIG. 6c, for example, if the short-circuit piece S1 between the test terminals T1 and T4 is removed and the ammeter A is connected to the test piece T1 and then the short-circuit pieces S2 and S3 are removed, the entire three-phase is deteriorated. It is also possible to measure.

In this case, the number of ground terminals is not limited to three and may be one. Further, in the above embodiment, one of the two short-circuit pieces is removed and the ammeter A is connected thereto, but only one short-circuit piece is provided to provide a connection terminal for the ammeter A which is not always used. You are also free to do so.

Other than three circuits, the present invention can be applied as long as it is a multi-circuit switch, and the present invention can be appropriately modified and implemented without departing from the spirit of the invention.

[0033]

[Effect of the device]

 As described above in detail, in the present invention, in the multi-circuit switch, the shield wire of the cable on the power supply side and the load side is guided to the terminal on the power supply side formed on the peripheral surface of the switch and connected to the terminal on the power supply side. A grounding side terminal is provided at a close position and is connected to earth, and both terminals are connected with a short-circuit piece that can be opened and closed, and the terminals of the measuring device can be connected between both terminals to always short-circuit. Since it is in a state, even if an ammeter is connected, there will be no accident that you will get an electric shock due to leakage current, and at the time of measurement, if you connect the terminals of the ammeter to both terminals and then remove the shorting piece, the current will flow to the ammeter, which is easy. This has the effect of making it possible to perform measurements and improve work efficiency.

[Brief description of drawings]

FIG. 1 is a partially omitted front view of a multi-circuit switch according to an embodiment of the present invention.

FIG. 2 is a partially enlarged partially cutaway front view of the same embodiment.

FIG. 3 is a partial cross-sectional plan view illustrating a state in which a short-circuit piece is connected to the test terminal of the same example.

FIG. 4 is a perspective view of a short-circuit piece for connecting the test terminals of the same embodiment.

FIG. 5 is an explanatory diagram illustrating a state in which an ammeter is connected to the test terminal of the same example.

6A and 6B are explanatory views for explaining a wiring state of a shield wire to a test terminal in another embodiment, where a is a normal state in which an ammeter is not connected, and b is an ammeter connected and only V phase is shown. The measurement state of 3) and the state of c measuring 3 phases will be described.

[Explanation of symbols]

1 ... Multi-circuit switch, 20 ... Shielded wire, 30, T1, T
2, T3 ... Power source side terminal, 31, T4, T5, T6 ... Ground side terminal, 32, 33, S1, S2, S3, S4, S
5 ... Shorting piece.

Claims (1)

[Claims for utility model registration] [Claim 1] In the multi-circuit switch (1), the power source side,
Position where the shielded wire (20) of the load side cable is led to and connected to the power source side terminals (30, T1, T2, T3) formed on the front of the switch, and close to the terminals (30, T1, T2, T3) The ground side terminals (31, T4, T5, T6) are provided and connected to the ground, and both terminals (30, T1, T6) are connected.
Short circuit pieces (32, 33, S1, S2, S3, S4, S that enable open / close connection of 2, T3, 31, T4, T5, T6)
5) and connect both terminals (30, T1, T2,
A multi-circuit switch characterized in that terminals of a measuring device can be connected between T3, 31, T4, T5, T6).