JP2011174780A - Voltage testing plug - Google Patents

Abstract

Provided is a voltage test plug that can prevent a momentary disconnection when measuring a voltage even if it is connected to or disconnected from a voltage test terminal of the electric device, and can prevent a short circuit between phases even when a tester is connected when testing the electric device. That is.
A fuse 28 is connected between an upper conductor 22 and an outer terminal 24 of a voltage test plug 21, and the fuse 28 is a test voltage applied in a normal test from a tester 27 to an electric device 12. In the case where a short-circuit current of a short circuit between phases of the external power source flows through the tester 27 that occurs when the tester 27 is connected and disconnected from the voltage test terminal while the test line of the tester 27 is connected, Operates before the fuse on the external power supply side.
[Selection] Figure 1

Description

  The present invention relates to a voltage test plug which is inserted into a voltage test terminal of an electric device and used for testing and measuring a voltage of the electric device.

  The voltage test plug is used as a device to be inserted into the voltage test terminal of an electrical device and to disconnect the electrical device from an external power source, for example, the power system, in inspection and testing of electrical devices such as substation relay panels and monitoring control panels. Yes. Then, instead of an external power source, a tester is connected to the electrical device and used to apply a test input from the tester to the electrical device.

The voltage test plug currently used is short-circuited between the phases via a tester having a small internal resistance when the voltage test plug with the test wire of the tester connected is connected or disconnected. When the phase is short-circuited,
The secondary fuse (hereinafter referred to as the main body fuse) of the instrument transformer (hereinafter referred to as the transformer), which is an external power supply, is blown out, the protective relay is erroneously displayed, or a malfunction such as an electric shock is caused. Sometimes. Therefore, for safety reasons, it is obliged not to perform “insertion / extraction” of the voltage test plug while the test line of the tester is connected.

  4 is a configuration diagram of a conventional voltage test terminal and a voltage test plug. FIG. 4A is a configuration diagram illustrating an example of a voltage test terminal, and FIG. 4B is a plan view illustrating an example of a voltage test plug. is there. As shown in FIG. 4A, the voltage test terminal 11 includes electrical device connection terminals 13a, 13b, 13c connected to the electrical device 12, and external power supply terminals 14a, 14b, 14c connected to an external power source. Have. FIG. 4 shows a case where the power source stepped down by the three-phase transformer 16 is supplied from the power system 15 as the external power source. Main body fuses 17 a, 17 b, and 17 c are respectively provided on the secondary side of the transformer 16, and are connected to the external power supply terminals 14 a, 14 b, and 14 c of the voltage test terminal 11.

  Each terminal 11a, 11b, 11c of the voltage test terminal 11 has a first contact 18a, 18b, 18c and a second contact between the electric device connection terminals 13a, 13b, 13c and the external power supply terminals 14a, 14b, 14c. 19a, 19b, 19c, and further, third contacts 20a, 20b, 20c for disconnecting the connection with the external power source.

  On the other hand, the voltage test plug 21 has plugs 21a, 21b, and 21c inserted into the terminals 11a, 11b, and 11c of the voltage test terminal 11, as shown in FIG. Each plug 21a, 21b, 21c of the voltage test plug 21 has an upper conductor 22a, 22b, 22c and a lower conductor 23a, 23b, 23c, respectively, and an outer terminal 24a connected to the upper conductor 22a, 22b, 22c, 24b, 24c and inner terminals 25a, 25b, 25c connected to the lower conductors 23a, 23b, 23c.

  The voltage test plug 21 is inserted into the voltage test terminal 11 when testing the electric device 12 or when measuring a voltage applied to the electric device from an external power source. When the voltage test plug 21 is not inserted into the voltage test terminal 11, the third contacts 20a, 20b, 20c are closed, so that the external power supply terminals 14a, 14b, 14c, the third contact 20a from the external power source. , 20b, 20c and the electric device connection terminals 13a, 13b, 13c, power is supplied to the electric device 12.

  When testing the electrical device 12, after the voltage test plug 21 is inserted into the voltage test terminal 11, the tester is connected to the outer terminals 24a, 24b, 24c. For example, a tester is connected between the outer terminals 24a and 24b, and a test voltage is applied between the a phase and the b phase. On the other hand, when measuring the voltage applied to the electric device from the external power source, the voltage test plug is connected with the connecting piece connected between the outer terminals 24a, 24b, 24c and the inner terminals 25a, 25b, 25c. 21 is inserted into the voltage test terminal 11, and a voltage measuring instrument is connected to the connection piece connected to the outer terminals 24a, 24b, 24c or the voltage is measured. For example, a voltage measuring device is connected between the outer terminals 24a and 24b, and the voltage between the a phase and the b phase is measured.

  FIG. 5 is an operation explanatory diagram when the conventional voltage test plug 21 is inserted into the voltage test terminal 11 during voltage measurement. FIG. 5A shows the voltage test plug 21 inserted halfway through the voltage test terminal 11. FIG. 5 (b) shows the case where the voltage test plug 21 is inserted to the end of the voltage test terminal 11, and the first contact 18a, 18b, 18c and the second contact. It is explanatory drawing at the time of contact | abutting to 19a, 19b, 19c.

  When measuring the voltage, connecting pieces 26a, 26b, 26c are connected between the outer terminals 24a, 24b, 24c of the voltage test plug 21 and the inner terminals 25a, 25b, 25c, and the voltage test plug 21 is connected to the voltage in this state. Insert into test terminal 11. As shown in FIG. 5A, when the voltage test plug 21 is inserted to the position of the first contacts 18a, 18b, 18c in the middle of the voltage test terminal 11, the upper conductors 22a, 22b of each of the voltage test plugs 21 are inserted. 22c and the lower conductors 23a, 23b, 23c abut on the first contacts 18a, 18b, 18c. Thus, a short circuit via the first contacts 18a, 18b, and 18c is in parallel with the third contacts 20a, 20b, and 20c between the electric device connection terminals 13a, 13b, and 13c and the external power supply terminals 14a, 14b, and 14c. Formed.

  That is, electrical device connection terminals 13a, 13b, 13c, first contacts 18a, 18b, 18c, upper conductors 22a, 22b, 22c, outer terminals 24a, 24b, 24c, connection pieces 26a, 26b, 26c, inner terminals 25a, 25b 25c, the lower conductors 23a, 23b, 23c and the external power supply terminals 14a, 14b, 14c are formed as a short circuit. Therefore, the electric device 12 is connected to the transformer 16 (external power source) by a parallel circuit of the short circuit and the third contacts 20a, 20b, and 20c.

  As shown in FIG. 5 (b), when the voltage test plug 21 is inserted to the last position of the voltage test terminal 11, the upper conductors 22a, 22b, 22c and the lower conductors 23a, 23b, 23c contacts both of the first contacts 18a, 18b, 18c and the second contacts 19a, 19b, 19c. When the voltage test plug 21 contacts the second contacts 19a, 19b, and 19c, a short circuit is formed via the second contacts 19a, 19b, and 19c, and the third contacts 20a, 20b, and 20c are opened. Even if the third contacts 20a, 20b, and 20c are opened first without forming the short circuit through the second contacts 19a, 19b, and 19c, the short circuit through the first contacts 18a, 18b, and 18c. Is already formed, the power from the transformer 16 (external power supply) is supplied to the electric device 12 without being interrupted.

  As described above, the first contacts 18a, 18b, 18c and the second contacts 19a, 19b, 19c are prepared when the voltage is measured while the electric device 12 is kept in operation. This is to prevent a momentary interruption. That is, when the voltage test plug 21 is inserted to the position of the first contacts 18a, 18b, 18c, a short circuit is formed via the first contacts 18a, 18b, 18c, and the third contacts 20a, 20b, 20c In a closed state, a circuit that flows from the external power source to the electric device 12 is formed in advance, and then, when the voltage test plug 21 is inserted to the positions of the second contacts 19a, 19b, and 19c, the second contact A short circuit is formed via 19a, 19b, 19c and the third contacts 20a, 20b, 20c are opened. Thereby, the power supply from an external power supply is supplied to the electric apparatus 12 without instantaneous interruption.

  In the state of FIG. 5B, for example, in order to measure the voltage between the a phase and the b phase, the voltage measuring device is connected between the outer terminals 24a and 24b or connected to the connection pieces 26a and 26b. , And measure the voltage between phase a and phase b.

  Next, FIG. 6 is an operation explanatory diagram when the conventional voltage test plug 21 is inserted into the voltage test terminal 11 when testing the electric device 12, and FIG. FIG. 6B is an explanatory view when the terminal 11 is inserted partway and contacts the first contacts 18a, 18b, 18c. FIG. 6B shows the voltage test plug 21 inserted to the end of the voltage test terminal 11, and the first contacts 18a, 18b. , 18c and second contacts 19a, 19b, 19c are explanatory diagrams when abutting.

  Unlike the case of the voltage measurement shown in FIG. 5, the voltage of the voltage test plug 21 without connecting the connection pieces 26a, 26b, 26c between the outer terminals 24a, 24b, 24c and the inner terminals 25a, 25b, 25c. Insert into test terminal 11. As shown in FIG. 6A, when the voltage test plug 21 is inserted to the position of the first contacts 18a, 18b, 18c in the middle of the voltage test terminal 11, the upper conductors 22a, 22b of each of the voltage test plugs 21 are inserted. 22c and the lower conductors 23a, 23b, 23c abut on the first contacts 18a, 18b, 18c. In this case, since the connection pieces 26a, 26b, 26c shown in FIG. 5 are not connected between the outer terminals 24a, 24b, 24c and the inner terminals 25a, 25b, 25c, the electric device connection terminals 13a, 13b, No short circuit is formed between 13c and the external power supply terminals 14a, 14b, 14c. In this state, the third contacts 20a, 20b, and 20c remain closed, and power is supplied to the electric device 12 from the transformer 16 (external power source) through the third contacts 20a, 20b, and 20c.

  As shown in FIG. 6 (b), when the voltage test plug 21 is inserted to the last position of the voltage test terminal 11, the upper conductors 22a, 22b, 22c and the lower conductors 23a, 23b, 23c contacts both of the first contacts 18a, 18b, 18c and the second contacts 19a, 19b, 19c. When the voltage test plug 21 contacts the second contacts 19a, 19b, and 19c, the third contacts 20a, 20b, and 20c are opened. In this case, since the connection pieces 26a, 26b, 26c shown in FIG. 5 are not connected between the outer terminals 24a, 24b, 24c and the inner terminals 25a, 25b, 25c, the second contacts 19a, 19b, 19c No short circuit is formed through this. Therefore, since the third contacts 20a, 20b, and 20c are opened, the power source from the transformer 16 (external power source) to the electrical device 12 is shut off.

  In this state, as shown in FIG. 7, the tester 27 is connected between the outer terminals 24 a, 24 b, and 24 c of the voltage test plug 21, and the test power is supplied from the tester 27 to the electrical device 12. FIG. 7 shows a case where a test is performed by applying a test voltage between the a phase and the b phase. That is, as shown by the arrow in FIG. 7, a test current flows and the electrical device 12 is tested.

  FIG. 8 is an operation explanatory diagram when the voltage test plug 21 is inserted into the voltage test terminal 11 while the tester 27 is connected when the electric device 12 is tested. As shown in FIG. 8, the voltage test plug 21 is inserted to the positions of the first contacts 18 a, 18 b, and 18 c of the voltage test terminal 11 while the tester 27 is connected between the outer terminals 24 a and 24 b of the voltage test plug 21. Then, the transformer 16 (external power supply) is short-circuited between the phases via the tester 27. Therefore, when connecting the test line of the tester 27 to the voltage test plug 21, as shown in FIGS. 6 and 7, first, after the voltage test plug 21 is completely inserted into the voltage test terminal 11, the test line is connected to the outer terminal 24. Decided to connect to.

  If the voltage test plug 21 is inserted to the position of the first contacts 18a, 18b, 18c of the voltage test terminal 11 while the test line of the tester 27 is connected, the upper conductors 22a of each of the voltage test plugs 21, 22b, 22c and the lower conductors 23a, 23b, 23c abut against the first contacts 18a, 18b, 18c, and the third contacts 20a, 20b, 20c remain closed. Therefore, from the transformer 16 (external power supply), the third contact 20a, the first contact 18a, the upper conductor 22a, the outer terminal 24a, the tester 27, the outer terminal 24b, the upper conductor 22b, the first contact 18b, and the third contact 20b. A circuit is formed that passes back to the transformer 16. Since the tester 27 is a voltage power source, the internal resistance is small, and a short circuit between phases of the transformer 16 is formed.

  Thus, when the conventional voltage test plug 21 is inserted into the voltage test terminal 11, the first contacts 18a, 18b, 18c and the second contacts 19a, 19b, 19c on the voltage test terminal 11 side are sequentially connected, When connected to the second contacts 19a, 19b, 19c, the third contacts 20a, 20b, 20c at the back are further opened and electrically separated.

  This is because two different operations are performed with the same structure when switching the connection from the external power source to the tester 27 when testing the electrical device 12 and when measuring the voltage while using the electrical device 12. Because. For this reason, when the voltage test plug 21 with the tester 27 connected is inserted, a phase-to-phase short circuit occurs when the voltage test plug 21 is in contact with the first contacts 18a, 18b, 18c being inserted due to the structure.

  To prevent this short circuit between phases, it is detected whether a closed circuit is formed between the test circuit and the voltage test plug, the position of the voltage test plug inserted into the voltage test terminal is detected, and the closed circuit is detected. Is detected and the position of the voltage test plug is detected before insertion, the insertion of the voltage test plug is blocked, while the closed circuit is detected and the voltage test plug is inserted when the voltage test plug is inserted. There is a device that prevents pulling out and prevents malfunction or damage of an electric device or an external voltage circuit by being connected or disconnected while a test circuit is connected to a voltage test plug (for example, see Patent Document 1).

  In addition, when the voltage test plug is inserted into the voltage test terminal, a first terminal (internal connection terminal) electrically connected to the terminal of the electric device and a second terminal electrically connected to the terminal of the tester Switch means (center connection terminal) capable of selectively electrically connecting and disconnecting the terminal (center connection terminal), the first terminal (internal connection terminal) and the second terminal (center connection terminal) ), And if necessary, slide the center connection terminal with respect to the voltage test plug housing by operating the nut of the voltage test plug. Or switching from “connected state” to “unconnected state” to improve the work efficiency of the voltage test and prevent wiring connection mistakes and operation mistakes (for example, Patent Document 2). reference).

Japanese Patent Laid-Open No. 7-12844 JP 2009-36599 A

  However, in Patent Document 1, since the insertion of the voltage test plug or the removal of the voltage test plug is prevented, a short circuit between the test circuit and the external power supply can be prevented. Is required and the structure is complicated. Moreover, since insertion / extraction is prevented, work efficiency is bad.

  In Patent Document 2, the voltage test plug is changed from “not connected” to “connected” or from “connected” to “not connected” by sliding the center connection terminal with respect to the voltage test plug housing. Since it is to be switched to “state”, a mechanism for that is required, the structure becomes complicated, and an operation for switching from “connected state” to “non-connected state” is required.

  An object of the present invention is to provide a voltage test plug that can prevent an instantaneous interruption during voltage measurement even when it is connected to or disconnected from a voltage test terminal of an electric device, and can prevent a short circuit between phases even when a tester is connected when testing an electric device. Is to provide.

  The voltage test plug according to the invention of claim 1 has a first contact and a second contact between an electric device connection terminal connected to an electric device and an external power supply terminal connected to an external power supply, and the external power supply When the electric device is tested, the third contact is opened to disconnect the electric device from the external power source and through the first and second contacts. When the voltage is measured by connecting a tester to the electrical device and measuring the voltage applied to the electrical device from the external power source, the electrical device is passed through the first contact and the second contact with the third contact open. And a lower conductor connected to the second contact via the first contact when inserted into the voltage test terminal in a voltage test plug for connecting the external power supply to the external power supply, A parallel circuit with the third contact is formed by the lower conductor and the first contact with the third contact closed while being inserted into the voltage test terminal and contacting the first contact. An upper conductor that opens the third contact while maintaining a connection with the second contact when contacted with the second contact via one contact, and the upper conductor that is connected to the lower conductor and measures the voltage An inner terminal for connecting one end of a connection piece for short-circuiting a conductor and the lower conductor, and the other end of the connection piece connected to the upper conductor for the voltage measurement to test the electric device A current that flows between the outer terminal for connecting the tester and the upper conductor and the outer terminal and that flows in the case of a test voltage applied from the tester to the electrical device in a normal test. Range is dynamic Without connecting the test line of the tester to the voltage test terminal, the short circuit current between the phases of the external power supply that occurs when the tester is connected to the voltage test terminal leads the main body fuse on the external power supply side. A voltage test plug comprising an operating fuse.

  A voltage test plug according to a second aspect of the present invention is the voltage test plug according to the first aspect of the present invention, wherein the capacity of the fuse is smaller than the short-circuit current of the short circuit between the phases of the external power supply and larger than the test voltage applied in a normal test. It is a capacity | capacitance which operate | moves with the electric current which flows into the said electric device when it applies.

  According to the first aspect of the present invention, a fuse is provided between the upper conductor and the outer terminal, and the fuse operates in a current range that flows in the case of a test voltage applied in a normal test from the tester to the electric device. First, it operates before the main body fuse on the external power supply side due to the short-circuit current of the phase of the external power supply via the tester that occurs when the test wire of the tester is connected to the voltage test terminal. Even when the tester is connected, it is possible to prevent a short circuit between the phases without operating the main body fuse even if the tester is connected to the voltage test terminal.

  According to the invention of claim 2, the capacity of the fuse is smaller than the short-circuit current of the interphase short circuit of the external power supply, and operates with the current flowing in the electric device when a voltage larger than the test voltage applied in the normal test is applied. Therefore, the electrical device can be protected not only when the external power supply is short-circuited between phases but also when an overvoltage is accidentally applied as a test voltage during the test.

The side surface conceptual diagram of the voltage test plug which concerns on embodiment of this invention. 1 is a structural diagram of a voltage test plug according to an embodiment of the present invention. Operation | movement explanatory drawing at the time of inserting in the voltage test terminal in the state which connected the test line of the tester to the voltage test plug which concerns on embodiment of this invention. The block diagram of the conventional voltage test terminal and a voltage test plug. Operation | movement explanatory drawing when the conventional voltage test plug is inserted in the voltage test terminal at the time of voltage measurement. Operation | movement explanatory drawing when the conventional voltage test plug is inserted in a voltage test terminal, when testing an electric apparatus. The block diagram of the conventional voltage test terminal and voltage test plug when testing an electric apparatus. Operation | movement explanatory drawing at the time of inserting the conventional voltage test plug into a voltage test terminal, with a tester connected, when testing an electric apparatus.

  Embodiments of the present invention will be described below. FIG. 1 is a conceptual side view of a voltage test plug according to an embodiment of the present invention. FIG. 1 shows a case where the voltage test plug 21 is a three-pole plug, and has three plugs 21a, 21b, and 21c of white phase, red phase, and black phase (R phase, S phase, and T phase). ing. In the case of a four-pole plug, it has four plugs including a green phase (neutral phase). In the following description, a case of a three-pole plug will be described. Each plug 21a, 21b, 21c has an upper conductor 22a, 22b, 22c and a lower conductor 23a, 23b, 23c. The upper conductors 22a, 22b, 22c have fuses 28a, 28b, 28c in the terminal block 29, respectively. The upper conductors 22a, 22b, and 22c are connected to the outer terminals 24a, 24b, and 24c, and the lower conductors 23a, 23b, and 23c are connected to the inner terminals 25a, 25b, and 25c, respectively.

  The outer terminals 24a, 24b, and 24c are fixed on the shaft, and a test line is sandwiched between the movable outer knobs 30a, 30b, and 30c and the fixed outer terminals 24a, 24b, and 24c when performing a voltage test. Connect the tester with. Similarly, the inner terminals 25a, 25b, and 25c are also fixed on the shaft, and are connected between the movable inner knobs 31a, 31b, and 31c and the fixed inner terminals 25a, 25b, and 25c when measuring the voltage. One end of the piece is sandwiched, and the other end of the connection piece is sandwiched between the movable outer knobs 30a, 30b, 30c and the fixed outer terminals 24a, 24b, 24c. The voltage between each phase is measured by connecting between any two terminals of the outer terminals 24a, 24b, 24c, or between the connected connecting pieces.

  FIG. 2 is a structural diagram of the voltage test plug according to the embodiment of the present invention. FIG. 2A shows the position of the upper surface of the terminal block 29 and the fuses 28a and 28b at the mounting positions of the fuses 28a and 28b of the terminal block 29. FIG. 2B is a plan view after removal, and is an arrow view taken along line XX in FIG.

  The fuses 28a and 28b connected between the upper conductors 22a and 22b of the two plugs 21a and 21b of the three plugs 21a and 21b and 21c and the outer terminals 24a and 24b The fuse 28c connected between the upper conductor 22c of the plug 21c and the outer terminal 24c of the remaining plug 21c is disposed on the side surface of the terminal block 29. As a result, the fuses 28a, 28b, and 28c can be compactly attached to the terminal block 29 so that the fuses 28a, 28b, and 28c do not obstruct the insertion when the voltage test plug 21 is inserted into the voltage test terminal. ing. Further, since the fuses 28a, 28b, 28c are attached to the upper surface portion of the terminal block 29 and the side surface portion of the terminal block 29 instead of the mounting surface of the outer knobs 30a, 30b, 30c and the inner knobs 31a, 31b, 31c, There is no obstacle to the operation of the knobs 30a, 30b, 30c and the inner knobs 31a, 31b, 31c.

  Next, FIG. 3 is an operation explanatory diagram when the voltage test plug according to the embodiment of the present invention is inserted into the voltage test terminal with the test line of the tester being connected. Now, as shown in FIG. 3, the voltage test plug 21 is inserted to the positions of the first contacts 18 a, 18 b, and 18 c of the voltage test terminal 11 while the tester 27 is connected between the outer terminals 24 a and 24 b of the voltage test plug 21. Suppose that Then, the upper conductors 22a, 22b, 22c and the lower conductors 23a, 23b, 23c of the voltage test plug 21 are in contact with the first contacts 18a, 18b, 18c, and the third contacts 20a, 20b, 20c remain closed. Therefore, a short circuit indicated by an arrow is formed. That is, the transformer 16, which is an external power supply, the external power supply terminal 14a, the third contact 20a, the first contact 18a, the upper conductor 22a, the fuse 28a, the outer terminal 24a, the tester 27, the outer terminal 24b, the fuse 28b, and the upper conductor 22b. The short circuit between the first contact 18b, the third contact 20b, the external power supply terminal 14b, and the transformer 16 as an external power supply is formed, and a short circuit between phases occurs.

  In the embodiment of the present invention, fuses 28a, 28b, and 28c are provided between the upper conductors 22a, 22b, and 22c and the outer terminals 24a, 24b, and 24c. The capacities of the fuses 28a, 28b, and 28c are caused by the short circuit current of the short circuit between phases generated when the test line of the tester 27 is connected to the voltage test terminal 11, and the main body fuses 17a, 17b, and 17c on the external power supply side. The capacity that operates earlier is set. Accordingly, even if a short circuit between the fuses occurs, the fuses 28a and 28b operate before the main body fuses 17a and 17b, so that the main body fuses 17a and 17b are blown out, an erroneous display of the protection relay of the electric device 12 occurs, Or it can prevent causing malfunctions, such as an electric shock.

  As described above, the capacities of the fuses 28a, 28b, and 28c are set to capacities that operate before the main body fuses 17a, 17b, and 17c when a short-circuit current due to a short circuit between the external power supplies flows. 27 is set to a capacity that does not operate in a current range that flows in the case of a test voltage applied to the electrical device 12 in a normal test. Moreover, when a voltage higher than the test voltage applied in a normal test is applied, the capacitance is set to operate with the current flowing through the electric device 12. For example, a 1 A capacity fuse is used. Thereby, not only the short circuit between phases of the external power supply but also the electric device 12 can be protected even when an overvoltage is accidentally applied as a test voltage during the test.

  As described above, in the embodiment of the present invention, the fuses 28a, 28b, and 28c as safety devices are added to the voltage test plug 21, and the secondary circuit of the instrument transformer is short-circuited due to a locking operation or a handling error during work. Even so, a safety lock is applied so that the fuses 28a, 28b and 28c of the voltage test plug 21 operate instantaneously and the main fuses 17a, 17b and 17c of the instrument transformer do not operate. As a result, disconnection due to the operation of the main body fuses 17a, 17b, and 17c can be prevented, and maintenance is also facilitated.

DESCRIPTION OF SYMBOLS 11 ... Voltage test terminal, 12 ... Electric apparatus, 13 ... Electric apparatus connection terminal, 14 ... External power supply connection terminal, 15 ... Electric power system, 16 ... Transformer, 17 ... Main body fuse, 18 ... First contact, 19 ... Second Contact, 20 ... Third contact, 21 ... Voltage test plug, 22 ... Upper conductor, 23 ... Lower conductor, 24 ... Outer terminal, 25 ... Inner terminal, 26 ... Connection piece, 27 ... Tester, 28 ... Fuse, 29 ... Terminal block, 30 ... external picking, 31 ... internal picking

Claims (2)

A voltage having a first contact and a second contact between an electrical device connection terminal connected to the electrical device and an external power supply terminal connected to an external power supply, and a third contact for disconnecting the connection to the external power supply When testing the electrical device inserted into a test terminal, the third contact is opened to disconnect the electrical device from the external power source, and a tester is connected to the electrical device through the first contact and the second contact. A voltage test for connecting the electric device and the external power source through the first contact and the second contact with the third contact open when measuring a voltage applied to the electric device from a power source In the plug,
A lower conductor connected to the second contact via the first contact when inserted into the voltage test terminal;
When inserted into the voltage test terminal and in contact with the first contact, the lower contact and the first contact form a parallel circuit with the third contact while the third contact is closed. An upper conductor that opens the third contact while maintaining a connection with the first contact when contacted with the second contact via one contact;
An inner terminal for connecting one end of a connection piece for short-circuiting the upper conductor and the lower conductor when connected to the lower conductor and measuring the voltage;
An outer terminal connected to the upper conductor and connected to the other end of the connection piece for the voltage measurement and to connect the tester for testing the electrical device;
Connected between the upper conductor and the outer terminal, does not operate in the current range that flows in the case of a test voltage applied from the tester to the electrical device in a normal test, and connects the test line of the tester And a fuse that operates before the main body fuse on the external power supply side due to a short-circuit current between the phases of the external power supply through the tester that is generated when the voltage test terminal is inserted and removed. To voltage test plug.   The capacity of the fuse is a capacity that is smaller than a short-circuit current of a short circuit between phases of the external power supply and that operates with a current flowing through the electric device when a voltage larger than a test voltage applied in a normal test is applied. The voltage test plug according to claim 1.

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