JP2005158751A - Circuit breaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit breaker whose short circuit breakdown performance is improved by rapidly exhausting an arc gas generated at arc-extinguishing action, while the size of the circuit breaker is maintained compact. <P>SOLUTION: The circuit breaker comprises: a case 110; an opening and closing unit 130 that opens and closes the circuit by the connection or separation of the fixed contact 138 with the movable contact 137; an arc grid 142 placed stacking a plurality thereof adjoining to the fixed and movable contacts; a first arc barrier 152 placed adjoining to the arc grid, and provided with a first exhaust hole 151 in the top part of the case for exhausting arc gas; a second arc barrier 160 disposed in an opening formed in the bottom part of the case adjoining to the fixed and movable contacts, and provided with a second exhaust hole 161 for exhausting the arc gas; and a door 170 for preventing entering dust into the case through the second exhaust hole by opening the second exhaust hole only when the arc is generated. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a circuit breaker, and more particularly, to a molded case circuit breaker that can improve arc extinguishing performance while maintaining a compact size.

  A circuit breaker is an electrical device that has a load on / off function and a line breaking function in the event of an accident current such as overload, short circuit, and ground fault, and effectively interrupts the circuit when a short circuit current occurs. The short-circuit breaking performance is the main function.

  In the case of a circuit breaker having a rated current of 100 A, verification of the short-circuit breaking performance is usually performed through a test in which an overcurrent of 2,500 to 10,000 A, which is about 25 to 100 times larger current, is interrupted twice.

  As a condition for improving the short-circuit breaking performance of the circuit breaker, the moment when an abnormal current such as overcurrent is cut off, that is, a stationary contact (movable contact on the power source side) The arc extinguishing ability to effectively suppress, extinguish or discharge the high-temperature arc and high-pressure arc gas generated at the moment of leaving, and minimize the time from the moment the movable contact leaves the fixed contact until the discharge gap disappears Therefore, there is a demand for rapidity to extinguish arcs as quickly as possible and durability of a circuit breaker that can sufficiently withstand high heat, pressure, and shock generated at the moment when the movable contact leaves the fixed contact.

  Recently, as the distribution board has been downsized, the circuit breaker built into the distribution board has also been downsized, but in this way, the internal space of the circuit breaker has gradually become smaller. The capacity of the loader connected to the fixed contact is increasing, and for this reason, it is required to obtain a high short-circuit breaking performance with a circuit breaker of the same size.

  The structure of the circuit breaker is mainly composed of a detection unit, a switching unit, and an arc extinguishing unit.

  The detection unit senses an abnormal current and activates the switching unit, and the switching unit is operated by the detection unit to move the movable contact to interrupt the line, or manually move the movable contact. The arc-extinguishing unit extinguishes and discharges the arc and high-pressure arc gas generated from the contact of the power source side fixed contact when an abnormal current occurs.

  In addition, the circuit breaker is provided with an auxiliary device so that the current state of each component attached to the distribution board and the distribution board can be monitored and controlled in a remote control room.

  The circuit breaker's ON state is the state where the movable contactor connects the power supply side fixed contactor and the load side fixed contactor to connect the line. The circuit breaker's OFF state is an artificial state The switching unit is activated and the movable contact is separated from the power-side fixed contact and the load-side fixed contact so that the track is disconnected. The circuit breaker trip state is detected. In this state, the unit detects an abnormal current and automatically operates the open / close unit so that the movable contactor interrupts the power source side fixed contactor and the load side fixed contactor.

  7 is a perspective view showing the structure of a conventional circuit breaker, FIG. 8 is a plan view showing the conventional circuit breaker, FIG. 9 is a vertical sectional view taken along the line II of FIG. A) shows the on state of the circuit breaker, and FIG. 9B shows the off state of the circuit breaker.

  As shown in the drawing, a conventional circuit breaker 1 includes a detection unit 3 that senses an overcurrent inside a main body 2 and a movable contact 4 that is connected to the power source side fixed contact by the detection unit 3 or by manual operation. 5 and an open / close unit 7 that selectively cuts off the load side stationary contact 6 and an arc extinguishing and exhausting arc generated from the contact 5a of the power source side stationary contact 5 and the high-pressure arc gas when an abnormal current occurs. Arc unit 8.

  In the detection unit 3, a trip coil 10 is wound around the outer peripheral surface of an ODP (Oil Dash Port) cylinder 9. In the opening / closing unit 7, a yoke 11 that supports the ODP cylinder 9 is vertically installed inside the main body 2, and an armature 12 is rotatable about a rotating portion 12 a at the upper portion of the yoke 11. The armature 12 is configured to press the trip bar 13 while rotating. A link portion 14 is constrained to the trip bar 13, and a handle 15 is installed on the upper portion of the link portion 14 so as to be rotatable about a hinge 15 a. A cradle 16 for guiding the ascending / descending movement of the link unit 14 is installed on the side surface of the link unit 14, and a cross bar 17 is installed vertically below the link unit 14 so as to be movable vertically. The movable contact 4 connects the power-side fixed contact 5 and the load-side fixed contact 6 to the lower portion of the body 17 and presses the movable contact 4 upward on the bottom surface of the main body 2. A spring 18 is installed.

  In the arc extinguishing unit 8, the contact 5a of the power source side fixed contact 5 and the contact 4a of the movable contact 4 are located inside the arc extinguishing chamber 8a, and the arc extinguishing chamber 8a includes a plurality of An arc extinguisher 8b is installed. A plurality of exhaust holes 2 a for discharging arc gas are formed in the upper part of the main body 2.

  Unexplained code S1 indicates a power supply side fixing screw for fixing the power supply side terminal, and S2 indicates a load side fixing screw for fixing the load side terminal.

  In the conventional circuit breaker 1 configured in this way, as shown in FIG. 9A, when a normal current flows on the line, between the power-side fixed contact 5 and the load-side fixed contact 6. Are connected by the movable contact 4 so that a current flows from the power source side fixed contact 5 to the load side fixed contact 6 side.

  However, when an abnormal current flows on the line and the circuit breaker 1 is in a trip state, the movable contact between the power-side fixed contact 5 and the load-side fixed contact 6 as shown in FIG. 9B. 4 is cut off, so that no current flows from the power source side fixed contact 5 to the load side fixed contact 6 side.

  That is, when an abnormal current flows on the line, the detection unit 3 senses the abnormal current and automatically operates the switching unit 7.

  By the operation of the opening / closing unit 7 and the spring 18, the movable contact 4 shuts off the power-side fixed contact 5 and the load-side fixed contact 6.

  When the contact 4a of the movable contact 4 starts to be separated from the contact 5a of the power-side fixed contact 5, and the respective contacts 4a and 5a are separated from each other by a predetermined distance, the contact 4a is generated from the contact 5a of the power-side fixed contact 5. The arc is extinguished by the arc extinguishing unit 8. The arc gas generated at this time is discharged to the outside of the main body 2 through the exhaust hole 2a.

  Currently, the space for installing the arc extinguishing unit 8 in the main body 2 of the circuit breaker is limited due to the trend toward miniaturization of the circuit breaker. Therefore, in the conventional circuit breaker, in order to reduce the horizontal installation length of the arc extinguishing unit, the arc grid (ARC GRID), the arc barrier, and the arc exhaust port are arranged in the vertical direction within a short horizontal length. It has come to have a structure of stacking.

  Therefore, such a conventional circuit breaker has a structure in which the arc gas generated when the fixed contact and the movable contact located at the lower part inside the main body are separated is guided and discharged to the upper side of the main body 2. Therefore, the exhaust port is far away from the lower position of the main body 2 where the arc is generated, and there is a problem that the arc gas cannot be discharged quickly.

  In addition, when the size of the exhaust hole is increased in order to quickly discharge the arc gas to the outside of the circuit breaker, dust and foreign substances enter the circuit breaker and the performance of the circuit breaker deteriorates. Therefore, in the conventional circuit breaker, the exhaust hole design is greatly restricted.

  The present invention has been made in view of such conventional problems, and quickly discharges arc gas generated during arc extinguishing operation to the outside of the case while maintaining a compact circuit breaker size. Therefore, it aims at providing the circuit breaker which can improve a short circuit interruption | blocking performance.

  An object of the present invention is to provide a case, a fixed contact and a movable contact installed in the case, and a power source and a load by contact or separation between the fixed contact and the movable contact. An open / close unit that opens and closes a circuit between the arc grid, a plurality of arc grids that are stacked and installed adjacent to the fixed contact and the movable contact of the open / close unit, and the fixed contact and the movable contact of the arc grid A first arc barrier that is installed adjacent to the opposite side of the surface facing the child, prevents arcs, and has a first exhaust port at an upper portion for exhausting arc gas from an upper position of the case; A second exhaust port is provided in the opening formed in the lower portion of the case so as to be adjacent to the fixed contact and the movable contact of the opening / closing unit, and includes a second exhaust port for discharging arc gas. The case through which the arc barrier and the second exhaust port of the second arc barrier are opened when an arc is generated, the outer surface of the second arc barrier is closed when no arc is generated, and the second exhaust port is passed through. This can be achieved by providing a circuit breaker according to the present invention comprising a door that prevents dust from entering the interior.

  Another object of the present invention is to provide a stationary contact having a communication opening that communicates with the second exhaust port so that the generated arc gas is exhausted through the second exhaust port of the second arc barrier. Can be achieved by providing a circuit breaker according to the present invention.

  Another object of the present invention is to install the arc gas on the stationary contact so as to guide the generated arc gas to be discharged through the second exhaust port via the communication opening of the stationary contact. This can be achieved by providing a circuit breaker according to the present invention further comprising an arc runner.

  In the circuit breaker according to the present invention, the arc gas is straightened through the operation of the second exhaust mechanism and the second exhaust port 161 while maintaining the installation space of the existing arc extinguishing and arc gas exhaust device for the compact circuit breaker. Thus, the discharge performance can be improved while maintaining a compact physical dimension without increasing the size and length of the circuit breaker.

  Further, in the circuit breaker of the present invention, dust and foreign substances do not flow into the case 110, so that there is no great restriction on the design of the exhaust port.

  Hereinafter, preferred embodiments of a circuit breaker according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a perspective view showing a structure of a circuit breaker according to the present invention, FIG. 2 is a perspective view showing a second exhaust mechanism of the circuit breaker according to the present invention, and FIG. 3 is a left side showing the circuit breaker according to the present invention. 4 is a plan view showing a circuit breaker according to the present invention, FIG. 5 is a longitudinal sectional view taken along line II-II in FIG. 4, and FIG. 5 (A) is a diagram showing an on state of the circuit breaker. 5 (B) shows an off state of the circuit breaker, and FIG. 6 is a perspective view showing a power source side fixed contactor of the circuit breaker according to the present invention.

  As shown in FIG. 5A, a circuit breaker 100 according to the present invention includes a detection unit 120 for sensing an abnormal current, a movable contact 137, and a fixed contact 138 in a case 110, and the detection unit. 120 or the manual operation by the operation handle, the open / close unit 130 that moves the movable contact 137 away from the power supply side fixed contact 138, and the power supply side that is separated when an accident current such as a short circuit current or a ground fault current occurs. And an arc extinguishing unit 140 that extinguishes and discharges an arc and high-pressure arc gas generated between the contact 138a of the fixed contact 138 and the contact 137a of the movable contact 137.

  In the arc extinguishing unit 140, a contact point 138 a of the power source side fixed contact 138 and a contact point 137 a of the movable contact 137 are located inside the arc extinguishing chamber 141, and the arc extinguishing chamber 141 includes a plurality of arcs. A grid 142 is installed.

  Further, as a feature of the present invention, in addition to the arc gas first exhaust mechanism installed at the upper part of the case 110 so that the arc gas can be quickly discharged to the outside of the case 110, A second exhaust mechanism is provided at the bottom.

  As shown in FIG. 5A, the first exhaust mechanism includes an arc grid 142 in which a plurality of layers are vertically stacked so as to be adjacent to the fixed contact 138 and the movable contact 137 of the opening / closing unit 130. The arc grid 142 is installed to be adjacent to the opposite side of the surface facing the fixed contact and the movable contact so as to block the arc, and has a first exhaust port 151 in the upper part to supply the arc gas to the case 110. A first arc barrier 152 for exhausting air from an upper position of the first arc barrier 152.

  As shown in FIGS. 2 and 5A and 5B, the second exhaust mechanism is disposed below the case 110 so as to be adjacent to the fixed contact 138 and the movable contact 137 of the opening / closing unit 130. A second arc barrier 160 provided with a second exhaust port 161 for discharging arc gas, which is installed in the opening to be formed, and the second exhaust port 161 of the second arc barrier 160 when the arc is generated, opens the arc. A door 170 that closes the outer surface of the second arc barrier 160 to prevent the intrusion of dust into the case 110 through the second exhaust port 161 when there is no occurrence.

  The door 170 is preferably made of an elastic resin material such as plastic.

  Hereinafter, the configuration of the second exhaust mechanism according to the present invention will be described in more detail with reference to FIG.

  When the present invention is applied to a three-phase AC circuit breaker, as shown in FIG. 2, three support protrusions 171 correspond to the three phases for supporting the door 170 on the lower outer surface of the case 110. The support projection 171 supports the second arc barrier 160 together by protruding through a hole h provided in the lower portion of the second arc barrier 160. A support hole 172 is formed in the lower portion of the door 170 so that the support protrusion 171 is inserted, and a pair of support protrusions 173 are formed on both upper side surfaces of the opening of the case 110. Corresponding support grooves 174 are formed on both side surfaces of the upper portion of the door 170 so that the 173 engages. The engagement maintaining force between the support protrusion 173 and the support groove 174 does not become larger than the arc gas pressure at the time of arc generation. When the arc is generated, the door 170 is opened by the arc gas pressure, and no arc is generated. When the current is applied, adjustment can be made so that the door 170 is closed to prevent dust from entering the case 110.

  As shown in FIG. 6, the stationary contact 138 communicates with the second exhaust port 161 to guide the arc gas so that the generated arc gas is exhausted through the second exhaust port 161 of the second arc barrier 160. A communication opening 138b is provided. More specifically, the stationary contact 138 is a metal member made of, for example, brass having a substantially “U” -shaped conductivity, and a lower horizontal portion 138e to which a contact 138a is attached at one end portion; A vertical portion 138f consisting of two vertical pillars extending vertically from the other end portion of the lower horizontal portion 138e and spaced apart from each other so as to form a communication opening 138b, and a contact point 138a attached to the vertical portion 138f. An upper horizontal portion 138b that is bent and extended toward one end portion of the lower horizontal portion 138e. The upper horizontal portion 138b also functions as a terminal to which a power supply side electric wire is connected. However, in order to fix the position in a state where the power supply side electric wire is connected to the upper horizontal portion 138b, the upper horizontal portion 138b is arranged on the upper horizontal portion 138b. Is provided with a screw hole 138h having an inner peripheral surface screwed into the terminal screw S1.

  When an accident current occurs, an arc and arc gas generated between the contact 137a of the movable contact 137 and the contact 138a of the fixed contact 138 are passed through the communication opening 138b of the fixed contact 138 and the second exhaust. An arc runner 138 c is installed on the stationary contact 138 to guide the discharge through the mouth 161.

  Unexplained symbol S2 is a load side terminal screw for fixedly connecting the load side electric wire, and C is a metal cable (also called a shunt) for connecting the movable contact and the load side fixed contact. Indicates.

  In the circuit breaker 100 according to the present invention configured as described above, when a normal current flows on the line, the movable contact 137 is connected between the power-side fixed contact 138 and the load-side fixed contact 139. Then, a current flows from the power source side fixed contact 138 to the load side fixed contact 139 side.

  However, when an accident current such as a short circuit current or a ground fault current flows on the circuit between the power source and the load, the detection unit 120 detects this and operates the open / close unit 130, thereby The movable contact 137 is separated from the power source side fixed contact 138a. Therefore, the current flowing from the power source side fixed contact 138 to the load side fixed contact 139 is cut off, and this state is called a trip state of the circuit breaker.

  That is, when an abnormal current flows on the line, the detection unit 120 detects the abnormal current and automatically operates the switching unit 130.

  The movable contact 137 is raised by the operation of the opening / closing unit 130 and the spring E, and the electric circuit between the power-side fixed contact 138 and the load-side fixed contact 139 is interrupted.

  When the contact 137a of the movable contact 137 is separated from the contact 138a of the power source side fixed contact 138, and each contact 137a, 138a is separated by a predetermined distance, the arc generated from the contact 137a, 138a is caused by the arc extinguishing unit 140. Disappear. That is, a part of the arc and arc gas generated at this time is discharged to the outside of the case 110 through the first exhaust port 151 of the first exhaust mechanism, and the remainder of the arc gas is connected to the communication opening 138b of the power source side fixed contact 138 and the first outlet. It is discharged to the outside of the case 110 through the second exhaust port 161 of the two exhaust mechanism. The arc runner 138c serves to smoothly guide the initial arc.

  In the circuit breaker according to the present invention, as a configuration for discharging the arc gas, in addition to the existing first exhaust mechanism, a second exhaust mechanism capable of quickly discharging the arc and the arc gas by linearly guiding is provided. Therefore, the arc gas is quickly discharged to the outside of the case 110.

  Further, the door 170 closes the second exhaust port 161 of the second exhaust mechanism when the arc gas is not discharged, but when the arc gas is discharged, the door 170 is bent to the outside of the case 110 by the pressure of the arc gas. After opening the second exhaust port 161 of the second exhaust mechanism and discharging the arc gas, the second exhaust port 161 returns to the original position and the second exhaust port 161 is closed again.

  In the above embodiment, the case where the second exhaust mechanism according to the present invention is applied only to the power source side fixed contact side has been described. However, the double contact type movable contact, and thereby the power source and the load side fixed contact In the case of a circuit breaker in which two arc extinguishing units are provided adjacent to each other, the second exhaust mechanism can be additionally installed so as to be adjacent to the load side fixed contact. Moreover, in the above embodiment, the description has been given of the case where the communication opening 138b and the arc runner 138c communicating with the second exhaust port 161 are provided only in the power source side fixed contact 138. As described above, the double contact type movable contact is provided. In addition, in the case of a circuit breaker in which two arc extinguishing units are provided adjacent to the power source and the load-side fixed contact thereby, the communication opening 138b and the arc runner 138c communicating with the second exhaust port 161 are Various modifications can be made, for example, it can be provided on the side fixed contact 139.

It is a perspective view which shows the structure of the circuit breaker by this invention. It is a perspective view which shows the 2nd exhaustion mechanism of the circuit breaker by this invention. It is a left view which shows the circuit breaker by this invention. It is a top view which shows the circuit breaker by this invention. It is the II-II longitudinal cross-sectional view of FIG. 4 which shows the ON state of a circuit breaker. It is the II-II longitudinal cross-sectional view of FIG. 4 which shows the OFF state of a circuit breaker. It is a perspective view which shows the power supply side stationary contact of the circuit breaker by this invention. It is a perspective view which shows the structure of the conventional circuit breaker. It is a top view of the conventional circuit breaker of FIG. It is II longitudinal cross-sectional view of FIG. 8 which shows the ON state of a circuit breaker. It is the II longitudinal cross-sectional view of FIG. 8 which shows the OFF state of a circuit breaker. It is a left view of the conventional circuit breaker of FIG. It is a perspective view which shows the power supply side stationary contact of the conventional circuit breaker.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Circuit breaker 110 Case 120 Detection unit 130 Switching unit 137 Movable contact 137a Contact 138 Power supply side fixed contact 139 Load side fixed contact 140 Arc extinguishing unit 141 Arc extinguishing chamber 142 Arc grid 150 First exhaust mechanism 151 Exhaust port 160 Second exhaust mechanism 170 Door 171 Fixed projection 172 Support hole 173 Support projection 174 Support groove 138b Communication opening 138c Arc runner

Claims (4)

One case,
An opening / closing unit that is installed in the case and includes a stationary contact and a movable contact, and opens and closes a circuit between a power source and a load by contact or separation between the stationary contact and the movable contact;
An arc grid in which a plurality are stacked and installed so as to be adjacent to the fixed contact and the movable contact of the open / close unit;
The arc grid is installed so as to be adjacent to the opposite side of the surface facing the fixed contact and the movable contact of the arc grid. A first arc barrier for exhausting
A second arc barrier provided with a second exhaust port for discharging arc gas, installed in an opening formed in a lower portion of the case so as to be adjacent to the fixed contact and the movable contact of the open / close unit;
When the arc is generated, the second exhaust port of the second arc barrier is opened, and when no arc is generated, the outer surface of the second arc barrier is closed, and dust enters the case through the second exhaust port. A door to prevent the intrusion of,
A circuit breaker comprising:   The stationary contact has a communication opening communicating with the second exhaust port in order to induce the arc gas so that the generated arc gas is exhausted through the second exhaust port of the second arc barrier. The circuit breaker according to claim 1.   An arc runner installed on the stationary contact for guiding the generated arc gas to be discharged through the second exhaust port via the communication opening of the stationary contact; The circuit breaker according to claim 1 or 2, characterized by the above.   The circuit breaker according to claim 1, wherein the door is made of an elastic material.

Images