JPH1140039A - Electromagnetic repulsion current-limiter mechanism for circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the floating of a contact and allow a moving contact to separate from a fixed rapidly when an excessively large current is conducted by installing a current limiter spring composed of a coil-like compression spring between a spring seat and a spring catching surface in a compulsively energized state. SOLUTION: In the on-state of circuit breaker, a latch pin 15 is positioned below a latch hole 4a; this position is located lower than a line L connecting a spring catching surface 6a and a rotating axis of a moving contact 4; thereby, the energizing component force of a current limiting spring 17 acts in a direction to press the moving contact 4 against a fixed contact 2 so that the floating of the contact is suppressed. When an overcorrect started to flow and the electromagnetic repulsion between the moving contact 4 and the fixed contact 2 has become higher enough, the moving contact 4 is turned counterclockwise and hence, the latch pin 15 is lifted above the line L so that the moving contact 4 is separated from the fixed contact 2 rapidly. In addition, since the current limiting spring 17 is attached to the latch pin 15 through the spring seat 16 in a compressed state, the separation of the current limiting spring 17 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic repulsion current limiting mechanism for a circuit breaker.

[0002]

2. Description of the Related Art FIG.
FIG. 6 is a cross-sectional view showing a conventional circuit breaker provided with an electromagnetic repulsion current limiting mechanism disclosed in Japanese Patent Application Laid-Open Publication No. H10-209, FIG. FIG. 7 is a detailed sectional view showing the relationship between the movable contact and the holder in a state where the latch pin is on the stopper surface of the current limiting latch. In the figure, 1 is a circuit breaker body, 2
Is a fixed contact, 3 is a fixed contact, 4 is a movable contact, and 5 is a movable contact fixed to the tip of the movable contact 4. Reference numeral 6 denotes a holder which holds the movable contact 5 so as to be rotatable about a rotation shaft 7. Reference numeral 8 denotes an opening / closing mechanism which rotates the holder 6 via the toggle link 9 to separate the movable contact 5 from the fixed contact 3. 10 is a current limiting latch, 11 is a latch pin,
The current limiting latch 10 is rotatably held by the holder 6. 12
Is a current limiting spring, and a hook at one end of the pull spring is a holder 6.
The hook at the other end is engaged with the distal end of the movable arm of the current limiting latch 10 to urge the current limiting latch 10 clockwise about the latch pin 11 in the figure. Reference numeral 13 denotes a current limiting pin provided upright on the movable contact 4, and contacts the current limiting latch 10 to convert the biasing force of the current limiting spring 12 into a rotational force for the movable contact 4. The current limiting latch 10 has an engaging surface 10a, a current limiting surface 10b, and a stopper surface 10c corresponding to positions where the current limiting pin 13 comes into contact with a change in the position of the current limiting pin 13 as the movable contact 4 rotates. Each is provided. The engagement surface 10a, the current limiting surface 10b, and the stopper surface 10c are continuous surfaces, and the biasing force of the current limiting spring 12 due to the contact with the current limiting pin 13 causes the surface angle of the engagement surface 10a to be equal to the movable contact 4 The current limiting surface 10b is biased in the direction in which the movable contact 4 is separated from the fixed contact 2 by the angle of the current limiting surface 1b.
0b restricts excessive movement of the current limiting pin 13. Reference numeral 14 denotes a flexible conductor which is a current path to the movable contact 4.

Next, the operation of a conventional circuit breaker will be described. When the circuit breaker 1 is ON, that is, when the holder 6
Is located at a position where the fixed contact 3 and the movable contact 5 are brought into contact with each other.
At this time, the current limiting pin 13 is in contact with the engagement surface 10a, and the movable contact 4 presses the urging component of the current limiting spring 12 against the fixed contact 3 to obtain a contact pressure between the contacts. . When the amount of current supplied to the circuit breaker increases, the movable contact 4 and the fixed contact 2
During this time, an electromagnetic repulsive force acts to generate a force for rotating the movable contact 4 in the clockwise direction in the figure. This force lifts the movable contact 5 from the fixed contact 3 and generates an arc between the contacts. When the movable contact 4 rotates in the direction in which the movable contact 5 floats, the engagement surface 10a inclines the contact surface with the current limiting pin 13 so that the biasing force of the current limiting spring 12 increases. The contact is prevented from rising and the contact is prevented from being worn and welded by the arc. Therefore, the force for pressing the movable contact 4 against the fixed contact 3 needs to be applied to some extent.

Further, when an excessive current is applied, the electromagnetic repulsive force becomes larger due to the urging component of the current limiting spring 12, the movable contact 4 is rotated, and the current limiting pin 13 moves the engagement surface 10a. Beyond the boundary between the slip engagement surface 10a and the current limiting surface 10b, the current limiting surface 10
b, the biasing component of the current limiting spring 12 acts in a direction to separate the movable contact 4 from the fixed contact 2, and the fixed contact 3
The moving speed of the movable contact 5 is increased. For this reason, the arc is rapidly extended, the current is limited by the arc resistance in a short time, and the arc is induced and divided by the arc extinguishing device to extinguish the arc and interrupt the current.

[0005]

A conventional circuit breaker is:
The current limiting latch 10 and the current limiting spring 12 must be accommodated in the holder 6 in parallel, and the winding diameter of the current limiting spring 12 cannot be increased, so that it is difficult to obtain a large biasing force. there were.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and the winding diameter of the current limiting spring 12 is large and strong to prevent the floating of the contact point. The purpose of the present invention is to obtain an electromagnetic repulsion current limiting mechanism of a circuit breaker for rapidly opening the fixed contact 2 from the fixed contact 2.

[0007]

According to a first aspect of the present invention, there is provided an electromagnetic repulsion current limiting mechanism for a circuit breaker, comprising: a holder rotatably supporting a movable contact; A spring receiving surface provided on the holder, a latch hole having an elongated hole provided in the movable contact in the rotation direction thereof, a latch pin movably supported in the latch hole along the elongated hole, and a latch pin. And a current-limiting spring that is compression-inserted between the spring-receiving surface and the biasing force of the current-limiting spring presses the movable contact against the fixed contact when the latch pin is located on the contact side of the latch hole. When the contact side of the latch hole moves beyond the line connecting the center of rotation of the movable contact and the spring receiving surface due to the electromagnetic repulsive force, the biasing force of the current limiting spring moves the latch pin to the opposite side of the latch hole. To move the movable contact from the fixed contact In which was to work on.

According to a second aspect of the present invention, there is provided an electromagnetic repulsion current limiting mechanism for a circuit breaker, wherein a spring receiver is provided between a latch pin and a current limiting spring to prevent the current limiting spring from coming off.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a cross-sectional view of a circuit breaker according to a first embodiment of the present invention when the circuit breaker is on. FIG. FIG. 4 is a cross-sectional view of the circuit breaker of FIG. 1 when the movable contact is separated, and FIG. 4 is a perspective view of an assembled state of the current limiting spring according to Embodiment 1 of the present invention. In the figure, reference numerals 1 to 8 and 14 are the same as those described in the conventional apparatus. Reference numeral 4a denotes a latch hole, which is provided in a contact hole near the rotating shaft 7 of the movable contact 4 in a long hole shape in the rotating direction of the movable contact 4. Reference numeral 6a denotes a spring receiving surface provided on the holder 6, reference numeral 15 denotes a latch pin, reference numeral 16 denotes a spring receiver, and reference numeral 17 denotes a current limiting spring constituted by a coiled compression spring. The latch pin 15 is inserted into the latch hole 4a so as to be movable in the longitudinal direction of the latch hole 4a.
Spring supports 16 are rotatably mounted on both sides protruding from the movable contact 4. A current-limiting spring 17 is attached between the spring receiver 16 and the spring receiving surface 6a in a state where the current limiting spring 17 is compressed and urged. The spring receiver 16 is provided with a guide portion that enters the coil wheel of the current limiting spring 17, and this guide portion prevents the current limiting spring 17 from coming off when the current limiting spring 17 moves in a compressed state. , The urging force is effectively transmitted to the latch pin 15. Reference numeral 18 denotes a stopper pin.

In the ON state of the circuit breaker shown in FIG. 2, the latch pin 15 is located below the latch hole 4a, and this position is a line connecting the spring receiving surface 6a and the rotating shaft 7 of the movable contact 4. Since it is lower than L, the urging component of the current limiting spring 17 acts in the direction of pressing the movable contact 4 against the fixed contact 2 and suppresses the floating of the contact. Then, at the time of excessive current, when the electromagnetic repulsion between the movable contact 4 and the fixed contact 2 becomes stronger, the movable contact 4 is rotated counterclockwise in the drawing by this electromagnetic repulsion, and the latch pin 15 is moved from the line L. Become upward. In addition, the rotation of the movable contact 4 causes the latch hole 4 a
Of the latch pin 15 can be slid from the direction in which the latch pin 15 is restrained, so that the latch pin 15 moves upward through the latch hole 4a by the biasing force of the current-limiting spring 17, and the movable contact 4 is fixed to the fixed contact 2. The arc is quickly separated from the contacts, the arc between the contacts is rapidly extended, the current is limited by the arc resistance in a short time, and the arc is induced by the arc extinguishing device to be cut off and extinguished. The separated movable contact 4 is the stopper pin 1
8 is stopped. During this time, the overcurrent detection device rotates the holder 6 in the off direction via the opening / closing mechanism 8 to set the current interruption state. At this time, since the movable contact 4 is restrained by the stopper pin 18, the rotation of the holder 6 in the off direction moves the latch pin 15 below the latch hole 4 a to set the reset state.

[0011]

According to the electromagnetic repulsion current limiting mechanism of the circuit breaker constructed as described above, by using the current limiting spring 17 as a compression coil spring, the winding diameter of the current limiting spring 17 can be increased. Since the urging force of pressing the movable contact 4 against the fixed contact 3 by the current limiting spring 17 can be increased, the floating of the contact can be prevented, and the consumption and welding of the contact due to the arc can be suppressed.

Since the current limiting spring 17 is attached to the latch pin 15 via the spring receiver 16 in a compressed state, the guide portion of the spring receiver 16 is a current limiting spring when the current limiting spring 17 is displaced in a compressed state. 17 and the current limiting spring 1
7 can be effectively transmitted to the latch pin 15.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view when a circuit breaker according to Embodiment 1 of the present invention is on.

FIG. 2 is a cross-sectional view of the upper surface of the holder according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view of the circuit breaker according to Embodiment 1 of the present invention when the movable contact is opened.

FIG. 4 is an assembled perspective view of the current limiting spring according to Embodiment 1 of the present invention;

FIG. 5 is a cross-sectional view of a circuit breaker provided with a conventional electromagnetic repulsion current limiting mechanism.

FIG. 6 is a detailed sectional view showing a relationship between a movable contact and a holder in a state where a latch pin in a conventional circuit breaker is in contact with a support surface of a current limiting latch.

FIG. 7 is a detailed cross-sectional view showing a relationship between a movable contact and a holder in a state in which a latch pin in a conventional circuit breaker has a stopper surface of a current limiting latch.

[Explanation of symbols]

1 circuit breaker, 2 fixed contacts, 4 movable contacts, 4
a latch hole, 6 holder, 6a spring receiving surface, 7 rotating shaft, 8 opening / closing mechanism, 14 flexible conductor, 15 latch pin, 16 spring receiver, 17 current limiting spring, 18 stopper pin.

Claims (2)

[Claims] A movable contact that is rotatably supported by a holder and is in contact with a fixed contact; a spring receiving surface provided on the holder toward a center of rotation of the movable contact; A latch hole provided in the contact hole in the slot in the rotation direction thereof, a latch pin movably supported in the latch hole along the slot, and both sides of the latch pin projecting from the movable contact and A current limiting spring inserted between the spring contact surface and the spring contact surface, wherein when the movable contact comes into contact with the fixed contact, the latch pin is located on the contact side of the latch hole, and the current limiting spring is attached. The force component acts in the direction of pressing the movable contact against the fixed contact, and the contact side of the latch hole connects the rotation center of the movable contact to the spring receiving surface due to the electromagnetic repulsive force applied to the movable contact. The current-limiting spring when moving beyond the line Biasing force component electromagnetic repulsion current limiting mechanism of the circuit breaker, characterized in that acting in a direction separates from the fixed contact the movable contact is moved the latch pin to the opposite side of the latch hole. 2. The electromagnetic repulsion current limiting mechanism of a circuit breaker according to claim 1, wherein a spring receiver is provided between the latch pin and the current limiting spring to prevent detachment of the current limiting spring.