JPS6136051Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a circuit breaker that effectively extinguishes the arc that occurs when the circuit breaks.

In conventional circuit breakers, when an overcurrent flows between a fixed contact and a movable contact, the movable contact separates from the fixed contact, as is well known. An arc is generated during this opening, and this arc is caused by a distorted magnetic field generated by the arc extinguishing plate made of a magnetic material with a U-shaped or V-shaped notch that constitutes the arc extinguishing chamber. It receives a driving force in the direction of the rear end and intersects with the arc extinguishing plate. Therefore, the arc is cut into pieces by a plurality of arc extinguishing plates, cooled and extinguished.

However, as the rupture current increases, it becomes difficult to extinguish the arc that occurs during the rupture using only the arc extinguishing chamber used in the conventional circuit breaker. That is, the arc energy increases as the break current increases, and the internal pressure within the casing of the circuit breaker generated by the arc increases. As a result, the casing made of insulating material is destroyed, resulting in a breakdown. Even if the strength of the casing is sufficient, as the arc energy increases, the amount of arc emitted from the exhaust port provided in the casing will increase and There was a risk of a ground fault, phase-to-phase short circuit, or power supply short circuit. Furthermore, due to the rise in the temperature of the gas within the housing, the vicinity of the fixed and movable contacts, the vicinity of the arc extinguishing chamber, the opening/closing mechanism, and the arc flow path may become carbonized or have molten matter adhered to them, causing damage. This lowers the insulation resistance and makes it impossible to completely break the circuit. Furthermore, the arc energy significantly wears out the fixed contacts and the movable contacts, resulting in incomplete conduction between the contacts when the contacts are turned on again after the shearing is complete.

This idea was made to eliminate the drawbacks of the conventional method.A blowout coil was installed on the side of the arc extinguishing chamber with a separator in between, and by passing current through the blowout coil, the arc was extinguished. By driving the blowout coil toward the back of the arc chamber (downward in the figure) and by providing a separator, the blowout coil is prevented from being damaged by the arc. An embodiment of this invention will be described below with reference to the drawings.

FIG. 1 is a side sectional view showing an embodiment of the circuit breaker and circuit breaker according to this invention. 2 is a perspective view of the separator of FIG. 1; FIG. FIG. 3 is a side sectional view showing a state in which the separator is removed from FIG. 1. In FIGS. 1 to 3, a housing 1 is made of an insulating material, houses an opening/closing mechanism, and is provided with an outlet 101. As shown in FIGS. The fixed conductor 2 is fixed to the housing 1, a fixed contact 3 is attached to one end, and an external conductor (not shown) is connected to the other end. The movable contact 4 is attached to one end of the movable element 5 opposite to the fixed contact 3. The operating handle 6 opens and closes the movable contact 4 with respect to the fixed contact 3, and an operating spring 7 is stretched between the operating handle 6 and the movable element 5.
The blowout coil 8 is made of a flexible conductor, is connected between one end of the movable element 5 and the bimetal 9, and is provided at the side of the arc extinguishing chamber 18, which will be described later, so as to surround the arc extinguishing chamber 18. The terminal board 10 is fixed to the housing 1, one end is connected to the other end of the bimetal 9,
The other end is connected to an external conductor (not shown). The tripping lever 11 is rotatably supported by a shaft 12, and one end of an operating spring 7 is stretched together with the operating handle 6.
A is engaged with the actuating plate 13 when the movable contact 3 and the fixed contact 4 are closed. The actuating plate 13 is attracted in the direction of arrow A against the force of the spring 15 when the electromagnet 14 is energized, thereby disengaging the engagement between the one end 11a of the tripping lever 11 and the actuating plate 13. The adjusting screw 16 is attached to the terminal plate 10 by a nut 17 and is used to adjust the degree of curvature of the bimetal 9. The arc extinguishing chamber 18 extinguishes the arc generated when the movable contact 4 separates from the fixed contact 3, and is composed of a support frame 181 and an arc extinguishing chamber 182. The separating plate 19 separates the arc extinguishing chamber 18 from the blowout coil 8, and is made of an insulating material.
Bolts 20 are used to attach the separator 19 to the housing 1.

Next, this operation will be explained. Now, when an overcurrent such as a short circuit current occurs in the circuit, this current flows through the fixed conductor 2 → fixed contact 3 → movable contact 4 → mover 5 → blowout coil 8 → bimetal 9 → terminal board 10. The electromagnet 14 is excited by this overcurrent, attracts the actuation plate 13 in the direction of the arrow, and releases the engagement between the one end 11a of the tripping lever 11 and the actuation plate 13. Therefore, the tripping lever 11 rotates clockwise about the shaft 12 to change the tension position of the operating spring 7 relative to the movable element 5. When the tension position of the operating spring 7 changes and passes the dead point with respect to the movable element 5, the movable element 5 rotates counterclockwise and the movable contact 4
is separated from the fixed contact 3. This separation generates an arc, which is extinguished in the arc extinguishing chamber 18. In this case, as described below, the arc is driven toward the back of the arc extinguishing chamber 18 by the action of the magnetic flux generated in the blowout coil 8, and is extinguished well. Note that the surface of the blowout coil 8 is subjected to electrical insulation treatment.

Next, the blowout coil 8 and this and the arc extinguishing chamber 1
The effect of installing the separating plate 19 that separates the That is, the winding direction of the blowout coil 8 is determined by the arc current I generated between the fixed contact 3 and the movable contact 4 and the magnetic field B generated by the blowout coil 8 and crossing the arc when the current is interrupted. The direction of the vector product I×B is arc extinguishing chamber 1
It is wound so that it faces towards the back of 8. Therefore,
The arc generated between the fixed contact 3 and the movable contact 4 passes through the insulating separator 19 and receives a driving force in the direction of the arc extinguishing chamber 18 due to the magnetic field created by the blowout coil 8. . Furthermore, when a large fault current or the like attempts to flow through a circuit or disconnector, the movable contact 4 not only receives a repulsive force due to current concentration, but also the mover 5 receives an electromagnetic repulsive force due to the blowout coil 8. A faster dissociation rate can be obtained compared to conventional methods. In other words, when a large fault current is about to flow, the blowout coil 8 causes the mover 5 to open more quickly, and the arc generated by this opening is driven toward the back of the arc extinguishing chamber 18 more quickly. , arc extinguishing plate 182
The arc is divided and cooled to extinguish the arc. Also at this time,
Since the blowout coil 8 is isolated from the arc extinguishing chamber 18 by a separator 19, it cannot be damaged by arcing.

Therefore, the arc voltage generated between the movable contact 3 and the fixed contact 4 becomes higher, and as this arc propagation pressure increases, the passing fault current decreases and the shearing time also decreases. In other words, the current limiting action of the low voltage circuit or disconnector is effectively achieved. In this way, the so-called arc energy, which is obtained by time-integrating the product of passing current and arc voltage during the arc period, is much smaller than in the conventional case. Therefore, the following matters directly related to the magnitude of arc energy are improved. That is, (a) the casing 1, which is a molded product that suppresses the increase in internal pressure when a large current is interrupted, will not be destroyed. (b) Fixed contact 3
The amount of contact wear between the movable contact 4 and the movable contact 4 is reduced, so that it can withstand more repeated use. (c) The amount of sparks emitted to the outside from the discharge port 101 is reduced, and accidents inside the panel caused by the amount of sparks emitted are eliminated. (d) The degree of melting and carbonization of the movable contact 3, fixed contact 4, arc extinguishing chamber 18, and other parts exposed to the arc is reduced, and the megohm between the power source and the load is improved. (E) Since the arc is well extinguished, secondary disasters such as electric shock and fire accidents do not occur. (f) Since the separator 19 is provided, the blowout coil 8 is not damaged by arc. In the above embodiment, the number of windings of the blowout coil 8 is one, but it goes without saying that the number of windings of the blowout coil 8 may be multiple times depending on the magnitude of the required driving force of the arc.

As described above, according to this invention, current can be turned on and off many times safely and reliably.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing an embodiment of the circuit breaker and circuit breaker according to this invention. 2 is a perspective view of the separator of FIG. 1; FIG. FIG. 3 is a side sectional view showing a state in which the separator is removed from FIG. 1. In the figures, the same parts in each figure are given the same symbols, 1 is the housing, 2 is the fixed conductor, 3 is the fixed contact, 4 is the movable contact, 5 is the mover, 8 is the blowout coil, and 10 is the The terminal board, 18 is an arc extinguishing chamber, and 19 is a separating plate.

Claims (1)

[Scope of utility model registration request] a fixed conductor fixed to a housing and having a fixed contact at one end; a movable element having a movable contact at one end opposite to the fixed contact; an arc chamber, a flexible conductor having one end attached to the mover, the other end connected to a terminal board for connecting an external conductor, and surrounding the arc extinguishing chamber at a side of the arc chamber; and a separator detachably attached to the housing to isolate the blowout coil and the arc extinguishing chamber, and by passing a current through the blowout coil,
A circuit breaker characterized in that the arc is driven toward the back of the arc extinguishing chamber.