JP3106977B2 - Circuit breaker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit breaker such as a circuit breaker for a wiring or an earth leakage breaker, and more particularly to a power supply means for an overcurrent trip section.

[0002]

2. Description of the Related Art A U-shaped part is formed in a main circuit conductor, and this U-shaped part is formed.
A circuit breaker in which a Hall element is disposed as a current detecting means for detecting the current of the main circuit conductor between both legs of the character-shaped portion is known (see Japanese Utility Model Publication No. 5-26683). This conventional circuit breaker will be described again with reference to FIG. 4, a fixed contact 10 and a movable contact 1 are provided between a power supply terminal 8 and a load terminal 9.
1, a flexible conductor 12 having one end connected to the movable contact 11, and a main circuit conductor 1 connected to the other end.
The terminals 8 and 9 have terminal screws 1.
The external conductors 3 are connected to each other.

The movable contact 11 is opened and closed by an operation unit 14, and the operation unit 14 includes an operation handle 15, a latch 16,
Latch receiver 17, toggle link 18, open / close spring 1
9 and the like. When the operating handle 15 is operated rightward in the illustrated ON state, the toggle link 18 is broken by the action of the opening / closing spring 19, the movable contact 11 is separated from the fixed contact 10, and the energization is cut off. When the current flowing through the main circuit conductor 1 is in an overcurrent state, a trip coil (not shown) is driven, and the latch receiver 1 is driven.
7, the latch 16 is released, and the latch 16 rotates leftward about the support pin 20 as a fulcrum. As a result, the toggle link 18 collapses, the movable contact 11 is opened, and the energization is cut off.

Here, the main circuit conductor 1 is formed in a U-shape in the middle, and the main circuit conductor 1 is placed between both legs of the U-shaped conductor.
Are arranged for each phase. The Hall element 3 is mounted on a printed circuit board 5 on which an electronic circuit of an overcurrent trip section is mounted. The main circuit conductor 1 and the printed circuit board 5 are housed in a case 21. Now, when the current I flows in the main circuit conductor 1, respectively flux phi ₁ to each part of the U-shaped conductor, phi _2, and phi ₃ Gaya
These occur in the direction of the mark BR> and act on the Hall element 3 in the same direction inside the U-shaped conductor. As a result, a voltage (Hall voltage) is generated in the Hall element 3 in a direction orthogonal to both the current and the magnetic field previously passed through the Hall element 3. Then, when the current I of the main circuit conductor 1 exceeds the rated current, the Hall voltage also exceeds a predetermined value, and a trip signal from the electronic circuit is applied to the above-mentioned trip coil (not shown) to cut off the current supply.

[0005]

In the conventional circuit breaker shown in FIG. 4, the power of the electronic circuit of the overcurrent trip portion is obtained from the main circuit conductor. In the case of a current transformer as a secondary conductor, if the current transformer for the power supply is arranged before and after the U-shaped portion of the main circuit conductor, the straight portion of the main circuit conductor becomes longer, and accordingly the longitudinal direction of the circuit breaker becomes longer. The dimensions increase. Further, the current transformer for power supply having such an arrangement has a problem that an output cannot be sufficiently obtained in a small area of the main circuit current. In view of the above, an object of the present invention is to provide a circuit breaker in which current detection means is arranged between both legs of a U-shaped main circuit conductor, and to compactly install a power transformer for an overcurrent tripping section. The idea is to increase the output.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a secondary coil disposed between both legs of a U-shaped main circuit conductor, and an iron core leg penetrating the secondary coil. And a core having a yoke surrounding both legs of the U-shaped portion. A current transformer for power supply is provided, and this current transformer for power supply supports the current detecting means. According to such means, the current transformer for power supply is installed in the U-shaped portion of the main circuit conductor integrally with the current detecting means, so that the required space is minimized, and both legs of the U-shaped portion are provided. The magnetic flux from the central part concentrates on the inner core leg, and the linear part of the main circuit conductor
Since twice the magnetic flux acts on the secondary coil, a sufficient output can be obtained even in a minute current region. As the current detecting means, an air-core current transformer can be used in addition to the Hall element.

[0007]

FIG. 1 is a longitudinal sectional view of a circuit breaker showing an embodiment of the present invention, FIG. 2 is an exploded perspective view of a power transformer, and FIG. 3 is a magnetic flux acting on a secondary coil. FIG. 4 is a side view of a current transformer for power supply for explaining the present invention. In each of these drawings, the same reference numerals are given to portions corresponding to the conventional example in FIG. 4, and description of substantially the same components is omitted. In FIG. 1, a main circuit conductor 1 of each phase is formed in a U-shape, and a power current transformer 2 for supplying power to an electronic circuit of an overcurrent trip section is provided in the U-shaped portion.
Is installed, and a Hall element 3 as a current detecting means is provided between the two legs 1a and 1b of the U-shaped part.
Is attached to the lower part of the case 4 in the case 4. A printed circuit board 5 on which an electronic circuit for outputting a trip signal based on the output voltage of the Hall element 3 which has detected a current flowing through the main circuit conductor 1 is installed vertically above the current transformer 2 for power supply, and its power supply terminal. The output line of the secondary coil 6 of the current transformer for power supply 2 is connected to the section.

As shown in FIG. 2, the power transformer 2 includes a secondary coil 6 and an iron core 7 composed of a pair of E-shaped iron cores. The secondary coil 6 is disposed between the two legs 1a and 1b of the U-shaped portion of the main circuit conductor 1 as shown in the figure. It has a penetrating iron leg 7a and yokes 7b, 7c surrounding both legs 1a, 1b. The left and right E-shaped iron cores are connected to each other by a connecting plate (not shown) which is fastened by screws between the right and left legs, and the current transformer 2 for the power supply has the iron core 7 formed on the side of the U-shaped portion of the main circuit conductor 1. Is supported by fitting into the groove 1c.

In FIG. 3, when a current I flows through the main circuit conductor 1 in the illustrated direction, a magnetic flux φ _{1 of the} current I flowing downward in the leg 1a and a current I flowing upward in the leg 1b in the diagram.
Interlink magnetic flux phi ₂ and the secondary coil 6 and a chain in the same direction, the secondary coil 6 larger in micro areas of the current I receives twice the magnetic flux of the main circuit conductor 1 of the U-shaped portion around the magnetic flux Generate output. On the other hand, in addition to the magnetic fluxes φ ₁ and φ ₂ , the magnetic flux φ _{3 of the} current flowing through the U-bent portion 1 c acts on the Hall element 3, and generates a Hall voltage according to the current I. Then, when the current I becomes an overcurrent state, the electronic circuit that has received the Hall voltage sends a trip signal to a trip coil (not shown) after a delay time determined by the magnitude of the current I, and opens the circuit breaker. In addition, besides the Hall element,
Air-core current transformers can also be used.

[0010]

According to the present invention, the current transformer for power supply of the overcurrent trip portion is installed in the U-shaped portion of the main circuit conductor.
Compared to the case where the circuit breaker is installed before and after that, the longitudinal size of the circuit breaker is reduced, and a magnetic flux that is twice the magnetic flux of the current flowing through the main circuit conductor acts on the secondary coil. You can get the output. Further, since the current detection element is integrally supported by the current transformer for power supply, the assembly configuration is simplified.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a circuit breaker showing an embodiment of the present invention.

FIG. 2 is an exploded perspective view of a power current transformer in FIG.

FIG. 3 is a side view illustrating a magnetic flux acting on a power transformer of FIG. 2;

FIG. 4 is a longitudinal sectional view of a circuit breaker showing a conventional example.

[Description of Signs] 1 Main circuit conductor 1a U-shaped leg 1b U-shaped leg 2 Current transformer for power supply 3 Hall element 5 Printed circuit board 6 Secondary coil 7 Iron core 7a Iron core 7b Yoke 7c Yoke 8 Power supply Side terminal 9 Load side terminal 10 Fixed contact 11 Movable contact 14 Operation unit 15 Operation handle

Continuation of front page (56) References JP-A-52-17675 (JP, A) JP-A-1-187909 (JP, A) JP-A-5-342970 (JP, A) , U) Fully open sho 61-203534 (JP, U) Fully open sho 62-163850 (JP, U) Really open sho 63-55525 (JP, U) Real open sho 63-137435 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01H 71/24 H01H 73/36

Claims (3)

(57) [Claims] 1. A circuit breaker in which a U-shaped part is formed in a main circuit conductor and current detecting means for detecting a current of the main circuit conductor is arranged between both legs of the U-shaped part. A current transformer for power supply, comprising a secondary coil disposed between both legs of the U-shaped portion, and an iron core having a core leg penetrating the secondary coil and a yoke surrounding both legs of the U-shaped portion. A circuit breaker, wherein the power supply current transformer supports the current detecting means. 2. The circuit breaker according to claim 1, wherein a Hall element is used as the current detecting means. 3. The circuit breaker according to claim 1, wherein an air current transformer is used as the current detecting means.