JP3143258B2 - Circuit breaker with adjustable opening time - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a circuit breaker.

[0002]

2. Description of the Related Art A conventional circuit breaker has a drive unit including an electromagnetic coil having a hollow portion (hereinafter referred to as a trip coil) and a movable iron core movably supported inside the hollow portion. ing. The movable core of the drive unit is connected to a known trip device via a predetermined connection mechanism, and the trip device is operated by movement of the movable core. When the tripping device operates, the lever locked by the tripping device moves, and the movable contact connected to the lever is separated from the fixed contact. In the circuit breaker having such a configuration, the time from when the trip coil is energized to when the movable contact separates from the fixed contact is referred to as “opening time”. The opening time is affected by the mass of the movable core, the "play" in the connecting mechanism and the mounting portion of the movable contact, and is usually a value unique to each circuit breaker. When using a circuit breaker, it is necessary to select a circuit breaker having an opening time suitable for the state of use. For example, if the opening time is too short, the breaking energy generated at the time of breaking will increase. For this reason, a large amount of heat is generated at the contact portion between the fixed contact and the movable contact, and these parts are rapidly worn.
The reason is as follows. The breaker is opened when the current abnormally increases due to a surge current or the like. In this case, a large current flows immediately after the occurrence of the surge. If the circuit breaker is opened in a state where the large current is flowing, a large arc current flows at the time of breaking, and the breaking energy increases. However, if the current is slightly reduced after a predetermined time after the occurrence of the surge and the current is slightly reduced, the breaking energy can be prevented by preventing the temperature rise of the contact without increasing the breaking energy so much.
Generally, five-cycle breakers and three-cycle breakers are known as standards for circuit breakers. The five-cycle circuit breaker completes the shutoff five cycles after the trip coil is energized, and the three-cycle breaker completes the shutoff after three cycles. Since the time point of the completion of the interruption is defined as the time point at which the arc disappears, the interruption time defined by the time from the start of energization to the arc disappearance is the sum of the opening time and the arc time.

[0003]

Conventionally, there is no compatibility between circuit breakers having different standards as described above. For example, when a circuit breaker with a standard of 3 cycles is used in a system with a standard of 5 cycles, It was necessary to use a control device to extend the shut-off time. An object of the present invention is to provide a circuit breaker capable of arbitrarily changing the opening time.

[0004]

The circuit breaker of the present invention has a movable core connected to the movable contact of a circuit breaker having a fixed contact and a movable contact, and the movable contact is connected to the fixed contact. A coil is connected in series to a trip coil that gives the movable core a dissociating action from the armature.

[0005]

The time constant of the trip coil increases due to the inductance of the coil connected in series with the trip coil, so that the operation of the movable iron core is delayed.

[0006]

【Example】

[Embodiment 1] FIG. 1 shows the configuration of a circuit breaker according to a first embodiment of the present invention. In FIG. 1, a trip coil 1 shown in a sectional view has a hollow portion 1A, in which a movable core 2 is supported so as to be movable in the direction of arrow 1B. The movable iron core 2 is connected to a trip arm 4 via a connecting rod 3. The trip arm 4 is rotatably supported by a frame (not shown) on the shaft 4A, and is urged upward in the figure by a pull spring 4D. A latch 4B is provided at the right end of the trip arm 4 in the drawing. When the circuit breaker is closed, the latch 4B is engaged with one end of an L-shaped lever 5 rotatably supported by a frame on a shaft 5A. This latch 4B is moved by an arrow 5B
The lever 5 which is about to rotate in the direction is locked. The other end of the lever 5 is connected to a movable contact 8 via a connecting rod 7. The movable contact 8 is rotatably supported by a frame on a shaft 8A, and a contact 8B is provided at an end. The fixed contact 9 having a contact 9A that contacts the contact 8B is fixed to the frame via a predetermined insulator. One terminal 1C of trip coil 1 is connected to one terminal of another coil 15 having hollow portion 15A, and the other terminal of coil 15 is connected to one terminal 10A of DC power supply 10. The other terminal 1D of the trip coil 1 is connected to the other terminal 10B of the DC power supply 10 via a switch 11.

Next, the operation will be described. When an abnormal rise in current due to an accident such as a surge is detected by known detection means (not shown), the switch 11 is closed. When the switch 11 is closed, the voltage of the DC power supply 10 is applied to the trip coil 1 and the coil 15 connected in series, and the current increases according to the time constant of the series connection of the coils 1 and 15. FIG. 4 shows actual measured values of the temporal change of the current. In FIG. 4, the horizontal axis represents time, the vertical axis represents current value, and current value K represents a current flowing from DC power supply 10 to a series connection of trip coil 1 and coil 15 in a steady state. The operating current value K1 is a current that generates a magnetic force that causes the trip coil 1 to move the movable iron core 2 in the direction of arrow B1 against the urging force of the pulling spring 4D. Note that the current value is 0.632
K is a current value defining a time constant. A curve 25 shows a change in current when the coil 15 is not connected in series and the terminal 1C of the trip coil 1 is directly connected to the terminal 10A of the DC power supply (corresponding to a conventional configuration). In this case, the time constant is t
1 and reaches the operating current K1 after the time T1.
On the other hand, a curve 26 indicates a change in current when the coil 15 is connected to the trip coil 1 in series as shown in FIG. In this case, the time constant is t2, and reaches the operating current K1 after the time T2. That is, the operation of the movable iron core 2 is delayed by the difference between the times T2 and T1 (T2-T1). The opening time is the sum of the time T1 or T2 and the delay time of the operation due to the play of the mechanism from the connecting rod 3 to the movable contact 8. According to the first embodiment, the opening time can be extended by connecting the coil 15 to the trip coil 1 in series.

Embodiment 2 FIG. 2 shows a configuration of a second embodiment of the present invention. In the second embodiment, the iron core 16 is inserted into the hollow portion 15A of the coil 15 in order to further extend the opening time. Other configurations are the same as those of the first embodiment shown in FIG. By inserting the iron core 16, the inductance of the coil 15 increases and the time constant also increases. The change of the current in this case is shown by a curve 27 in FIG. The time required to reach the operating current K1 is T3, which is further extended from the case shown by the curve 26 in the first embodiment.

FIG. 3 shows an iron core 16 having a larger volume.
7 is shown. In this case, the inductance of the coil 15 is further increased as compared with the case where the iron core 16 is inserted (FIG. 2), and the time constant is also increased. The change in current in this case is shown by curve 28 in FIG. The time to reach the operating current K1 is T4, which is further extended from the case of the second embodiment shown by the curve 27. According to the second embodiment, the coil 15
The opening time can be easily and promptly changed by replacing the iron core 16 or 17 to be inserted into the hole. For example, the iron core 16 is used for a three-cycle circuit breaker, and the iron core 17 is
By setting for the cycle breaker, the opening time of the same breaker can be changed only by replacing the iron core 16 or 17.

[Embodiment 3] FIG. 5 shows the configuration of a third embodiment of the present invention. In the figure, a bracket 1 is attached to a coil 15.
9 is provided, and a screw 21 is inserted into a female screw 20 of the bracket 19. The core 18 is connected to the end of the male screw 21, and the core 18 can be moved to an arbitrary position in the hollow portion 15 </ b> A of the coil 15 by turning the male screw 21. Due to the movement of the iron core 18, the inductance of the coil 15 changes continuously, and its time constant also changes continuously. As a result, the opening time can be changed continuously, and the same circuit breaker can be applied to a wide range of applications.

[0011]

According to the present invention, the time constant of the trip coil can be increased by connecting the coil in series with the trip coil of the circuit breaker, and the contact opening time can be extended. Further, by inserting a predetermined iron core into the coil and changing its position, the opening time can be extended to an arbitrary value.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a first example of a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a second example of the second embodiment of the present invention.

FIG. 4 is a graph showing a temporal change of a current in the operation of each embodiment of the present invention.

FIG. 5 is a configuration diagram of a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Trip coil 2 Movable core 8 Movable contact 9 Fixed contact 15 Coil 15A Hollow part 16 Iron core 19 Bracket 20 Female screw 21 Male screw

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-55-142872 (JP, U) JP-B 6-3079 (JP, B2) JP-B 35-12635 (JP, Y1) Patent 94618 (JP, U1) C2) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01H 73/36 H01H 71/28 H01H 71/74

Claims (3)

(57) [Claims] A movable core connected to the movable contact of a circuit breaker having a fixed contact and a movable contact; a trip coil for disengaging the movable contact from the fixed contact to the movable core; and circuit breaker comprising connected in series with the trip coil, a co <br/> yl for delaying dissociation. Wherein said coil has a hollow portion, by providing a core in the hollow portion, the length of time for delaying the dissociation
Breaker comb was claim 1. 3. The coil has a hollow portion, an iron core is provided in the hollow portion, and a moving means for moving the iron core to an arbitrary position in the hollow portion is provided, whereby dissociation is delayed.
2. The circuit breaker according to claim 1, wherein the extension time can be arbitrarily changed .