JP2006134633A - Instant-type overcurrent tripping device of circuit breaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an improved instant-type overcurrent tripping device of a circuit breaker which can respond to different tripping specification requirements by using common components. <P>SOLUTION: The tripping device has: a current coil 7 which is wound around a periphery of a non-magnetic bobbin 6 being combined with a magnetic yoke 8, and is connected to a main circuit; and a plunger (a movable iron core) 9 linked to a tripping mechanism of the circuit breaker, and a restoring spring 10 which are installed inside the bobbin. When the current through the main circuit becomes a predetermined operation current or more, the tripping device trips the circuit breaker by attracting the movable iron core toward the inside of the bobbin from its standby position by magnetic force of the current coil. The current coil 7 is composed of a close coiling part 7A and a rough coiling part 7B being divided lengthwise. The coiling parts 7A and 7B are mounted on the bobbin by selecting a direction of the coiling parts 7A and 7B corresponding to a tripping specification requirement (standard specification, high instant specification), and lead terminals 7a and 7b drawn out from both winding ends of the coil are connected to the main circuit. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an instantaneous overcurrent tripping device for a circuit breaker for an automatic breaker that is applied to an electric circuit with a large inrush current, such as a primary side of a transformer or an electric motor, and performs overcurrent protection.

As the overcurrent tripping device for the circuit breaker mentioned above, a tripping unit that includes a thermal overload tripping device and an electromagnetic instantaneous overcurrent tripping device is mounted on the circuit breaker body. Further, it is known that the operation end of each tripping device is connected to a tripping mechanism of a circuit breaker to perform overcurrent protection (see, for example, Patent Document 1), and its assembly structure is shown in FIG. .
In FIG. 3, 1 is an assembly base (insulator) of a unit, 2 is a main circuit terminal fitting on the load side, 3 is a thermal overload tripping device in which a heater 3b is added to a bimetal 3a, and 4 is an electromagnetic instantaneous The overcurrent tripping device 5 is a fixed contact of the main circuit assembled on the lower surface side of the assembly base 1.
Here, the instantaneous overcurrent tripping device 4 includes a non-magnetic material (resin) cylindrical bobbin 6, a current coil (trip coil) 7 wound around the outer periphery of the bobbin 6, and a magnetic combined with the bobbin 6. It comprises an assembly of a yoke 8, a plunger (movable iron core) 9 having a trip lever (operating end) 9a at the top and fitted into the bobbin 6, and a return spring 10 for pushing the plunger 9 to the standby position. Lead terminals 7a and 7b drawn from both ends of winding start and end of coil 7 are joined to terminal plate 11 of main circuit and terminal plate 12 leading to bimetallic heater 3b, and between terminal fitting 2 and fixed contact 5 The bimetal 3 with a heater and the current coil 7 are connected in series so that the main circuit current flows. Although not shown, the bimetal 3a of the thermal overload tripping device 3 and the tripping lever 9a of the plunger 9 provided in the instantaneous overcurrent tripping device 4 include a tripping mechanism (latch of the circuit breaker). ).

With the above configuration, when an overcurrent such as a short circuit current flows in the main circuit circuit and the current value exceeds the operating current defined in the specification, the plunger 9 of the instantaneous overcurrent trip device 4 causes the magnetic action of the current coil 7 to In response to the magnetic attraction force, the bobbin 6 is pulled in from the standby position shown in the figure, the tripping mechanism responds to this movement, and the circuit breaker trips.
JP 2002-170474 A

Regarding the above-described instantaneous overcurrent tripping device, the operating current has different specifications depending on the load to be protected. That is, in a circuit breaker using a motor with a large starting current as a load, it is necessary to avoid the circuit breaker from tripping due to an inrush current when the motor is started.
In this regard, in the conventional instantaneous overcurrent tripping device, as means for changing the specifications of the operating characteristics, the number of turns of the current coil 7 in FIG. 3 is changed, the spring force of the return spring 10 and the length of the plunger 9 are changed. The current situation is to deal with this by changing the dimensions.
However, in the above-mentioned method, there are many types of dedicated parts with different specifications, which results in high part costs and complicated parts management. In addition, there is a risk of mistaken combinations of parts for the required specifications in the manufacturing process. Improvement measures are desired.
The present invention has been made in view of the above points, and its purpose is to be able to cope with required specifications having different tripping characteristics by sharing component parts with the aim of simplifying part management and reducing part cost. It is another object of the present invention to provide an instantaneous overcurrent tripping device for a circuit breaker improved.

In order to achieve the above object, according to the present invention, an instantaneous overcurrent of a circuit breaker that is mounted on a breaker body and operates when an overcurrent flows in a main circuit to instantaneously trip a breaker. A tripping device comprising a non-magnetic bobbin combined with a magnetic yoke and connected to a main circuit by winding a current coil around the outer periphery of the non-magnetic bobbin, and the bobbin is connected to a tripping mechanism of a circuit breaker. Built-in core and return spring. When the main circuit current exceeds the specified operating current, the breaker trips by attracting the movable iron core from the standby position to the inside of the bobbin by the magnetic force of the current coil. In what was made to
The current coil is divided into two sections along its longitudinal direction to form a densely wound portion and a coarsely wound portion, and the direction of the coil is tripped and selected according to the required specifications of the characteristics and attached to the bobbin. Lead terminals drawn from both ends of winding start and winding end are connected to the main circuit.

  For the required specifications with high operating current, in addition to selecting the direction of the current coil, reverse attraction is one in which one end is connected to the magnetic yoke and the movable iron core is attracted in the direction opposite to the magnetic attraction force of the current coil. An armature is provided (claim 2).

The above configuration produces the following effects. That is, with the current coil having a densely wound portion and a coarsely wound portion formed on the coil as a common part, in the standard specification tripping device, the densely wound portion of the current coil is positioned relatively to the stroke end side with respect to the movable iron core. For a tripping device with a required specification (high instant) that is mounted on the bobbin and whose operating current is higher than the standard specification, reverse the direction of the current coil so that the coarse winding is on the stroke end side of the movable iron core. Mount on the bobbin so that they are positioned relative to each other.
When an exciting current is passed through the current coil in this assembled state, the magnetic field strength of the magnetic path along the longitudinal direction of the bobbin becomes larger in the densely wound area than in the coarsely wound area. This makes it possible to effectively move the movable iron core from the standby position to the operating position based on the relative positional relationship between the densely wound portion and the coarsely wound portion corresponding to the direction of the current coil mounted on the bobbin and the movable iron core. There is a difference in force, and the magnetic attraction force acting on the movable iron core is relatively weaker in the high instant specification coil arrangement than in the standard specification coil arrangement described above under the same current. Therefore, in the high instant specification, the coil current required for stroke operation of the movable iron core is larger than that in the standard specification, and in the high instant specification, the operation current of the circuit breaker is increased.

In other words, by using the same current coil as a common part and selecting the direction of the coil to be mounted on the bobbin, it is possible to assemble an instantaneous overcurrent trip device that supports standard specifications and high instant specifications, reducing costs, and parts. Management can be simplified.
In addition to the above configuration, the tripping operation current can be set higher by providing a reverse attracting armature that connects one end to the magnetic yoke and attracts the movable iron core in the direction opposite to the magnetic attraction force of the current coil. can do.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on the examples shown in FIGS. In the drawings of the respective embodiments, members corresponding to those in FIG.

FIGS. 1A to 1C show an embodiment according to claim 1 of the present invention, and FIGS. 1A and 1B show assembly structures corresponding to standard specifications and high instant specifications, respectively. Yes.
That is, the overall structure of the overcurrent tripping device is basically the same as that of FIG. 3, but the current coil 7 mounted on the outer periphery of the bobbin 6 is two along the longitudinal direction of the bobbin with respect to the instantaneous overcurrent tripping device 4. A densely wound portion 7A in which the coil strands are overlapped and divided into two sections and a coarsely wound portion 7B having a coarse coil pitch are formed, and the lead is pulled out to the side with the directions aligned from both ends of winding. Terminals 7a and 7b are connected to the main circuit as in FIG.
Here, with the current coil 7 as a common part, in the standard specification shown in FIG. 1A, the current coil 7 is inserted into the bobbin 6 with the tightly wound portion 7A facing down and the coarsely wound portion 7B facing up. 1B, in the high instant specification shown in FIG. 1B, the current coil 7 is mounted on the bobbin 6 with the coarse winding portion 7B facing down and the dense winding portion 7A facing up, Lead terminals 7a and 7b pulled out from both ends of the coil at the assembly position are connected to the main circuit.

On the other hand, the cylindrical bobbin 6 to be a resin molded product has a flange portion 6a at the top and a rectangular stopper piece 6b for holding the plunger 9 in the standby position, and the flange portion 6a has an upper end side of the magnetic yoke 8. The lower end of the bobbin 6 is placed on the arm portion 8b branched from the lower portion of the magnetic yoke 8 to stand upright on the assembly base 1. It is supported. The plunger (movable iron core) 9 is fitted into the bobbin 6 from above together with the return spring 10, and the tripping lever 9a of the plunger 9 pushed upward by the return spring 10 is applied to the stopper 6b and held at the standby position. In this standby position, the tip of the plunger 9 fitted into the bobbin 6 is located slightly above the tightly wound portion 7A of the current coil 7.
In the above assembly structure, in the standard specification shown in FIG. 1A, the tightly wound portion 7A of the current coil 7 is positioned relative to the plunger 9 on the stroke end side, and in the high instant specification shown in FIG. The coarse winding portion 7B of the coil 7 is positioned relative to the stroke end side, and the operating current that causes the circuit breaker to trip when an overcurrent flows in the main circuit is compared with FIG. The assembly state of b) becomes higher.

  Therefore, by using the current coil 7 as a common part, the direction of the coil wound around the bobbin 6 is selected to the state shown in FIGS. 1A and 1B in accordance with the required specifications of the circuit breaker. In this way, it is possible to assemble an instantaneous overcurrent trip device that supports standard specifications and high instant specifications without using special parts.

2 (a) to 2 (d) are related to claim 2 of the present invention based on the first embodiment, wherein the setting of the tripping operation current is further enhanced to meet the requirement of high instant requirements. An example is shown.
In this embodiment, in addition to the assembly structure shown in FIG. 1B, a reverse suction armature 13 made of a magnetic material is additionally provided above the plunger 9. As shown in FIG. 2 (c), the reverse attracting armature 13 has a structure in which a forked leg piece 13 b is drawn downward from a flat armature board 13 a, and the tip of the leg piece 13 is connected to the upper surface of the magnetic yoke 8. The magnetic yoke 8 is magnetically coupled by fitting into the concave portions 8a-1 formed on both sides, and the armature plate 13 is opposed to the upper surface of the tripping lever 9a of the plunger 9 at this assembly position.
In the above configuration, the reverse attracting armature 13 connected to the magnetic yoke 8 is energized by energization excitation of the current coil 7, and the magnetic attracting force upward from the reverse direction to the downward magnetic attracting force by the current coil 7 with respect to the plunger 9. Act. Thereby, the operating current setting of the current coil 7 required for moving the plunger 9 from the standby position to the operating position can be further increased than in FIG.

BRIEF DESCRIPTION OF THE DRAWINGS It is an assembly block diagram of the overcurrent trip apparatus concerning Example 1 of this invention, (a), (b) is a side view of the assembly state corresponding to a standard specification and a high instant specification, respectively, (c) is (a). Top view of FIG. 4 is an assembly structure diagram of an overcurrent tripping device according to Embodiment 2 of the present invention, where (a) is a side view, (b) is a plan view, and (c) is an external perspective view of a reverse suction armature in (a). (D) is a sectional view taken along line XX in (a). Side view showing the assembly structure of a conventional overcurrent trip device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Assembly base 3 Thermal overload trip device 4 Instantaneous overcurrent trip device 6 Bobbin 7 Current coil 7A Close winding part 7B Coarse winding part 7a, 7b Lead terminal 8 Magnetic yoke 9 Plunger (movable iron core)
10 Return spring 13 Reverse suction armature

Claims (2)

This is an instantaneous overcurrent tripping device for a circuit breaker that is mounted on the circuit breaker body and operates when the overcurrent flows through the main circuit to instantaneously trip the circuit breaker. A current coil is wound around the outer periphery of the bobbin and connected to the main circuit, and the bobbin has a plunger-type movable iron core and a return spring linked to the tripping mechanism of the circuit breaker. In the case where the breaker is tripped by attracting the movable iron core from the standby position to the inside of the bobbin by the magnetic force action of the current coil when the predetermined operating current is exceeded,
The current coil is divided into two sections along its longitudinal direction to form a densely wound portion and a coarsely wound portion, and the direction of the coil is tripped and selected according to the required specifications of the characteristics and attached to the bobbin. Instantaneous overcurrent tripping device for circuit breaker, characterized in that the lead drawn from both ends of winding is connected to the main circuit. 2. The instantaneous overcurrent tripping device according to claim 1, wherein for a required specification having a high tripping operation current, one end is connected to a magnetic yoke and the movable iron core is attracted to a standby position from a direction opposite to the current coil. An instantaneous overcurrent tripping device for a circuit breaker comprising a suction armature.

Images