JPS628422A - Circuit breaker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention provides short-time protection according to the magnitude of overcurrent in order to facilitate protection coordination with other devices and coordination with own overcurrent tolerance. Disconnection and instantaneous use relate to circuit breakers that have the function of performing sushi.

[Background of the Invention] Conventionally, general-purpose circuit breakers used to protect general loads such as electric motors use a thermal element to perform long-time disconnection in response to overcurrents up to several times the rated current. For large currents such as short-circuit currents that exceed the long-time operation range, most devices used an electromagnet to perform instantaneous disconnection.

As a short-time tripping device that operates in a current range intermediate between the long-time operating range and the instantaneous operating range, an escapement that provides resistance by an ankle and an ankle gear is connected to the movable core of the electromagnet to perform a predetermined time-delaying operation. There are devices designed to do this, but they are expensive because the escapement itself is a complicated mechanism using precision parts, and they are designed specifically for short-term tripping, separate from the instantaneous disconnection electromagnet. Since it requires an electromagnet and a connection mechanism between the electromagnet and the escapement, if the three elements of long time, short time, and instantaneous are used together, the entire tripping mechanism becomes very large and expensive, and it is difficult to actually use it. is a large-capacity model (200OA frame, etc.) for the # line, and was only used for specific purposes such as selectively disconnecting between lower-order protectors.

By the way, in many motor loads, which are the most common equipment to be protected, the inrush current at the time of starting reaches more than 10 times the steady load current. In order to avoid malfunction of the disconnection device, it is necessary to select a circuit breaker with a rated current value of at least 1.5 times the steady load current, which is not only uneconomical but also increases the minimum current value for instantaneous use. This made it difficult to properly protect motors, wires, etc. from overcurrent. in this case,
If the current range is slightly lower than the lower limit current value for instantaneous use,
If it is possible to perform a short-time trip operation of a cycle or several cycles, it is possible to properly protect motors, electric wires, etc. using a circuit breaker with a lower rated current value while avoiding malfunctions caused by the above-mentioned inrush current. Become so.

In addition, lower protectors (thermal relays, etc.) and upper protectors (overcurrent relays, high voltage fuses, etc.) will be described later.
There are many benefits to adding a short-time trip function to a general-purpose circuit breaker for general loads in other aspects, such as coordination with the circuit breaker itself and coordination with the overcurrent capacity of the circuit breaker itself.

[Object of the Invention] The object of the present invention is to provide a general-purpose model for general loads with both short-time pull-out and instant-time draw functions with a small, simple, and inexpensive configuration.

The object of the present invention is to provide a circuit breaker equipped with a new tripping mechanism that can achieve both economic efficiency and protection coordination.

[Summary of the Invention] The present invention provides a circuit breaker equipped with an electromagnet consisting of a fixed core and a movable core as a tripping element that responds to an overcurrent, in which the movable core is used for comparison of inertia force with a relatively low operating current value. It is divided into a first movable core part with a large target and a second movable core part with a relatively high operating current value and a relatively small inertia force, and the first and second movable core parts are subject to mutual interference. The device is characterized in that the opening/closing mechanism is combined so that the opening/closing mechanism is tripped via the tripping shaft even if either of them is activated.

[Embodiments of the Invention] Examples of the present invention will be described below with reference to the drawings.

1 to 4 are diagrams showing one embodiment of the present invention, with FIG. 1 showing a cross section of the tripping mechanism, and FIG. 2 showing an exploded view of the electromagnet portion. FIGS. 3 and 4 are state diagrams of short-time operation and instantaneous operation, respectively.

This embodiment is configured as follows.

■ is a molded case that houses the mechanical part of the circuit breaker, 2 is a bimetal which is a thermal element for disconnection during long operation, 3 is a heater through which the load current flows, 4 is a fixed core, and the magnetic plate is bent into a U shape. It is fixed on the base of the molded case 1 so as to surround the bimetal 2 and the rising portion of the heater 3 along the bimetal 2 from three sides.

The movable core, which together with the fixed core 4 constitutes an electromagnet, is divided into a first movable core section 5 and a second movable core section 6.

Each movable core part 5, 6 consists of a flat magnetic body 7,8 forming a magnetic path and support plates 9,10 joined to each magnetic body.In this example, the plate thickness of the magnetic bodies 7,8 is By changing the weight, the weight of the first movable core section 5 can be made larger than the weight of the second movable core section 6. The shaft portion 9a of the support plate 9 is connected to the bearing hole 11a of the fixed support portion 11 fixed on the mold case 1.
The first movable core part 5 and the second movable core part 6 engage with each other to form a rotation fulcrum for the fixed core 4 of the first movable core part 5, and the first movable core part 5 and the second movable core part 6 are engaged with the bearing hole 9b of the support plate 9 and the support plate 9. They are connected via a shaft 12 passed through the bearing hole 10a of the plate 10, and the shaft 12 is
This serves as a pivot point for the movable core portion 6 relative to the fixed core 4.

13 is a return spring that separates the first movable core portion 5 from the fixed core 4; 14 is a return spring that separates the second movable core portion 6 from the fixed core 4; 9c and the spring catch of the fixed support part 11 are suspended between the part 11b, and the return spring 14 is suspended between the spring catch of the support plate 9 and the part 9d.
The spring hook of the support plate lO is suspended between the part tob and the support plate lO. Due to the force of these return springs 13 and 14, the movable core portion 5 of the cylinder 1 is always stopped at the position where its support plate 9 hits the stopper llc of the fixed support portion 11, and the second movable core portion 6 is The plate 10 stops at the position where it hits the support plate 9 of the first movable core part 5.

Here, the value of the load current when the first and second movable core parts 5.6 are attracted to the fixed core 4 and start operating is defined as the "operating current value". This operating current value is determined by the attraction distance (air gap length) of each movable core portion 5.6 with respect to the fixed core 4 and the return spring 13 that each movable core portion 5.6 receives.
．． Here, the attraction distance to the first movable core portion 5 is set relatively short, and the force of the return spring 13 is relatively weak, so that the movable core portion 5 receives a relatively low current. The movable core section 6 is set to start operating at a relatively high current by setting a relatively long suction distance to the second movable core section 6 and making the force of the return spring 14 relatively strong. Set it so that it starts operating at the value.

Next, the operation will be explained.

When the load current increases and becomes an overcurrent of several to ten times the rated current, the bimetal 2 bends counterclockwise due to the heat generated by the heater 3. As a result, the trip shaft 16 common to each pole is pushed through the adjustment screw 15 and rotated in the same direction, and the latch 17 is released after a delay time according to the current value.
The hook 18 of the opening/closing mechanism, which had been locked, is released and the opening/closing mechanism is tripped and operated.

When the overcurrent becomes 10 to 10 times larger than the rated current, the operating current value is set to be relatively low.The first movable core portion 5 is formed by the fixed core 4 and the magnetic material 7. The attractive force generated in the magnetic circuit overcomes the return spring I3 and attempts to start rotating toward the fixed core 4 side. However, the first
Since the movable core portion 5 has a large weight and therefore a large inertia force, there is a delay in the suction operation toward the fixed core 4 side due to the inertia force, resulting in a short time delay of about 1 cycle (20 ms). . At this time, the second movable core section 6 having a rotational fulcrum above the first movable core section 5 is also connected to the first movable core section 5.
At the same time, it moves to the fixed core 4 side. and.

The second movable core section 6 pushes the tripping shaft 16 located on its movement path and rotates it counterclockwise, thereby bringing the opening/closing mechanism into a tripping operation (FIG. 3).

If the overcurrent becomes a large value exceeding ten times the rated current, the second movable core portion 6 with a relatively high operating current value will generate an overcurrent in the magnetic circuit formed by the fixed core 4 and the magnetic material 8. The suction force overcomes the return spring 14 and rotates toward the fixed core 4 side. The second movable core portion 6 has a small weight;
Therefore, since the inertial force is small, it operates instantaneously without waiting for the first movable core portion 5 to operate, and rotates the tripping shaft 16 counterclockwise to cause the opening/closing mechanism to trip.
Figure 4).

This example is applied to a general-purpose circuit breaker for general loads, and without using the complex, expensive, and space-consuming escapement described above, it can be used in short-time and short-time operations in addition to normal long-time operation and instantaneous operation. Operation functions can be added. In particular, in this embodiment, the return spring 14 that separates the second movable core part 6 from the fixed core 4 is suspended between the first movable core part 5 and the second movable core part 6, so that it is possible to perform short-time operation. , the first movable core section 5 can be sucked together with the second movable core section 6 without being constrained by the return spring 14 at all, and the inertial mass of the second movable core section 6 can be transferred to the first movable core section 6. Since it can be used in addition to the inherent inertial mass of the movable core section 5, the entire movable core can be made smaller, and the movement of the first movable core section 5 can be transferred via the second movable core section 6 to the trip axis. 16
Since the motion can be transmitted to the trip shaft 16, the mechanism for transmitting the motion to the trip shaft 16 is also simplified. In addition, by providing the rotation fulcrum of the second movable core portion 6 on the first movable core portion 5, the first movable core portion 6
The support mechanism for the second movable core portion 5.6 can be simplified and downsized easily. As a result of the above, according to this example,
A trip mechanism that combines three elements (long time, short time, and instantaneous) can be constructed compactly, easily, and inexpensively, and can be used as a general-purpose circuit instead of the conventional trip mechanism that has two elements (long time and instantaneous). It can also be easily applied to circuit breakers.

Next, the cooperativeness of the circuit breaker according to the present invention will be explained in comparison with a general hardwired circuit breaker.

FIG. 5 is an explanatory diagram of cooperation with load equipment.

A is the starting characteristic of the load equipment (electric motor, etc.), B is the long-time operation characteristic of the circuit breaker, C is the total breaking time of the instantaneous disconnection of the general circuit breaker, D is the unlatching time as above, and E is the embodiment of the present invention. The short-time version is the total cut-off time of the sushi, F is the unlatching time as above, G is the total cut-off time of the sushi for the instantaneous version of the embodiment of the present invention, H is the unlatching time of the same as above, I is the overcurrent withstand capacity of the electric wire According to the embodiment of the present invention, even if the inrush current Is at the time of starting the load equipment flows for a period longer than the instantaneous unlatching time in a general circuit breaker and the circuit breaker malfunctions, according to the embodiment of the present invention, - Obtain the operating characteristics shown by E-G, and have an unlatching time F of about one cycle that does not cause the opening/closing mechanism to trip in a current range intermediate between the long-time operating range and the instantaneous operating range. Therefore, malfunctions due to inrush current Is at startup can be prevented. Therefore, it is not necessary to use a circuit breaker with a large rated current to avoid malfunctions as in the past, and it is economical. Also, by combining the short-time disconnection characteristics and instantaneous disconnection characteristics, overcurrent of load equipment and wires is reduced. Protection can be provided with sufficient margin.

Figure 6 is an explanatory diagram of cooperation with a thermal relay used as an overload protector for a motor, and Figure 7 is an illustration of the high voltage side protector (
An explanatory diagram of coordination with overcurrent relays, high voltage fuses, etc.),
Figure 8 is an explanatory diagram of the coordination with the overcurrent withstand capacity of the circuit breaker itself.As shown in these figures, according to the embodiment of the present invention described above, the minimum operating current value for short-term operation is generally Since the current can be set lower than the instantaneous operating current value of the circuit breaker, it is easy to coordinate with upper and lower protectors, such as preventing melting of the thermal relay heater and selectively disconnecting the high-voltage side protector. In particular, there is a margin in the design for the overcurrent withstand capacity of the heater (heater), and a more economical design can be achieved.

9 to 12 show other embodiments of the present invention.

In the embodiment shown in FIG. 9, a disc-shaped weight 19 as an inertial mass body is attached near the pivot point of the first movable core part 5. It is possible to provide the inertia force necessary for the time-delaying operation without making the plate thickness of the magnetic body 7 particularly thick, and the inertia force can be adjusted by changing the weight of the weight 19 as necessary. .

In the embodiment of FIG. 10, the suspension mode of the return springs 13, 14 is changed, and the return spring 13 is placed between the spring hook part 9C of the first movable core part 5 and the spring catch part 11b of the fixed support part 11. The spring hook of the second movable core portion 6 is the same as that of the portion 10b, and the spring hook of the fixed support portion 11 is the same as that of the portion 11b, so that the return spring 14 is suspended independently.

FIG. 11 is a diagram of its operation state, in which (a) shows the short-time operation state and (b) shows the instantaneous operation state. In this embodiment, the first movable core part 5, which has a relatively low operating current value and a relatively large inertia force, uses the shaft part 9a of the support plate 9 that engages with the bearing hole 11a of the fixed support part 11 as a pivot point. In addition, the second movable core part 6, which has a relatively high operating current value and a relatively small inertial force, rotates around the shaft 12 that connects the support plate 9 and 1O, and independently operates without interference from each other. works, 1st
The movable core part 5 overcomes the return spring 13 and moves the fixed core 4
When performing a suction operation to the side, the first movable core portion 5 is not constrained by the other return springs 14, and the movement of the first movable core portion 5 is suppressed by the support plate 9 without going through the second movable core portion 6. Part 9e
is transmitted to the trip shaft 16.

The embodiment shown in FIG. 12 is an example in which a laminated core is used for the electromagnet, and is applied to a relatively large-capacity model in which core loss is a problem.

Parts corresponding to those in the previous embodiment are denoted by the same reference numerals.
A first movable core portion 5 having a relatively large inertial force and a second movable core portion 6 having a relatively small inertial force are arranged one above the other so as to be slidable in the vertical direction along a guide (not shown). Each of them faces the fixed core 4. The return spring 13 is suspended between the first movable core part 5 and a fixed support part (not shown), and the return spring 14 is suspended between the rod 20 attached to the first movable core part 5 and the second movable core part 6. As in the previous embodiment, the first movable core section 5 starts operating at a relatively low current value, and the second movable core section 6 starts operating at a relatively high current value. The respective suction distances and strengths of the return springs 13 and 14 are determined. therefore,
When the load current flowing through the conductor 21 reaches the operating current value of the first movable core portion 5, the first movable core portion 5 releases the return spring 13.
is attracted by the fixed core 4 and the second movable core part 6
The suction operation is delayed for a short time due to inertia, and the tripping shaft 16 is pulled out via the rod 22.
, and trip the opening/closing mechanism. Further, when the load current becomes a large value exceeding the operating current value of the second movable core section 6, the second movable core section 6 returns the spring 14 without waiting for the operation of the first movable core section 5. It overcomes this and is attracted to the fixed core 4, and the suction action becomes an instantaneous action and similarly rotates the trip shaft 16 via the rod 22.
The opening/closing mechanism is tripped and operated.

This embodiment also provides both the functions of short-time pulling sushi and instant pulling sushi with a smaller and simpler configuration than those using a conventional escapement. Although not shown in the drawings, it goes without saying that a long time release function using a thermal element can also be used.

[Effects of the Invention] According to the present invention, the movable core of the trip magnet is divided into two parts, and the first movable core portion, which has a relatively low operating current value and a relatively large inertia force, performs a short-time trip. Since the second movable core part, which has a relatively high operating current value and a relatively small inertia force, is configured to perform instantaneous tripping, an escapement is used as a time delay element, and in combination with a dedicated electromagnet, a short time trip can be achieved. Compared to the conventional method that provides a tripping function, the entire tripping mechanism can be significantly smaller, and the structure is simple and low cost. Also, since it does not use a precision mechanism such as an escapement, it reduces vibration and heat.

Stable and highly reliable against environmental conditions such as dust.

In addition to the conventional long-time and instantaneous trip functions, it is easy to add a short-time trip function to small- to medium-sized general-purpose circuit breakers, and as a result, the load can be increased without increasing the rated current. It prevents malfunctions due to starting current, facilitates coordination with other protectors installed in one circuit, and provides a margin for the overcurrent withstand capacity of the circuit breaker itself, allowing for economical design. .

[Brief explanation of drawings]

FIG. 1 is a side sectional view of a tripping mechanism section showing an embodiment of the present invention, and FIG. 2 is an exploded perspective view of the electromagnet section.
Figures 3 and 4 are operating state diagrams similar to the above, Figures 5 to 8 are explanatory diagrams of operating characteristics, and Figure 9 is a side sectional view of another embodiment of the present invention in which a weight is added as an inertial mass. , Figure 10(a)
, (b) is a side sectional view and a front view of the movable core portion of another embodiment of the present invention in which the suspension style of the return spring is different, and FIG. 11 (
a) and (b) are the same operating state diagrams as above, and Fig. 12 (a) and (
b) is a side sectional view and a front view of another embodiment of the present invention using a laminated core for the electromagnet. 4... Fixed core 5... First movable core part 6... Second movable core part 11... Fixed support parts 9a, lla... Rotation fulcrum 9b of the first movable core part ,
10a, 12... Rotation fulcrum 13 of the second movable core portion.
14... Return Spring Agent Patent Attorney Junnosuke Nakamura 1-1 Figure 5 IF 5 Figure 6 Off Figure 1

Claims (4)

[Claims] (1) In a circuit breaker equipped with an electromagnet consisting of a fixed core and a movable core as a trip element that responds to overcurrent,
The movable core is divided into a first movable core portion having a relatively low operating current value and a relatively large inertial force, and a second movable core portion having a relatively high operating current value and a relatively small inertial force, A circuit breaker characterized in that the first and second movable core parts operate without interference from each other and are combined so that the opening/closing mechanism and tripping operation are performed even if either of them operates. (2) a return spring that separates the first movable core from the fixed core is suspended between the first movable core and the fixed support;
Claim (1) characterized in that a return spring for separating the second movable core part from the fixed core is suspended between the first movable core part and the second movable core part. circuit breaker. (3) A claim characterized in that a return spring that separates the first and second movable core parts from the fixed core is independently suspended between each movable core part and the fixed support part ( The circuit breaker described in item 1). (4) The first movable core part has a pivot point relative to the fixed core on the fixed support part, and the second movable core part has a pivot point relative to the fixed core above the first movable core part. A circuit breaker according to any one of claims (1) to (3).