JPS62126511A - Contactor device - 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 Industrial Application] The present invention relates to a contact device for a switch or a circuit breaker, and more particularly to a contact device provided with a main contact and a contact not equal to the main contact.

[Conventional technology]

In a switchgear with a large current carrying capacity, the contactor is divided into a main contactor and an arc contactor, and in the closed state, the circuit current is passed through the main contactor, and when the circuit is opened, the main contactor opens first, causing a slight arcing contact. Delayed opening of the arc contact is conventional practice. For example, FIG. 11 shows a conventional device.

As shown in FIG. 12 in a plan view and a side sectional view showing a closed circuit state, a first fixed terminal conductor 1 and a second fixed terminal conductor 2 are provided at a distance from each other.

A fixed main contact 3 and a fixed arc contact 4 are attached to the first fixed terminal conductor 1 to form a fixed contact device.

The movable contact device 5 has a movable main contact 7 having a movable main contact 6 so as to come into contact with and separate from the fixed main contact 3, and a movable arc contact 8 mounted so as to come into contact with and separate from the fixed arc contact 4. The movable arc contacts 9 are arranged in parallel with each other, and the movable arc contacts 9 are arranged so as to protrude more forward than the movable main contacts 7 provided on both sides. It is attached integrally to the.

The tail ends of the movable main contact 7 and the movable arc contact 9 are connected to the second fixed terminal conductor 2 via flexible conductors 12 and 13, respectively, and each of the movable contacts 7 and 9 and a contact support device Springs 14 and 15 are installed between the main contacts 3 and 6 and the arc contacts 4 and 8 to apply contact pressure to the main contacts 3 and 6 and the arc contacts 4 and 8, respectively. The contact support device 11 has a rotating shaft 1 supported by a fixed frame (not shown).
6 and connected to the contact support device 11 by a pin 17, the opening/closing operation mechanism member 18 is rotated to the opening/closing position about the rotation shaft 16 as a fulcrum. An insulating crossbar 1 attached to the upper part of the contact support device 11
Reference numeral 9 is connected to a contact supporting device 11 of the other pole so that various types of circuit breakers operate together.

When the movable contact device 5 is rotated to open the circuit, the movable main contact 6 separates from the fixed main contact 3, and a little later, the movable arc contact 8 separates from the fixed arc contact 4. When closing, the movable arc contact 8 first comes into contact with the fixed arc contact 4, and a little later, the movable main contact 6 comes into contact with the fixed main contact 3.

Further, the arc extinguishing device 20 has a V-shaped notch 2ja on one side.
A plurality of rectangular arc-extinguishing plates 21 made of a magnetic material are arranged so as to be stacked at intervals and held on a support plate 22 in an insulated state. The movable arc contact 8 is inserted into the arc extinguishing device 20 so that it can open and close within the notch space formed by the main contacts 3 and 6 of the plurality of arc extinguishing plates.

Arc-extinguishing plate legs 211) formed on both sides of the notch 21a)
It is disposed so as to face the tip edge 21C of.

In the closed circuit state of such a contactor device, the main contacts 3,
The main contacts 3, 6 upon opening due to the current carried by 6
There is a problem in that as the breaking current increases with the occurrence of an arcing phenomenon, and as the number of openings and closings increases, the main contact 3.6 is roughened by the arc and the current carrying capacity is reduced. In particular, in a switchgear in which the movable contact device 5 opens and closes by rotating around a fixed fulcrum 16 as shown in FIGS. 9 and 10, the length of the arm of the movable main contact 7 is Because it is shorter than the arm length of the movable arc contactor 9, the breaking distance is shorter between the main contacts 3 and 6 than between the arc contacts 4 and 8.
The main contact 6.6 is shorter than the arc contact 4,
8, the arc extinguishing device 20 is placed opposite the arc extinguisher 20, so once an arc occurs between the main contacts 6 and 6, it tends not to be extinguished easily. A high-speed arc extinguishing action may not be possible in the breaking current region.

Contact devices with this type of structure include air circuit breakers and molded case circuit breakers with relatively large rated currents.

Generally used for switches etc. 1 usually each contact 7
, 9 are connected in a short-circuited manner to a common second fixed terminal conductor 2 via a flexible conductor 12.13. Each contact 7,9 is supported on a common shaft 10, with each contact 7.
9 can be rotated independently. Usually, the common shaft 10 is made of steel material with high tensile strength to prevent deformation due to electromagnetic force or mechanical force, and each contactor 7.9
Although they are electrically short-circuited by this common shaft 10, the resistance is quite high, and in fact the current is effectively exchanged between the adjacent respective contacts 7 and 9 through this common shaft 10. It cannot be done.

The electrical equivalent circuit of such a contact device is shown in FIG. In FIG.

P: Power supply side short circuit point %Q: Load side short circuit point, x-y: Common axis position of main contact and arc contact.

Ral: Internal resistance of fixed arc contact + Rac”
Resistance between the arc contacts, Ra□: Internal resistance of the movable arc contact, Ras: Internal resistance of the flexible conductor of the movable arc contact t "ac" Inductance between Y and P of the movable arc contact I, aJ : Inductance between arc contacts Y-Q, Rm, : Internal resistance of fixed main contact, RI] 1°: Resistance between main contacts.

Rrn2: Internal resistance of the movable main contact * Rms: Internal resistance of the flexible conductor of the movable main contact, L engineering. Inductance between x and p of two movable main contacts, LrnL: inductance between X and Q of movable main contacts, R8: resistance of common axis of movable main contact and movable arc contact, 1o: total current,
1a: arc contactor current, iIn: main contactor current, 1
゜: Circulating magnetic current between the main contact and the arc contact, θ: Voltage between the terminals. In this figure, the arc contact and the main contact are divided in parallel on the movable side, but are divided on the fixed side. However, the principle is the same.

[Problem that the invention seeks to solve]

In Fig. 13, if the common axis resistance R6 is very large, one circuit is essentially a parallel circuit number of the arc contactor circuit and the main contactor circuit, so in equation (1), Since the inductance of the circuit is usually smaller than the resistance, if the voltage drop due to the inductance is ignored for the commercial frequency current, the shunt ratio between the arc contact current ia and the main contact current 1m is as follows.

Generally, the number of main contacts in parallel is large depending on the rated current, so the resistance is small, and the main contact current im is the arc contact current 1
Since it is large compared to a, it is unavoidable that an arc is generated when the main contact is separated.

In the above equation (2), substantially the arc contact current ia
, it is the resistance between the arc contacts that governs the magnitude of the main contact current 1m. , the resistance Rrno between the main contacts, the internal resistance Ra51 of the flexible conductor of the arc contact, and the internal resistance Rm3 of the flexible conductor of the main contact.

When the contacts begin to separate in this condition.

First, the main contact begins to open and an arc is generated.

At the same time, an arc voltage is generated. If the arc voltage is considered to be the product of the arc resistance and the main contactor current 1 m, it may be assumed that the resistance Rmc between the main contacts increases rapidly as the main contacts are separated. A phenomenon in which the main contact current 1rn decreases and the arc contact current 1a increases due to the generation of arc voltage in the main contact.

That is, a commutation phenomenon occurs, which is thought to be caused by a circulating current of 1° flowing as shown in FIG.

In Fig. 14, em is the electromotive force of the loop circuit, but in reality, it is 0m '' (increment of RmC) '' m - (increment of RaC) Xia, which is the increment of resistance Rmo between the main contacts. is expected to be larger than the increase in resistance Rac between the arc contacts. The total resistance is Ro, and the total inductance is R. Expressed as.

Ro==R, ten Rao ten Ra2+R, S ten Rm, ten R
m2+Rm.

If LO=Lao×La,+Lm0+Lm,.

1”° ・・・・・・・・・(3) Roic is sufficient. 1 piece = e. In this case, for example, if a conventional device is equipped with 2 sets of main contacts and 1 set of arc contacts. Let's find the values of R8 and L of a 16QOA type molded circuit breaker.

was gotten. The value of Ro increases as the electrical switching increases, the contact resistance of the arc contact increases, so Ro also increases, but L
The value of o remains unchanged. Furthermore, L.

The value of % is the formula between two parallel conductors. However, a and b are the radii of each conductor, and d is the distance between the centers, and is proportional to the length of the parallel conductor part.

In the above equation (3), for simplicity, θ is the DC electromotive force E
If we consider that E:IV, when formula (3) is illustrated using the data of formula (4), it corresponds to the curve (■) in the circulating current 1°/hour characteristic diagram shown in FIG.

In FIG. 5, point A is the circuit current in, GOOA (ac
, r, m, s), the maximum current flowing in the two circuits of the main contactor is 10,0OOXT×TA=920OA and (3
), and if E:IV, it means that the main contact current - disappears after 382μ, θθC.

As the resistance Rao between the arc contacts increases due to repeated current switching, the time constant and current rush rate do not decrease, but the maximum current value decreases, and in E:IV, 1° of circulating current becomes 920OA. , the main contact current box will not reach zero unless you wait until the higher main contact arc voltage E grows, and therefore the arc power burden on the main contact increases and wear on the main contact increases. I'll come. Circulating current i. If Rao does not increase rapidly, the metal vapor ion concentration between the main contacts will increase and the resistance Rao between the arc contacts will increase.
> If the resistance Rmo between the main contacts is reached, the circulating current of 1° flows in the direction opposite to the arrow in FIG. 14, and the current in the main contacts increases, making it difficult or impossible to break.

In a circuit breaker with a rotating movable contact device as shown in FIGS. 11 and 12, the breaking distance of the main contact is smaller than the breaking distance of the arcing contact, so the arc of the main contact If it cannot be rapidly transferred to the arc contactor,
In other words, if commutation fails, it will be difficult to shut off.

As shown in equation (5), the circulating current i. What prevents the rapid rise of is the total inductance L of the circuit.

, and what limits the maximum value of the current is the total resistance R of the circuit
It is 8. In the contact device shown in FIGS. 11 and 12, in order to ensure smooth opening and closing operations, the flexible conductor is long and the cross-sectional area is not too large compared to the rated current.

The drawback was that the inductance and resistance were large, and rapid commutation could not be expected.

Accordingly, the main object of the present invention is to provide a contact device in which current is quickly commutated from the main contact to the arc contact when the contact device is opened, and the breaking performance is improved.

Furthermore, another object is to satisfy the following conditions for short-circuiting the main contact and the arc contact in order to achieve the above-mentioned main object.

(1) The short circuit should be made as close to the main contact and the arc contact as possible.

(2) Short circuit resistance should be as small as possible.

(3) Do not interfere with the independent movement of the main contactor and arc contactor.

(4) High contact reliability between the main contact, the shorting piece, and the arc contact.

(5) Do not damage the mechanical strength of the contact device.

(6) Be simple.

[Means for solving problems]

Good commutation is possible if the arc contact circuit and the main contact circuit can be short-circuited as close to the contact as possible and with low resistance. However, since the main contact and the arc contact rotate slightly relative to each other when opening and closing, the mutual displacement must also be followed. In order to short-circuit with low resistance without losing this followability, it is preferable to perform the short circuit near the common axis.

Therefore, according to the invention, a contact device is provided.

A common axis of the main contact and the arc contact is formed by a central axis made of a material having high tensile strength and a bushing made of a material having high electrical conductivity.

It is characterized in that the bushing short-circuits the main contact and the arc contact in a low resistance state.

Other objects, features and advantages of the invention will become apparent from the following detailed description of several embodiments of the invention that are illustrated in the drawings.

〔Example〕

1 to 3 are views showing one embodiment of the present invention, in which FIG. 1 is a plan view, FIG. 2 is a side sectional view showing a closed circuit state, and FIG.
The figure is a side sectional view showing the arc contact just before breaking apart. In the figure, parts that are the same as those of the conventional device in FIGS. 11 and 12 are given the same reference numerals, and differences will be explained.

As shown in FIGS. 1 to 3, in the contact device of the present invention, the common shaft 60 for integrally mounting the movable main contact 7 and the movable arc contact 9 on the contact support device 11 is high. It is formed of a central shaft 3Oa made of tensile strength steel and a bushing 30b made of a highly conductive material such as copper or brass, and the movable main contact 7 and the movable arc contact 9 are short-circuited by the bushing 30b. Each contact 7°9!
: The contact pressure between the bushings 50b is due to the spring 14 of the main contactor.
and the spring 15 of the arc contact. It goes without saying that the movable arc contactor 9 and the bushing 30b may be metal-bonded by soldering or the like.

For example, in the conventional 1600A type circuit breaker mentioned above, a copper pipe with an outer diameter of 10 mm and an inner diameter of 7 mm is attached to the bushing 3.
If this invention is implemented as an ob, a short circuit will be created at the common axis position with a cross-sectional area of 40 mm and a short circuit resistance including contact resistance of 13 μΩ, so the equivalent circuit shown in FIG. 13 will become the equivalent circuit shown in FIG. 4 after implementing this invention. This becomes an equivalent circuit. A circulating current of 1° passes through this short circuit resistor R8H.

In this case, the total resistance R'. , total inductance blo
is R1゜2Ra, +Rao+Ra2+Rm1+Rm2+R
8H"'o-Lac+Lmc, and the internal resistance Rax' Rm3 of the flexible conductor and the interface Xa, lXml are eliminated.

The molded circuit breaker after implementation of this invention is in new condition.

is obtained.

(When formula (3) is illustrated using the data of the four formulas, it is expressed by the ■ curve shown in Figure 5. Point B where the maximum current of the main contact reaches the 920OA line at E21■ is 57μ, sec later, 382 at point A of the conventional device.
The main contact current 1m disappears much earlier than μ and SθC. Also, the resistance R between the arc contacts
As ac increases, the maximum current value of 1° decreases to 92
Even if it is necessary to wait for E to rise without reaching 00A, the condition can always be achieved more quickly than that shown by the 0 curve of the conventional device, which reduces arcing between the main contacts. Great effect.

6 to 8 show other embodiments, FIG. 6 is a plan view, FIG. 7 is a side sectional view in a closed circuit state, and FIG. 8 is a perspective view of essential parts of the arc contactor. The same parts as in the previous embodiment are given the same reference numerals, and the different parts are explained. In the movable arc contact 9, the part sandwiched between the movable main contact 7 is wider than the part protruding forward from the movable main contact. is formed thinly,
Moreover, the flexible conductor 13 connected to the second fixed terminal conductor 2 from one end of the movable arc contactor is omitted. A common shaft 30 that integrally attaches the movable arc contact 9 and the movable main contact 7 to the contact support device 11 has a central shaft 30a and a bushing xo.
In this case, the arc contactor 9 and the bushing 30b are metal-bonded so that a particularly low resistance connection state can be maintained. Such an embodiment is used when it is desired to increase the conductor cross-sectional area of the main contact circuit within the same pole width.

FIG. 9 shows another embodiment A, and the same parts as those in the embodiment shown in FIGS. 1 to 3 are given the same reference numerals, and different parts will be explained.

A movable main contact 6 and a movable arc contact 8 are provided on a movable side contactor 31, and correspond to the movable arc contacts 9 arranged in parallel in the embodiment shown in FIGS. 1 to 3, for example. A movable main contact 6 and a movable arc contact 8 are provided on the movable side contactor 61, which is provided as shown in FIG. As the arc progresses further, the arc contact and all the main contacts 3, 6 come into contact with each other, and as the circuit progresses, in the closed and stationary state, the arc contacts 4, 8 are slightly opened, and all the main contacts 3, 6 are in contact. In addition, when opening, all main contacts 3, 6 open before arc contacts 6, 8, but by the time all main contacts 3, 6 open, arc contact 4° 8 momentarily opens. The contacts are electrically arranged in parallel so that the arc contact 4.8 contacts the arc contact 4.8 and finally opens. In other words, in the closed state, the arc contact 4
, 8 are not in contact because of a gap, and are configured to contact only at the instant of closing and just before opening. Note that this movable side contactor 61 must share the main circuit current in the open state, and the flexible conductor cannot be omitted.

FIG. 10 is a side sectional view showing still another embodiment, in which a first fixed terminal conductor 41 and a second fixed terminal conductor 42 are provided at a distance, and the fixed side contact device is electrically connected. The fixed main contacts 45 and the fixed arc contacts 46 each having the fixed main contacts 43° or the fixed arc contacts 44 arranged in parallel are arranged in parallel with each other, and the fixed arc contacts 46 are provided on both sides. Each contact 45.4 on the fixed side is formed to protrude further forward than the fixed main contact 45.
6 is rotatably supported by a contact support device (not shown) by a common shaft 30 consisting of a central shaft 30a and a bushing 30b. Each contact on the fixed side 45.46
A spring 47, 48 is installed between the main contact and the first fixed terminal conductor 41 to apply contact pressure to the main contact and the arc contact. One end of each contactor 45, 46 on the fixed side and the first fixed terminal conductor 41 are connected by flexible conductors 49 and 50, respectively. On the other hand, a movable contact device 52, which is opened and closed by a member 51 of the opening/closing operation mechanism, is rotatably supported on a support base 53 by a shaft 54, and a movable contact device 55 (fixed main contact 43 and A movable main contact 56 and a movable arc contact 57 are installed so as to be in contact with and separate from the fixed arc contact 44. A flexible conductor 58 connects the movable contact 55 and the second fixed terminal conductor 42. This embodiment In contrast to the embodiment shown in FIGS. 1 to 3 in which the movable contact device is divided into a main contact and an arc contact and arranged in parallel, the fixed contact device is used as a main contact. and an arc contactor.

This does not depart from the basic gist of the invention.

〔Effect of the invention〕

As described above, according to the present invention, a contact device of the same polarity is divided to include a main contact and an arc contact and are electrically arranged in parallel, and each contact is mounted on a contact support device. In a device that is rotatably supported on a common shaft, the common shaft is formed by a central shaft made of a material with high tensile strength and a bushing made of a material with high conductivity, and each contact is short-circuited. It can speed up the commutation from the main contact to the arc contact, reduce arcing between the main contacts, prevent damage to the main contacts due to arc, and have a great effect of improving breaking and switching performance.

[Brief explanation of drawings]

1 to 3 are views showing one embodiment of the contact device of the present invention, in which FIG. 1 is a plan view, FIG. 2 is a side sectional view showing a closed circuit state, and FIG. 3 is an arc contact device. 4 is an electrical equivalent circuit diagram of a molded case circuit breaker embodying this invention, FIG. 5 is a current one-hour characteristic diagram, and FIGS. 6 to 8 are diagrams showing other circuit breakers. Figure 6 is a plan view, and Figure 7 is a diagram showing an embodiment.
The figure is a side sectional view in a closed circuit state, FIG. 8 is a perspective view of the main part of the arc contact, FIG. 9 is a side sectional view of another embodiment, and FIG.
The figure is a side sectional view of another embodiment, FIGS. 11 and 12 are a plan view showing a conventional device and a side sectional view showing a closed circuit state, FIG. 13 is an electrical equivalent circuit diagram of the conventional device, and FIG. FIG. 14 is a similar circuit diagram. In the figure, 1, 2: fixed terminal conductor,
3: Fixed main contact, 4: Fixed arc contact, 5: Movable contact device, 6: Movable main contact. 7: Movable main contact, 8: Movable arc contact, 9: Movable arc contact, 10: Common shaft, 11: Contact support device, 12
, 13: Flexible conductor, 14. +S: Spring, 16: Rotation shaft, 17: Pin, 18: Opening/closing operation mechanism member, 19: Cross bar, 20: Arc extinguishing device, 21: Arc extinguishing plate, 22: Support plate, 30: Common shaft% 30a: Central shaft, 30b: Bushing. 31: Contact, 41, 42: Fixed terminal conductor, 46: Fixed main contact, 44: Fixed arc contact, 45: Fixed main contact, 46: Fixed arc contact, 47° 48: Spring, 49
, 50, 58: flexible conductor, 52: flexible d-side contact device,
53: Support stand, 54: Axis. 55: Movable contact, 56: Movable main contact, 57: Movable arc contact. Patent applicant Terasaki Electric Industry Co., Ltd. Figure 1 Figure 6 Figure 7 Figure 8 Figure 11 Figure 12 Figure 13

Claims (1)

[Scope of Claims] 1. A main contact that can be opened and closed; an arc contact that contacts the main contact in advance when closing the circuit and opens after a delay when the circuit opens; a common shaft on which the contacts are electrically arranged in parallel and rotatably supports each contact; a contact support device on which the common shaft is attached;
spring means each installed to apply pressure between the contact support device, the main contact, and the arc contact in a state of contact; and a second fixed terminal conductor common to one end of the main contact and the arc contact. and a flexible conductor connecting the main contact, wherein the common shaft is formed by a central shaft made of a material with high tensile strength and a bushing made of a material with high conductivity, and the bushing is connected to the main contact. A contact device characterized by short-circuiting arc contacts to a low resistance state. 2. The main contact and the arc contact are movable contact devices formed to be openable and closable by an opening/closing operation mechanism, and the contact corresponding to the movable contact is a fixed contact that is not directly operated by the opening/closing mechanism. The contact device according to claim 1, which is a device. 3. The main contact and the arc contact are fixed side contact devices formed so as not to be directly operated by the opening/closing operation mechanism, and the contacts corresponding to the fixed side contact device are formed so as to be openable/closeable by the opening/closing operation mechanism. The contact device according to claim 1, wherein the contact device is a movable contact device. 4. Claim 1 characterized in that the flexible conductor connecting the arc contactor and the second fixed terminal conductor is omitted.
The contact device according to any one of Items 1, 2, and 3. 5. Any one of claims 1, 2, and 3, characterized in that it is formed by a plurality of contacts, and at least one contact includes both an arc contact and a main contact. Contact device as described in Section.