JPH11120883A - Contact point deterioration preventive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove an oxide film formed on a contact point and sticking dust due to its shock, maintain the contact point in satisfactory condition, and prevent electrical continuity failure by connecting a short-circuit resistance through a changeover switch to the output side of a normally opened contact point of a relay, and making an electric current flow to the short-circuit resistance via opening/closing an operation switch at any time. SOLUTION: A contact point deterioration preventing device 16 is constituted so as to make an electric current flow intermittently to a resistance 20 by opening/closing of an operation switch 18 by switching a short-circuit resistance 20 and the output side by a changeover switch 19. This is connected between control power sources P and N, and when an A contact point 17-1 of a normally opening condition is cleaned, the changeover switch 19 is switched to the B contact point side, and an electromagnetic contactor 14 is put in an unexcited state, and the operation switch 18 is closed, and an electric current is made to flow to the resistance 20 via the A contact point 17-1 . An arc is generated in the A contact point 17-1 together with a short-circuit current by intermittently opening/closing the operation switch. Therefore, an insulating oxide film is separated by a mechanical shock, current-carrying and the arc at opening/ closing time of the A contact point 17-1 , and dust is also removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a relay for opening and closing an electric contact by energizing and de-energizing an electromagnet, and more particularly to a contact deterioration preventing device for preventing a conduction failure of the electric contact which has been kept open for a long period of time.

[0002]

2. Description of the Related Art An electromagnetic relay having the same function as an electromagnetic contactor or an electromagnetic relay for controlling the opening and closing of an electric circuit by an external electric signal. For example, an auxiliary relay has a small conduction current capacity but a small contact resistance for a long time. A structure that has stable contact characteristics and a small increase in contact resistance due to the intrusion of dust from the outside is required to have high contact reliability over a long period of time.

As shown in the side view of FIG. 12A, a general auxiliary relay 1 has an electromagnet 4 on one of a base base 2 and a wiring portion 3 and is attracted to face the electromagnet 4. A movable arm 7 integrally comprising a movable piece 6, a fulcrum 5 serving as a movable center, and an insulator 7a for swinging a movable contact.
Has been arranged.

On the other side of the wiring portion 3, a normally open A movable contact 8 and a normally closed B movable contact 9, which are contacts engaged with the insulator 7 a of the movable arm 7, are provided.
And the A movable contact 8 and the B movable contact 9
The fixed A fixed contact 10 and the fixed B contact 11 are arranged. The A movable contact 8 and the B movable contact 9
The fixed A contact 10 and the fixed B contact 11 are connected to the left contact 12 and the right contact 13 on the wiring portion 3 as shown in the front view of FIG. A pair is provided in parallel.

[0005]

For example, the conductive contact of the contact in the auxiliary relay 1 is characterized in that although the conductive current capacity is small, the contact resistance is small for a long time and stable contact characteristics can be obtained. When the use is for disaster prevention or the like, it does not operate for a long time. However, in such an emergency control circuit that is operated only in an emergency for disaster prevention or the like, the auxiliary relay 1 is not operated for a long time during normal operation of a plant or the like. It is in an environment where the contact resistance of the contact is likely to increase due to the adhesion of a film or dust.

For example, as shown in a circuit configuration diagram of FIG. 13, a sequence circuit using an auxiliary relay 1 in a normal control system has an auxiliary relay 1 having a small conduction current capacity.
, An amplifier circuit is constructed by easily driving the electromagnetic contactor 14 having a large conduction current capacity.

That is, by the closing operation of the A contact 15 which is a command signal, the electromagnet coil 1a of the auxiliary relay 1 is first excited by the control power supplies P and N, and the A contact _1-1 is closed. The closing of the contact A 1 _-1, is excited electromagnetic contactor 14 is controlled power P, by N, by the A contact 14 _-1 large conduction current capacity closed, and outputs an output signal of large current.

[0008] This is but a normal logic operation, if where, since the contact A 1 _-1 auxiliary relay 1 had no operation for a long time, adhered occurs and dust of the insulating film on the contact surfaces In this case, even if the auxiliary relay 1 is excited, the A contact _1-1 becomes defective in conduction, and the electromagnetic contactor 14 is not excited. Thus, the A contact 14 _-1 from becoming inoperative, A contact to A contact 15 is the command signal 14 _-1
This causes a problem that an output signal of a large current is not output from the device.

[0009] Therefore, in the emergency control circuit, if the operation of the auxiliary relay 1 is required once when an accident occurs, the accident that has occurred may become large due to its nature. As a countermeasure against this, conventionally, it has been proposed to prevent a contact failure beforehand by changing various contact shapes and structures to improve the reliability of contact conduction.

An object of the present invention is to provide an operation button at a contact of a relay or the like and an operation switch and a changeover switch for manual or remote operation at a contact circuit,
It is an object of the present invention to provide a contact deterioration preventing device that constantly opens and closes a contact such as a relay in an energized state so as to always maintain a good conduction state of the contact.

[0011]

According to a first aspect of the present invention, there is provided a contact deterioration preventing device comprising a plurality of contacts and an electromagnet, wherein the relay is a normally open contact connected to a control power supply. And a switch for switching between an output circuit and a short-circuit resistor is connected to the output side, and a normally open operation switch is connected between the control power supply and the electromagnet coil.

The changeover switch keeps the output circuit connected to the normally open contact of the relay open, connects the short-circuit resistor, and thereafter repeatedly closes and opens the operation switch. Thereby, the electromagnet coil of the relay is excited and de-energized, and the current due to the short-circuit resistance flows intermittently to the normally open contact, and the current at the time of contact, the arc at the time of separation, and the impact at the time of contact form the contact at the contact. The applied insulating film and the attached dust are removed, thereby preventing the conduction failure of the contacts.

According to a second aspect of the present invention, there is provided a contact deterioration preventing device, wherein a manual operation button is provided on a movable contact of a normally open contact of the relay connected to a control power source in a relay comprising a plurality of contacts and an electromagnet. A switch for switching between an output circuit and a short-circuit resistor is connected to the output side of the normally open contact with an operation button.

The changeover switch keeps the output circuit connected to the normally open contact of the relay open, and connects the short circuit resistor. Thereafter, the manual operation button is repeatedly pressed. Thereby, the electromagnet coil of the relay is excited and de-energized, and the current due to the short-circuit resistance flows intermittently through the normally open contact, and the current at the time of contact, the arc at the time of separation, and the impact at the time of contact form the contact at the contact. The applied insulating film and the attached dust are removed, and the conduction failure of the contacts is prevented.

According to a third aspect of the present invention, in the relay comprising a plurality of contacts and an electromagnet, a manual operation button is provided on each movable contact of two sets of normally open contacts in the relay connected to a control power supply. And an operation switch to a short-circuit resistor and a changeover switch of an output circuit are connected to the output side of the normally open contact with the manual operation button.

With the changeover switch being one normally open contact of the relay, the operation switch for the other normally open contact of the relay is closed to connect a short-circuit resistor, and the manual operation button of the movable contact of the normally open contact is operated. Press repeatedly. As a result, the current due to the short-circuit resistance intermittently flows through the other normally open contact, and the current at the time of contact, the arc at the time of separation, and the impact at the time of contact cause the insulating film formed on the contact and dust attached to the contact. It is removed to prevent poor conduction of the contacts.

Next, the operation switch for the other normally open contact is opened, and the output circuit is switched to the other normally open contact of the relay by a changeover switch to hold the output circuit in a closed state. Close the operation switch and connect the short-circuit resistor.

Thereafter, by repeatedly pressing the manual operation button on the movable contact of the other normally open contact, the insulating coating and dust on the other normally open contact are removed, and the conduction failure of the other contact is reduced. Is prevented. In addition,
During any contact cleaning work, the relay receives the command signal and the electromagnetic coil is excited, so that one or the other normally open contact is closed, so the output circuit can be connected via the changeover switch without any trouble in the contact cleaning work. Works.

According to a fourth aspect of the present invention, in the relay of the third aspect, in the relay comprising a plurality of contacts and an electromagnet, each fixed contact of two sets of normally open contacts in the relay connected to a control power supply. And a switch for short-circuit resistance and a switch for switching an output circuit are connected to the output side of the normally open contact with each manual operation button.

The same operation is achieved by the same procedure as in the third aspect of the present invention, but the normally open contact is opened and closed by repeatedly pressing the manual operation button of the fixed contact of the normally open contact during contact cleaning.

According to a fifth aspect of the present invention, there is provided a contact deterioration preventing apparatus according to the third aspect, wherein in the relay comprising a plurality of contacts and an electromagnet, two sets of each normally open contact in the relay connected to a control power supply are opposed. And a normally open manual short-circuit bar is provided, and an operation switch for a short-circuit resistor and a changeover switch for an output circuit are connected to the output side of each normally open contact.

According to the same procedure as in the third aspect of the present invention, the same operation is achieved, but the manual open short-circuit bar is repeatedly pressed between the movable contact and the fixed contact of the normally open contact during contact cleaning, whereby the normally open circuit is opened. Short and open contacts.

According to a sixth aspect of the present invention, in the relay of the fifth aspect, in the relay comprising a plurality of contacts and an electromagnet, a single manual short-circuit bar for a normally open contact in the relay connected to a control power supply is provided. It is characterized by having. The same operation is achieved by the same procedure as that of the fifth aspect of the present invention. However, when the contacts are cleaned, a single manual short-circuit bar is repeatedly inserted and removed between the normally open contact, the movable contact, and the fixed contact, and the normally open circuit is opened. Short and open contacts.

According to a seventh aspect of the present invention, in the relay comprising a plurality of contacts and an electromagnet, a normally closed contact to an output circuit is provided on an output side of a normally open contact of the relay connected to a control power supply. And an operation switch having a normally open contact to a short circuit resistor and a normally open contact connected between the control power supply and the electromagnet coil.

By closing the operation switch, the normally-closed contact of the operation switch holds the output circuit in the open state,
One normally closed contact connects a short-circuit resistor, and the other normally closed contact excites the electromagnet coil of the relay to close the normally open contact of the relay.

Next, when the operation switch is opened, the normally closed contact of the operation switch closes the output circuit, one normally open contact disconnects the short-circuit resistor, and the other normally open contact disconnects the electromagnetic coil of the relay. Energize and open the normally open contact of the relay. By repeatedly closing and opening the operation switch, the current due to the short-circuit resistance intermittently flows through the normally open contact of the relay, and the current at the time of contact and the arc at the time of separation and the impact at the time of contact are formed at the contact. The insulating film and the attached dust are removed, thereby preventing poor contact at the contacts.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. Note that the same components as those of the above-described related art are denoted by the same reference numerals, and detailed description thereof will be omitted. The first embodiment is directed to claim 1, and as shown in the circuit configuration diagram of FIG.
An A contact 15 which is a command signal and an electromagnet coil 17a of a relay, for example, an auxiliary relay 17 are connected in series, and a normally open circuit is provided between a connection point between the A contact 15 and the electromagnet coil 17a and the control power supply P. Connect the operation switch 18.

[0028] Between more control power P and N, A contact of A contact 17 _-1 a changeover switch 19 of the auxiliary relay 17, and the conduction current capacity with A contact 14 _-1 large output signal, For example, the electromagnetic contactor 14 is connected in series, and the B contact of the changeover switch 19 is connected to the control power supply N via the short-circuit resistor 20.

As shown in the side view of FIG. 2, the auxiliary relay 17 has an electromagnet 4
And a movable arm 7 integrally formed with a movable piece 6 attracted to face the electromagnet 4, a fulcrum 5 serving as a movable center, and an insulator 7a for swinging a movable contact.

On the other side of the wiring portion 3, on the other hand, a normally open A movable contact 8 and a normally closed B movable contact 9, which are contacts engaged with the insulator 7a of the movable arm 7, are provided. A fixed contact 10 and a B fixed contact 11 which are opposed to the movable contact 8 and the B movable contact 9, a left contact 12 and a right contact
Two sets of 13 are arranged in parallel.

Here, one set of the A movable contact 8 and the A fixed contact 10 shown as the right contact 13 corresponds to the A contact _17-1 , and the left contact 12 (not shown) is provided with another contact deterioration preventing device if necessary. Form 16. The above configuration is the same as that of FIG. 12 described above, and shows a case where a short-circuit resistor 20 is installed on the base 2. This short-circuit resistor 20 is provided together with the operation switch 18 and the changeover switch 19 together with the auxiliary relay 17. The operation switch 18 and the changeover switch 19 may be operated remotely instead of manually.

Next, the operation of the above configuration will be described. When the contact deterioration preventing device 16 is employed in an emergency control circuit, the changeover switch 19 is normally set to the A contact side in normal times. Thereby, the closing operation of the A contact 15 which is the command signal excites the electromagnet coil 17a, and the A contact 17 _-1
Operates to close.

The electromagnetic contactor by closing of the A contact 17 _-1
14 is excited by the A contact 14 _-1 large conduction current capacity closed, the output signal of a large current is output. When the contact A, which is a command signal, is opened, the electromagnet coil 17 is opened.
a is de-energized and the A contact _17-1 is opened, whereby the electromagnetic contactor 14 is de-energized, and the A contact 14 having a large conduction current capacity is opened.
_{Since -1} opens, the output signal of the large current stops.

[0034] In case of contact A 17 _-1 auxiliary relay 17 has been placed a long period of time as the open state, to eliminate or an insulating film formed on the A contact 17 _-1, a conduction failure due to adhesion of dust or the like Contact cleaning work to remove the insulating coating and dust etc.
It is carried out periodically or as needed depending on the state of the surrounding atmosphere.

In the contact cleaning operation, first, the changeover switch 19 is temporarily switched from the A contact side to the B contact side, whereby the electromagnetic contactor 14 is de-energized, and the output signal A contact _14-1 is opened. The output signal is stopped as it is. Next, when the operation switch 18 is closed, the electromagnet coil 17a of the auxiliary relay 17 contacts the A contact 15 which is the command signal.
From being energized regardless of the state of, the A contact 17 _-1 flows in short-circuit current A contact 17 _-1 to meet the short-circuit resistor 20 from control power source P and closing operation.

When the operation switch 18 is opened, the electromagnet coil 17a is de-energized and the A contact _17-1 is opened to cut off the short-circuit current. Incidentally, the A contact 17 _-1 when intermittence of the short-circuit current, but arc is generated with the short-circuit current flows commensurate with the time constant of the magnitude and the circuit of the short circuit resistance 20, the magnitude of the short-circuit current and arc, By changing the resistance value of the discharge resistor 20, it can be adjusted appropriately.

[0037] Therefore, by repeating several times the opening and closing operation of the operation switch 18, A contact 17 _-1 and mechanical impact during opening and closing, by energization and generated arc short-circuit current due to an electric disconnection, The attached dust and the like are removed, and the insulating film formed on the contact surface peels off.

As a result, the electrical contact condition on the surface of the A contact _17-1 becomes good, and the poor conduction is eliminated.
Open the operation switch 18 and set the changeover switch 19 to B
By switching from the contact side to the A contact side, the A contact 17 _-1 contact deterioration preventing apparatus 16 and the auxiliary relay 17, to return again to the normal.

In this contact deterioration preventing device 16,
Since the changeover switch 19 and the operation switch 18 are electrically operated, the contact cleaning operation can be performed without being affected by the surrounding atmosphere where the auxiliary relay 17 is installed. Further, by appropriately carrying out the contact cleaning operations, it is possible to maintain the continuity of the A contact 17 _-1 auxiliary relay 17 always healthy, and had without long-term operation, operates only emergency The operation reliability of the sequence circuit formed by the auxiliary relay 17 in the emergency control circuit is improved.

The second embodiment relates to claim 2, wherein
The description of the same components and operations as those in the first embodiment will be omitted, and different portions will be described. As shown in the circuit diagram of FIG. 3, the contact deterioration preventing device 21 includes an A contact 15 and an A contact 22 _-1 which are command signals between the control power supplies P and N.
Electromagnetic coil 22 of auxiliary relay 22 with manual operation button
a in series.

[0041] Furthermore, between the control power P and N, the manual operation button with the auxiliary contact A of the A contact 22 _-1 a changeover switch 19 of the relay 22, and the A contact of the conduction current capacity larger output signal 14 For example, the electromagnetic contactor 14 having _-1 is connected in series, and the B contact of the changeover switch 19 is connected to the control power supply N via the short-circuit resistor 20.

As shown in the side view of FIG. 4, the auxiliary relay 22 has substantially the same configuration as that of FIG. 2, but the movable arm 7 has a normally open A movable contact 8 and a normally closed B movable contact 8. A manual operation button 23 for temporarily opening the A movable contact 8 and the normally closed B movable contact 9 is provided integrally with the insulator 7a engaged with the movable contact 9. The position and shape of the manual operation button 23 are not limited to those shown in FIG. 4, but may be other shapes and positions.

Here, one set of the A movable contact 8 and the A fixed contact 10 shown as the right contact 13 corresponds to the A contact _22-1 , and the left contact 12 (not shown) is provided with another contact deterioration preventing device as necessary. Form 21. The above is substantially the same configuration as in FIG. 2 above, and shows a case where a short-circuit resistor 20 is installed on the basic base 2. This short-circuit resistor 20 is placed separately from the auxiliary relay 22 together with the changeover switch 19. It is good.

Next, the operation of the above configuration will be described. In the contact cleaning operation in the contact deterioration preventing device 21, first, by temporarily switching the changeover switch 19 from the A contact side to the B contact side, the electromagnetic contactor 14 is de-energized, and the output signal A contact _14-1 becomes The stop state of the output signal is maintained with the open operation.

Next, when the manual operation button 23 is pressed in the direction of the white arrow 24, the auxiliary relay 22 changes the A movable contact 8 to the A fixed contact 10
Contact with, B movable contact 9 is separated from the B fixed contact 11, regardless of the state of the A contact 15 is the command signal, the short-circuit current commensurate with the discharge resistance from the control power P flows A contact 22 _-1 . When the manual operation button 23 is released, the A contact _22-1 is opened, and the short-circuit current is cut off.

[0046] Therefore, by repeating several times the pressing and release operation of the manual operation button 23, A contact 22 _-1 and mechanical impact during opening and closing, and energization and generation of short-circuit current due to the electrical disconnection The arc removes the attached dust and the like, and peels off the insulating film formed on the contact surface.

As a result, the electrical contact state on the surface of the A contact _22-1 becomes good, and the poor conduction is eliminated. After this, the release of the manual operation buttons 23, by switching the changeover switch 19 from the B contact side to the A contact side, the A contact 22 _-1 contact deterioration prevention device 21 and the auxiliary relay 22,
It returns to the normal state again.

[0048] By carrying out the contact cleaning operations appropriately, it is possible to maintain the continuity of the A contact 22 _-1 auxiliary relay 22 always healthy, and are in no long-term operation,
The operation reliability of the contact deterioration prevention device 21 formed by the auxiliary relay 22 employed in the emergency control circuit that is operated only in an emergency is improved. In addition, according to the auxiliary relay 22, the contact deterioration preventing device 21 has a small number of components and is simplified, so that wiring work and the like can be reduced.

The third embodiment relates to claim 3, wherein an output signal can be output even during a contact cleaning operation. The description of the same components and operations as in the first embodiment will be omitted, and only the differences will be described. As shown in the circuit diagram of FIG.
The electromagnetic coil 26 of the auxiliary relay 26 with a manual operation button that enables the A contact 15 which is a command signal between the control power sources P and N and the two sets of the A contact _26-1 and the A contact _26-2 to be separately operable.
a in series.

[0050] Furthermore, between the control power P and N, A of one of the A contact 26 _-1 a changeover switch 19 of the auxiliary relay 26
The contact and the short-circuit resistor 20 via the normally open operation switch 27 are connected in series. Also, B contacts of the other contact A 26 _-2 changeover switch 19 of the auxiliary relay 26, and are connected in series with the short-circuit resistance 20 via the normally open operation switch 28, Konmon of the changeover switch 19 The control power supply N is provided, for example, via an electromagnetic contactor 14 having an A contact _14-1 for an output signal having a large conduction current capacity.

The auxiliary relay 26 with the manual operation button is shown in a side view of FIG. 6A and a side view of FIG.
As shown in the front view as viewed in the direction indicated by the arrow in FIG. 5, the fulcrum 5 which is the movable center of the right contact 13 and the movable arm 7 having a manual operation button 23a integrated with an insulator 7a for swinging the movable contact
And a fulcrum 29 serving as a movable center of the left contact 12 and an insulator (not shown) for swinging the movable contact and a manual operation button 23b
Is separated from the movable arm 30, and the movable arm 7 and the movable arm 30 can be operated separately.

Here, one set of the A movable contact 8 and the A fixed contact 10 shown as the right contact 13 corresponds to the A contact _26-1 , and the A movable contact 8 and the A fixed contact 10 of the left contact 12 (not shown).
The set corresponds to the A contact _26-2 . The positions and shapes of the manual operation buttons 23a and 23b are not limited to those shown in FIG. 6, but may be other shapes and positions.

Further, the case where the short-circuit resistor 20 is installed on the basic base 2 as in FIG.
The short-circuit resistor 20 may be provided separately from the auxiliary relay 26 together with the changeover switch 19 and the operation switches 27 and 28, or the changeover switch 19 and the operation switches 27 and 28 may be operated remotely instead of manually. The same operation and effect as those of the auxiliary relay 26 can be obtained even in a configuration in which two electromagnets 4 are provided exclusively for the left contact 12 and the right contact 13 as the auxiliary relay.

Next, the operation of the above configuration will be described. When the contact deterioration preventing device 25 is employed in an emergency control circuit, the changeover switch 19 is normally set to the A contact side in normal times. Thus, the closing operation of the A contact 15 which is the command signal excites the electromagnet coil 26a of the auxiliary relay 26, and the A contact _26-1 and the A contact _26-2 are closed. A contact 26 _-1
Electromagnetic contactor 14 is excited by the closing operation, the output signal of a large current is output by the A contact 14 _-1 large conduction current capacity closed, the influence of closing of this time A contact 26 _-2 Nothing happens.

A contact _26-1 and A contact 26 of auxiliary relay 26
_-2 is in the open state if left for a long time.
The contact cleaning work to remove the insulating film formed on the _26-1 and the A-contact _26-2 , the insulating film for eliminating conduction failure due to the adhesion of dust, etc. It will be carried out at any time depending on the condition.

[0056] For the A contact 26 _-1 for contact cleaning operations, by switching from the temporary A contact side switch 19 switched to the contact B side, the electromagnetic contactor 14 becomes non-excited state, a large conduction current capacity A contact _14-1 is kept open and the output signal is stopped.

In this state, when the operation switch 27 is closed and the manual operation button 23a is pressed in the direction of the white arrow 24, in the auxiliary relay 26, the A movable contact 8 comes into contact with the A fixed contact 10, and the B movable contact 9 becomes apart from B fixed contact 11, regardless of the state of the a contact 15 is the command signal, flows in the a contact 26 _-1 short-circuit current commensurate with the discharge resistance from the control power supply P is via the operation switch 27. Also, A contact 26 _-1 Releasing the manual operation button 23a is open, the short-circuit current is interrupted.

[0058] Thus, the manual operation by repeating button 23a a plurality of times pressing the release operation, A contact 26 _-1 and mechanical shock at the time of opening and closing, the energization of the short-circuit current due to electrical disconnection and generation The arc removes the attached dust and the like, and peels off the insulating film formed on the contact surface. At this time, a backup circuit for the electromagnetic contactor 14 is formed by the A contact _26-2 and the B contact of the changeover switch 19.

[0059] That is, during the cleaning operations of the A contact 26 _-1, the A contact 15 is an instruction signal to operate closed, are electromagnetic coils 26a of the auxiliary relay 26 is energized, the closing of the A contact 26 _-2 The electromagnetic contactor 14 is excited via the B contact of the changeover switch 19. Thereby, the A contact 14 _-1 having a large conduction current capacity is obtained.
Is closed and a large current output signal is output.Accordingly, according to the contact deterioration prevention device 25, even if an emergency occurs during contact cleaning work when applied to an emergency control circuit, there is no problem. The function as a control circuit can be exhibited.

Next, the information on the contact cleaning operations for the A contacts 26 _-2, the changeover switch 19 is switched to the contact A side,
The A contact _26-1 and the A contact of the changeover switch 19 form a backup circuit for the electromagnetic contactor 14.

[0061] The operation switch 28 from the closing operation, by repeating several times the pressing and release operation of the manual operation button 23b, short-circuit current in A contact 26 _-2 through the operation switch 28 and the short circuit resistance 20 is intermittently and mechanical impact to flow, at the time of opening and closing of the a contact 26 _-2 by energizing and generating arc short-circuit current due to an electric disconnection, the adhered dust or the like is removed, formed on the contact surfaces The insulating film thus peeled off. As a result, it is possible to ensure a contact state where good contact is always possible.

The fourth embodiment is a modification of the third embodiment, in which an output signal can be output even during a contact cleaning operation. The description of the same components and operations as those in the first and third embodiments will be omitted, and different portions will be described.

As shown in the circuit diagram of FIG. 7, the contact deterioration preventing device 31 includes a command signal A between the control power sources P and N.
And contacts 15, to connect the electromagnetic coil 32a of the manual operation button with the auxiliary relay 32 to the two sets of A contact 32 _-1 and A contact 32 _-2 and another operable in series. Further, between the control power P and N, one of A contact 32 _-1 and switch A contact of the switch 19 short circuit resistance 20 and via the operation switch 27, the auxiliary relay 32 is connected in series.

[0064] Also, if you are connected in series with the short-circuit resistance 20 via the B contact, and the operation switch 28 of the other A contact 32 _-2 changeover switch 19 of the auxiliary relay 31, Konmon of the changeover switch 19 The control power supply N is provided, for example, via an electromagnetic contactor 14 having an A contact _14-1 for an output signal having a large conduction current capacity.

The auxiliary relay 32 with a manual operation button
As shown in the side view of FIG. 8A and the front view of FIG. 8A as viewed in the direction of the arrow in FIG. 8A, a fulcrum 5 serving as a movable center of the right contact 13 and an insulator 7a for swinging the movable contact. Is separated from the movable arm 7 and the fulcrum 29 which is the movable center of the left contact 12 and the movable arm 30 which is integrated with an insulator (not shown) for swinging the movable contact, and two sets are arranged in parallel. I have. The movable arm 7 and the movable arm
It is configured to be able to operate separately from 30.

Further, the two sets of the left contact 12 and the right contact
At 13, by pressing any of the A fixed contact 10 and the B fixed contact 11 in the direction of the white arrow 24,
Manual operation buttons 33a and 33b are provided so that the contacts are separated from the movable contact 8 and the B movable contact 9.

Here, one set of the A movable contact 8 and the A fixed contact 10 shown as the right contact 13 corresponds to the A contact _32-1 , and one of the A movable contact 8 and the A fixed contact 10 (not shown) of the left contact 12.
Set corresponds to the A contact 32 _-2. The positions and shapes of the manual operation buttons 33a and 33b are not limited to those shown in FIG. 8, but may be other shapes and positions.

Further, the case where the short-circuit resistor 20 is installed on the basic base 2 as in FIG.
The short-circuit resistor 20 may be provided separately from the auxiliary relay 32 together with the changeover switch 19 and the operation switches 27 and 28, or the changeover switch 19 and the operation switches 27 and 28 may be operated remotely instead of manually. The same operation and effect as those of the auxiliary relay 26 can be obtained even if the auxiliary relay is configured such that two electromagnets 4 are provided exclusively for the left contact 12 and the right contact 13.

Next, the operation of the above configuration will be described. When the contact deterioration prevention device 31 is employed in an emergency control circuit, the changeover switch 19 is normally set to the A contact side in normal times. Thereby, the closing operation of the A contact 15 which is the command signal excites the electromagnet coil 32a, and the A contact 32 _-1
And A contact 32 _-2 operated closed. Electromagnetic contactor 14 is excited by the closing of contact A 32 _-1, the A contact of a large conduction current capacity
14 _-1 the output signal of a large current is output by the closing, this time affected by closing of contact A 32 _-2 no nothing.

[0070] For the A contact 32 _-1 for contact cleaning operations, by switching from the temporary A contact side switch 19 switched to the contact B side, the electromagnetic contactor 14 becomes non-excited state, a large conduction current capacity A contact _14-1 is kept open and the output signal is stopped.

In this state, when the operation switch 27 is closed and the manual operation button 33a is pressed in the direction of the white arrow 24, in the auxiliary relay 32, the A fixed contact 10 contacts the A movable contact 8 and the B fixed contact 11 Is separated from the B movable contact 9 and the control power P
, A short-circuit current corresponding to the discharge resistance value flows through the operation switch 27 to the A contact _32-1 . In addition, the manual operation button 33a
Is released, the A contact _32-1 is opened, and the short-circuit current is cut off.

[0072] Thus, the manual operation by repeating button 33a a plurality of times pressing the release operation, A contact 32 _-1 and mechanical shock at the time of opening and closing, the energization of the short-circuit current due to electrical disconnection and generation The arc removes the attached dust and the like, and peels off the insulating film formed on the contact surface. Note At this time, the B contact of the A contact 32 _-2 and changeover switch 19, a backup circuit for the electromagnetic contactor 14 is formed.

[0073] Therefore, during the cleaning work of the A contact 32 _-1,
When the contact A, which is the command signal, closes, the electromagnetic coil
The 32a is energized A contact 32 _-2 closing, electromagnetic contactor 14 is excited via the B contact of the changeover switch 19.
Accordingly, since the A contact 14 _-1 large conduction current capacity produce an output signal of large current and closing operation, according to the present contact deterioration prevention device 31, the contact cleaning in case of applying the emergency control circuit During the operation, the function as the control circuit can be exhibited without any trouble even if an emergency occurs.

Next, the information on the contact cleaning operations for the A contact 32 _-2, the changeover switch 19 is switched to the contact A side,
The A contact _32-1 and the A contact of the changeover switch 19 form a backup circuit for the electromagnetic contactor 14.

[0075] The operation switch 28 from the closing operation, manual operation by repeating button 33b several times pressing the release operation, short-circuit current in A contact 32 _-2 through the operation switch 28 and the short circuit resistance 20 is intermittently and mechanical impact to flow, at the time of opening and closing of the a contact 32 _-2 by energizing and generating arc short-circuit current due to an electric disconnection, the adhered dust or the like is removed, formed on the contact surfaces The insulating film thus peeled off. As a result, it is possible to ensure a contact state where good contact is always possible.

The fifth embodiment is a fifth or sixth embodiment.
In the modification of the third embodiment, an output signal can be output even during a contact cleaning operation. The description of the same components and operations as those in the first and third embodiments will be omitted, and different portions will be described.

[0077] As shown in the circuit diagram of FIG. 9, an A contact 15 contacts the deterioration prevention device 34 is an instruction signal between the control power P and N, 2 sets of A contact 35 _-1 and A contact 35 _- the electromagnetic coil 35a of the auxiliary relay 35 with the manual operation _{button 2} was another operable connected in series. Further, the control power supply P
And between N, the auxiliary relay one of the short-circuit resistance 20 via contact A, and a normally open operation switch 27 of the A contact 35 _-1 and changeover switch 19 35 is connected in series.

[0078] Also, if you are connected in series with the short-circuit resistance 20 via the other A contact 35 _-2 of the switch 19 B contacts and normally open operation switch 28 of the auxiliary relay 35, the changeover switch 19 of Konmon has an a contact 14 _-1 conduction current capacity larger output signal, for example, an electromagnetic contactor 14
Is connected to the control power supply N via the.

As shown in the side view of FIG. 10, the auxiliary relay 35 includes a movable arm 7 integrally formed with a fulcrum 5 serving as a movable center as a right contact 13 and an insulator 7a for swinging the movable contact. A fulcrum 29 serving as a movable center of the left contact 12 not to be used and a movable arm 30 integrally formed with an insulator (not shown) for swinging the movable contact are separated, and two sets are arranged in parallel to form the movable arm 7 and the movable arm 30. And can operate separately.

[0080] Here corresponds to A movable contact 8 and 1 set the A contact 35 _-1 A fixed contact 10, shown as the right contacts 13, one of A movable contact 8 and A fixed contact 10 (not shown) of the left contact 12
The set corresponds to the A contact _35-2 .

The auxiliary relay 35 has an A contact 3
The A contacts 35 _-1 and 35 _-2 are inserted between the movable contact 8 and the A fixed contact 10 between the movable contact 8 and the A fixed contact 10 corresponding to 5 _-1 and 35 _-2. Manual short-circuit bar with a conductor short-circuiting piece 36 at the tip of the electrical insulator, each short-circuiting
37a and 37b are provided (claim 5). The manual shorting bars 37a and 37b are separately provided as separate components without being provided in the auxiliary relay 35 (claim 6).

Further, the case where the short-circuit resistor 20 is installed on the basic base 2 as in the case of FIG.
The short-circuit resistor 20 may be provided separately from the auxiliary relay 34 together with the changeover switch 19 and the operation switches 27 and 28, or the changeover switch 19 and the operation switches 27 and 28 may be operated remotely instead of manually.

Next, the operation of the above configuration will be described. When the contact deterioration preventing device 34 is employed in an emergency control circuit, the changeover switch 19 is normally set to the A contact side in normal times. As a result, the closing operation of the A contact 15 which is the command signal excites the electromagnet coil 35a of the auxiliary relay 35, and the A contact _35-1 and the A contact _35-2 close. A contact 35 _-1
Electromagnetic contactor 14 is excited by the closing operation, the output signal of a large current is output by the A contact 14 _-1 large conduction current capacity closed, the influence of closing of this time A contact 35 _-2 Nothing happens.

[0084] For the A contact 35 _-1 for contact cleaning operations, by switching from the temporary A contact side switch 19 switched to the contact B side, the electromagnetic contactor 14 becomes non-excited state, a large conduction current capacity A contact _14-1 is kept open and the output signal is stopped. In this state, the operation switch 27 is closed, and the manual short-circuit bar 37a is moved to the white arrow.
When pressed in the 24 direction, the A fixed contact 10 and the A movable contact 8 are electrically short-circuited in the auxiliary relay 35, and the A contact _35-1 becomes conductive.

[0085] Thus, regardless of the state of the A contact 15 which is a command signal, it flows in the A contact 35 _-1 short-circuit current commensurate with the discharge resistance from the control power supply P via the operation switch 27. Also, manual shorting bar 37a release the A contact 35 _-1 since returning to the open circuit state, the short-circuit current is interrupted.

[0086] Thus, the manual shorted by repeating bar 37a a plurality of times pressing the release operation, A contact 35 _-1 and mechanical shock at the time of opening and closing, the energization of the short-circuit current due to electrical disconnection and generation The arc removes the attached dust and the like, and peels off the insulating film formed on the contact surface. At this time, a backup circuit for the electromagnetic contactor 14 is formed by the A contact _35-2 and the B contact of the changeover switch 19.

[0087] For this, during the cleaning operations of the A contact 35 _-1, the A contact 15 is an instruction signal to operate closed, the electromagnet coil 35a is excited by the closing of the A contact 35 _-2, changeover switch The electromagnetic contactor 14 is excited via the 19 B contacts. Accordingly, since the A contact 14 _-1 large conduction current capacity produce an output signal of large current and closing operation, according to the present contact deterioration prevention device 34, the contact cleaning in case of applying the emergency control circuit During the operation, the function as the control circuit can be exhibited without any trouble even if an emergency occurs.

Next, the information on the contact cleaning operations for the A contact 35 _-2, the changeover switch 19 is switched to the contact A side,
The A contact _35-1 and the A contact of the changeover switch 19 form a backup circuit for the electromagnetic contactor 14.

[0089] The operation switch 28 from the closing operation, manually shorting bar 36b pressing the by repeating several times the release operation, short-circuit current in A contact 35 _-2 through the operation switch 28 and the short circuit resistance 20 is intermittently to flow, and mechanical impact this the a contact 35 _-2 when opening and closing, by energization and generated arc short-circuit current due to an electric disconnection, the adhered dust or the like is removed, formed on the contact surfaces The insulating film thus peeled off. As a result, it is possible to ensure a contact state where good contact is always possible.

Further, the manual short-circuit bars 37a and 37b, which are separately provided as separate parts, are connected to the A-contact _35-1 or A-contact of the auxiliary relay 35.
Auxiliary relay for 35 _-2
The insulating film formed on the surface of the normally open contact in 35 is peeled off, and the attached dust and the like can be removed. Note that the manual short-circuit bars 37a, 37b can be attached to the auxiliary relay 35 by forming the manual short-circuit bars 37a, 37b as a single component.
Since there is no need to install b, a general auxiliary relay can be used as it is.

The sixth embodiment is based on claim 7.
The description of the same components and operations as those in the first embodiment will be omitted, and different portions will be described. As shown in the circuit diagram of FIG. 11, the contact deterioration preventing device 38 includes an A contact 15 which is a command signal between the control power sources P and N, and an auxiliary relay.
17 are connected in series and an operation switch 39 is provided, and the normally open A of the operation switch 39 is provided between the control power supply P and the connection point between the A contact 15 and the electromagnetic coil 17a.
Connecting contact 39 _-1.

[0092] Further between the control power P and N, the A contacts of a normally closed contact B 39 _-2 and conduction current capacity larger output signal of the A contact 17 _-1 an operation switch 39 of the auxiliary relay 17
14 _-1 with a, for example, with connecting electromagnetic contactor 14 in series, a normally open contact A of one more of the operation switch 39
_39-3 is connected to the control power supply N via the short-circuit resistor 20.

Here, one set of the A movable contact 8 and the A fixed contact 10 shown as the right contact 13 shown in FIG.
Corresponds to _-1, to form another contact deterioration prevention device 38 as necessary for the left contact 12, not shown. The above configuration is the same as that of FIG. 12 described above. Even if the short-circuit resistor 20 is installed on the base 2, it may be placed separately from the auxiliary relay 17 together with the operation switch 39, or the operation switch 39 may be manually operated. Alternatively, the remote operation may be performed.

Next, the operation of the above configuration will be described. When the contact deterioration preventing device 38 is employed in an emergency control circuit, the A-contact 15 which is the command signal is normally closed by the closing operation of the electromagnet coil 17a of the auxiliary relay 17 in a normal state.
Is excited, and the A contact _17-1 closes.

[0095] electromagnetic contactor by closing of the A contact 17 _-1
14 is excited by the A contact 14 _-1 large conduction current capacity closed, the output signal of a large current is output. When the contact A, which is a command signal, is opened, the electromagnet coil 17 is opened.
a is de-energized and the A contact _17-1 is opened, whereby the electromagnetic contactor 14 is de-energized, and the A contact 14 having a large conduction current capacity is opened.
_{Since -1} opens, the output signal of the large current stops.

For the contact cleaning operation, the operation switch 39
When temporarily pressed in the direction of the white arrow 24, the electromagnetic contactor 14 B contacts 39 _-2 to open becomes non-excited state, the output signal A
The contact _14-1 keeps the output signal stopped while keeping the open operation. Also, the A contact 39 _-1 A contact 17 _-1 since the electromagnet coil 17a is closed and is energized regardless of the state of the A contact 15 is the command signal is closing operation, further, the A contact 39 _-3 There since the closed, short-circuit current from the control power P commensurate with a short circuit resistance 20 flows to the a contact 17 _-1.

[0097] Next, when releasing the operation switch 39, the A contact 39 _-1, 39 _-3 and B contact 39 _-2 closed while open, the electromagnetic coil 17a is A contact 17 _-1 becomes deenergized open operation As a result, the short-circuit current is interrupted. Therefore, the operation switch
By repeating several times the pressing and release operation 39, A contact 17 _-1 and mechanical impact during opening and closing, by energization and generated arc short-circuit current due to an electric disconnection, adhering dust or the like removed At the same time, the insulating coating formed on the contact surface peels off.

Thus, it is possible to secure a contact state in which good contact is always possible. Further, by maintaining the operation switch 39 in the open state, A contact 17 _-1 contact deterioration preventing apparatus 38 and the auxiliary relay 17, to return again to the normal. In the above embodiments, the auxiliary relay has been described as an example of the relay. However, the present invention is not limited to the auxiliary relay, but may be applied to various electromagnetic relays, electromagnetic contactors, and the like. Accordingly, it is possible to secure a contact state in which good contact is always possible.

[0099]

As described above, according to the present invention, in a relay that is not operated for a long period of time, the generation of an insulating film and the adhesion of dust, which may cause a malfunction due to an increase in the contact resistance of a normally open contact, are matched to the installation environment. By forcibly operating the contacts of the relay in an energized state at appropriate intervals, the deterioration of the contacts can be easily prevented. As a result, the reliability of the relay used for the emergency control circuit that operates only in an emergency without operating for a long period of time, especially for disaster prevention of the plant, etc., becomes higher, and the reliability of the emergency control circuit and the plant Safety is improved.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of a contact deterioration preventing device according to a first embodiment of the present invention.

FIG. 2 is a side view of the auxiliary relay according to the first embodiment of the present invention.

FIG. 3 is a circuit configuration diagram of a contact deterioration preventing device according to a second embodiment of the present invention.

FIG. 4 is a side view of an auxiliary relay according to a second embodiment of the present invention.

FIG. 5 is a circuit configuration diagram of a contact deterioration preventing device according to a third embodiment of the present invention.

FIG. 6 is an auxiliary relay according to a third embodiment of the present invention;
(A) is a side view, (b) is an arrow front view in (a).

FIG. 7 is a circuit configuration diagram of a contact deterioration preventing device according to a fourth embodiment of the present invention.

FIG. 8 is an auxiliary relay according to a fourth embodiment of the present invention;
(A) is a side view, (b) is an arrow front view in (a).

FIG. 9 is a circuit configuration diagram of a contact deterioration preventing device according to a fifth embodiment of the present invention.

FIG. 10 is a side view of an auxiliary relay according to a fifth embodiment of the present invention.

FIG. 11 is a circuit configuration diagram of a contact deterioration preventing device according to a sixth embodiment of the present invention.

FIG. 12 shows a conventional auxiliary relay, wherein (a) is a side view,
(B) is a front view taken in the direction of the arrow in (a).

FIG. 13 is a circuit configuration diagram using a conventional auxiliary relay.

[Explanation of symbols]

₁ , 17, 35 ... auxiliary relay, 1 _-1 , 14 _-1 , 17 _-1 , 22 _-1 , 26
_-1 , 26 _-2 , 32 _-1 , 32 _-2 , 35 _-1 , 35 _-2 , 39 _-1 , 39 _-3 ... A contact (normally open circuit), 1a, 17a, 22a, 26a, 32a, 35a
... Electromagnetic coil, 2 ... Basic base, 3 ... Wiring part, 4 ...
Electromagnets, 5, 29: fulcrum of movable center, 6: movable piece, 7, 30
... Movable arm, 7a ... Insulator, 8 ... A movable contact, 9 ... B
Movable contact, 10 fixed A contact, 11 fixed B contact, 12 left contact, 13 right contact, 14 electromagnetic contactor, 15 A contact of command signal, 16, 21, 25, 31, 34, 38 … Contact deterioration prevention device,
18, 27, 28, 39 ... operation switch, 19 ... changeover switch,
20: short-circuit resistance, 22, 26, 32: auxiliary relay with manual operation button, 23, 23a, 23b, 33a, 33b: manual operation button, 24: white arrow (pressing direction), 36: short-circuit piece, 37a, 37b
... Manual short-circuit bar, 39 _-2 ... B contact (normally closed), P, N ...
Control power supply.

Claims (7)

[Claims] 1. A relay comprising a plurality of contacts and an electromagnet, wherein a switch for switching between an output circuit and a short-circuit resistor is connected to an output side of a normally open contact of the relay connected to a control power source, and the control power source and the electromagnet coil are connected. A contact deterioration prevention device, characterized in that a normally open operation switch is connected during the operation. 2. A relay comprising a plurality of contacts and an electromagnet, wherein a manually operated button is provided on a movable contact of a normally open contact of the relay connected to a control power source, and an output is provided to an output side of the normally open contact with the manually operated button. A contact deterioration preventing device, wherein a switch for switching between a circuit and a short-circuit resistor is connected. 3. A relay comprising a plurality of contacts and an electromagnet, wherein a manual operation button is provided at each movable contact of two sets of normally open contacts in the relay connected to a control power source, and the normally open contact with each manual operation button is provided. An operation switch for short-circuit resistance and a changeover switch of an output circuit are connected to the output side of the contact point deterioration prevention device. 4. A relay comprising a plurality of contacts and an electromagnet, wherein a manual operation button is provided at each fixed contact of two sets of normally open contacts in the relay connected to a control power source, and the normally open contact with each manual operation button is provided. 4. The contact deterioration preventing device according to claim 3, wherein an operation switch for a short-circuit resistor and a changeover switch for an output circuit are connected to the output side of the contact. 5. A relay comprising a plurality of contacts and an electromagnet, wherein a normally open manual short-circuit bar is provided to face each of the two sets of normally open contacts in the relay connected to a control power source, and 4. The contact deterioration preventing device according to claim 3, wherein an operation switch for a short-circuit resistor and a changeover switch for an output circuit are connected to the output side. 6. The contact deterioration preventing device according to claim 5, wherein the relay comprising a plurality of contacts and an electromagnet is provided with a single manual short-circuit bar for a normally open contact in the relay connected to a control power supply. 7. A relay comprising a plurality of contacts and an electromagnet, wherein a normally closed contact to an output circuit, a normally open contact to a short circuit resistor, and a control power supply are provided on the output side of the normally open contact of the relay connected to a control power supply. An apparatus for preventing contact deterioration comprising an operation switch having a normally open contact connected between electromagnet coils.