JPH09284997A - Relay protection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress contact defects such as a transition phenomenon, welding, abnormal wear, increase of a contact resistance, etc., of the contact of a relay. SOLUTION: A load relay 3 through which an AC power supply 2 for the driving of a load 1 is supplied to or cut off from the load 1 is connected in series to the load 1. A rush current which is induced immediately after the load relay 3 is closed is limited by a limiting resistor 4. A control relay 5 which is closed after the contact of the load relay 3 is closed and the current is in a steady state is connected in parallel to the resistor 4 and a microcomputer 6 which controls the opening/closing operations of the load relay 3 and the control relay 5 are provided. With this constitution, regardless of the variation in operation response time of the contact of the load relay 3, the rush current can be suppressed and hence the contact defects can be suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a relay protection device such as an electronic component or a mechanical contact relay for supplying / shutting off an AC power source for driving a load.

[0002]

2. Description of the Related Art Electronic components and mechanical contact relays that supply and cut off AC power for driving loads such as inductive loads are known as contact materials, voltage and current values applied to the contacts (especially, voltage at the time of making and breaking, Current waveform), load type, switching frequency,
It is a component with a limited life that is significantly affected by the surrounding atmosphere, contact type, and the bounce phenomenon of contact opening / closing speed, and causes contact defects such as contact transfer phenomenon, welding, abnormal wear, and increased contact resistance.

Conventionally, a circuit of an electronic component / mechanical contact relay for supplying / interrupting an AC power source for driving a load of this type has generally been constructed as shown in Japanese Patent Laid-Open No. 4-298925.

The structure will be described below with reference to FIG. As shown in the figure, an AC power supply 102 for driving the load 101 connected in series to the load 101, and a load relay 103 for supplying / disconnecting the AC power supply 102.
Is connected, the relay drive unit 104 uses the load waveform at various operation timings set by the relay operation timing setting unit 106 based on the zero-cross point at the rising time of the voltage waveform detected by the voltage waveform rising detection unit 105. It was driving the relay 103. Then, the relay operation detecting unit 107 detects the time when the contact of the relay is closed, and the optimum operation timing selecting unit 108 detects and compares the current value at the contact closing time at each operation timing, and compares the minimum current value. Is selected as the optimum operation timing, and the optimum operation timing storage unit 10 is selected.
No. 9, and when the load relay 103 is operated thereafter, the load relay 103 is driven at the optimum operation timing to reduce the inrush current.

[0005]

In the case of the conventional method of detecting the current value and driving the load relay 103 at the timing when the current value is the minimum, the reading value of the current value detected by the detection circuit is obtained. Error and variations in the operation response time of the load relay 103 itself may not always close the relay contact of the load relay 103 at the optimum timing, or when the relay contact is closed at the optimum timing. Also, since the inrush current is generated,
In the future, there was a problem that contact defects such as contact transfer phenomenon, welding, abnormal wear, and increase in contact resistance are likely to occur.

The present invention solves the above-mentioned conventional problems, and provides a relay protection device capable of suppressing a contact failure such as a relay contact transfer phenomenon, welding, abnormal wear, and increase in contact resistance. The first purpose is to provide.

A second object is that the current detecting means for detecting the load current flowing through the load can suppress contact failure such as transition phenomenon of relay contacts, welding, abnormal wear and increase of contact resistance. It is to provide a relay protection device.

A third object of the present invention is to provide a relay protection device capable of notifying the standard of replacement maintenance time because it is difficult to estimate the life of the load relay contact in the case of an external load connected at the time of construction. To do.

A fourth object of the present invention is to provide a relay protection device capable of notifying the service life of an actual load in the case of an external load connected at the time of construction.

A fifth object is to warn in advance that the operation of the equipment will be incomplete due to the welding of the load relay contact, and prevent the equipment from becoming unusable until maintenance such as parts replacement. It is to provide a relay protection device which can be prevented.

A sixth object of the present invention is to provide a relay protection device which can prevent the load relay contact from being oxidized and causing conduction failure.

[0012]

In order to achieve the above object, a relay protection device of the present invention comprises a resistor for limiting an inrush current generated immediately after a contact of a load relay is closed,
The contact of the load relay is closed in parallel with this resistance,
A control relay that closes its contacts after the load current becomes a steady current, and a microcomputer that controls the opening and closing operations of the load relay and the control relay are connected to the load and flow to the load. It is configured to limit the current.

According to the present invention, the inrush current is suppressed regardless of the variation in the operation response time of the contacts of the load relay,
(EN) A relay protection device capable of suppressing contact failure such as contact transfer phenomenon, welding, abnormal wear, and increase in contact resistance of a load relay.

Another means is to detect the load current value flowing in the load, and to control the opening / closing operation of the load relay and the control relay based on the load current value detected by the current detecting means. Is provided, and the rush current flowing through the load is limited by the load current value.

According to the present invention, even when the generation time of the inrush current is longer than the normal time, the inrush current flowing through the load relay contact can be suppressed, and the transition phenomenon of the contact of the load relay, welding, A relay protection device capable of suppressing contact failure such as abnormal wear and increase in contact resistance is obtained.

Another means is that the microcomputer estimates the contact life of the load relay based on the load current state from the current detecting means and displays the number of times of life.

According to the present invention, it is possible to obtain a relay protection device capable of giving an indication of the replacement time of the load relay due to the external load connected at the time of construction.

Another means is that the microcomputer always stores in the nonvolatile memory the contact lifespan of the load relay and the actual opening / closing count of the load relay depending on the load current state from the current detecting means. The microcomputer determines that the life is approaching based on the difference in the cumulative number of times of opening and closing, and displays it.

According to the present invention, it is possible to obtain a relay protection device capable of estimating the life of a load relay due to an external load connected at the time of construction and notifying the contact life depending on the actual frequency of use.

Another means is to judge a slight welding by displaying a load relay contact closing signal from the microcomputer and a time difference when the load relay contact is actually closed, and display a warning.

According to the present invention, it is possible to obtain a relay protection device capable of preventing the load relay contact from being defectively welded to cause the operation of the device to be incomplete and the device to be unusable.

In another means, when the load current flowing through the load is very small, a resistor and a control relay connected in parallel with the load force a current to flow through the contact of the load relay. It is a thing.

According to the present invention, it is possible to obtain the relay protection device capable of preventing the conduction failure due to the oxidation of the load relay contact which occurs at the time of the minute current.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, an AC power supply for driving a load connected in series to a load, a load relay for supplying / disconnecting the AC power supply, and a contact of the load relay are closed. And a resistor that limits the inrush current that occurs immediately after the contact, and the control relay that closes the contact of the load relay in parallel with this resistance and closes the contact after the load current becomes a steady current, A load relay and a microcomputer for controlling the opening / closing operation of the control relay are provided, and the resistor is connected to the load to limit the inrush current flowing to the load. It has an effect of preventing defective welding of the contacts of the relay.

Embodiments of the present invention will be described below with reference to the drawings.

[0026]

【Example】

(Embodiment 1) As shown in FIG. 1, an AC power supply 2 for driving a load 1 is connected in series to a load 1, and a load relay 3 for supplying and shutting off the AC power supply 2 is provided. Three
Is connected to the resistor 4 for limiting the inrush current generated immediately after closing, and the contact of the load relay 3 is closed in parallel with the resistor 4.
A control relay 5 that is closed after a steady current is reached and a microcomputer 6 that controls the opening and closing operations of the load relay 3 and the control relay 5 are provided.

In the above structure, when the AC power supply 2 is applied to the load 1, the contact of the load relay 3 is first closed by a command from the microcomputer 6,
When the contact of the load relay 3 is closed, the rush current that should originally occur is suppressed by the resistor 4, so that no current exceeding the steady-state current value flows in the load relay 3. After that, after an arbitrary time has elapsed after the generation time of the inrush current, the contact of the control relay 5 is closed by an instruction from the microcomputer 6 so that the inrush current is not generated and the load 1 is a regular AC power supply voltage. Can be applied.

As described above, according to the relay protection device of the first embodiment of the present invention, the resistor for limiting the inrush current is connected to suppress the inrush current generated immediately after the contact of the load relay is closed. Therefore, it is possible to suppress contact failure such as transition phenomenon of relay contacts, welding, abnormal wear, and increase in contact resistance.

In the embodiment, the example of the configuration of the connection configuration of the load 1, the AC power supply 2, the load relay 3 and the resistor 4 shown in FIG. 1 has been described, but after the inrush current is suppressed by the resistor 4, the load The means for applying a regular AC power supply voltage to the load 1 by closing the contacts of the relay 3 for use has, for example, a circuit configuration in which a control relay and a resistor connected in series are connected in parallel with the load relay. If the inrush current can be suppressed, the circuit configuration other than that shown in FIG.

(Embodiment 2) As shown in FIG. 2, a current detecting means 7 for detecting the value of the load current flowing through the load 1 is provided, and the load relay 3 and the load relay 3 are detected based on the load current value detected by the current detecting means 7. A microcomputer 6A is provided so as to control the opening / closing operation of the control relay 5.

In the above structure, the current detecting means 7 detects the value of the current flowing through the load 1, so that the load relay 3
Even if the time of inrush current generated immediately after closing the contact is longer than the normal time, the contact of the control relay 5 should be closed by a command from the microcomputer 6A during the steady state after the inrush current. Is possible,
This means that a regular AC power supply voltage can be applied to the load 1 without generating an inrush current.

As described above, according to the relay protection apparatus of the second embodiment of the present invention, the control means for detecting the load current flowing in the load closes the contact of the load relay for the first time after the load current becomes the steady current. Since the relay is closed, even when the time of the inrush current generated immediately after the contact of the load relay is closed is longer than the normal time, the transition phenomenon of the contact of the load relay, welding, Abnormal wear,
A contact failure such as an increase in contact resistance can be suppressed.

In the embodiment, the protection of the relay by suppressing the inrush current has been described, but the protection of the device from the abnormal large current due to the fan motor lock or the like can be similarly protected.

(Embodiment 3) As shown in FIG. 3, a current detecting means 7 for detecting a load current flowing through a load 1 and a microcomputer 6 for controlling contact opening / closing of a load relay 3 are provided.
Based on B and the current value from the current detection means 7, there is provided a display means 8 for displaying the estimated life of the load relay 3 contact from the microcomputer 6B.

In the above structure, the microcomputer 6B is provided with the load relay 3 detected by the current detecting means 7.
The load current immediately after the contact is closed, that is, the inrush current and the load current after a certain time has elapsed after the contact is closed, that is, the value of the steady current, the stored inrush current of the load relay 3 and the number of contact switching lifespan at the steady current are stored The number of times of life is estimated and displayed on the display means 8.

As described above, according to the relay protection apparatus of the third embodiment of the present invention, it is possible to inform the user of the timing of replacement of the load relay 3 due to the external load connected at the time of construction.

(Embodiment 4) As shown in FIG. 4, an AC power supply 2 for driving the load 1 connected in series to the load 1 and a load relay 3 for supplying and shutting off the AC power supply 2 are provided. A current detecting means 7 for detecting the load current flowing through the load 1, a microcomputer 6C for controlling the opening and closing of the contacts of the load relay 3, and a non-volatile memory 9 for storing the data of the microcomputer 6C.
And the load relay 3 from the microcomputer 6C
A display means 8A for displaying the life status of the contact is provided.

In the above structure, the microcomputer 6C uses the values of the inrush current immediately after the contact of the load relay 3 is closed and the steady-state current after the contact is closed detected by the current detecting means 7 to store the load relay 3 stored in advance. The number of contact opening / closing lives at the inrush current and the steady current is estimated, and the number of lifespan is stored in the nonvolatile memory 9. After that, the microcomputer 6C causes the nonvolatile memory 9 to store the cumulative number of opening / closing times each time the load relay 3 is opened / closed. Then, the microcomputer 6C determines that the contact life of the load relay 3 is approaching when the difference between the total number of times of opening and closing the contacts stored in the nonvolatile memory 9 and the current number of times of opening and closing is less than a certain value, and the display means Display on 8A.

As described above, according to the relay protection apparatus of the fourth embodiment of the present invention, it is possible to estimate the life of the load relay 3 due to the external load connected at the time of construction and inform the contact life according to the actual frequency of use. it can.

In the embodiment, the actual load relay 3
The non-volatile memory 9 was used to prevent the total number of switches from being erased due to a power failure or the like, but a memory backup means may be used as a countermeasure against a power failure of the microcomputer. Does not occur.

(Embodiment 5) As shown in FIG. 5, the AC power supply 2 is supplied to a load 1 connected in series to the AC power supply 2.
A load relay 3 for shutting off is provided, and a current detection means 7 for detecting a load current supplied to the load 1 and a relay control signal for opening and closing a contact of the load relay 3 are output to output the current detection means 7 Is provided with a microcomputer 6D to which a load current value from the microcomputer 6D is transmitted, and warning display means 10 for displaying a warning according to information from the microcomputer 6D is provided. As shown in FIG. A timer means 11 is provided which starts by a relay control signal for closing the contact of the relay 3 and stops by the load current value transmitted by the current detecting means 7. The timer value 12 of the timer means 11 and the load from the microcomputer 6D are provided. The initial value 13 of the time when the contact of the load relay 3 is actually closed from the contact close signal of the relay 3 for load Comparing comparison means 14 is provided, and when a delay of a certain set value or more occurs, the information is transmitted to the warning display means 10, and it is determined that slight welding has occurred at the contact of the load relay 3, and a warning is displayed as a warning. The display is made on the means 10.

In the above structure, when the load 1 is driven, the AC power supply 2 is supplied to the load 1 by transmitting a relay control signal from the microcomputer 6D to close the contact of the load relay 3 to the load relay 3. It

At this time, the timer means 11 is started by the relay control signal from the microcomputer 6D for closing the contact of the load relay 3, and the contact of the load relay 3 is actually closed, and when the load current flows, the The load current is detected by the current detection means 7, and the detected load current value is transmitted to the microcomputer 6D to stop the timer means 11 and set the count time to the timer value 12. The timer value 12 when the load relay 3 is first driven from the microcomputer 6D with this timer value 12 is stored in the microcomputer 6D as an initial value 13. Then, each time the load relay 3 is driven, the timer value 12 and the initial value 1
3 is compared by the comparison means 14, and the timer value 12 and the initial value 1
The time difference of 3 is detected. When the detected time difference becomes equal to or larger than the preset time difference, the microcomputer 6D determines that the micro-welding has occurred in the load relay 3, transmits the information to the warning display means 10, and displays the warning.

As described above, according to the relay protection apparatus of the fifth embodiment of the present invention, when the contacts of the load relay 3 repeatedly supply and disconnect the AC power supply 2 to the load 1 (open and close the contacts), The contact failure of the load relay 3 is detected in the slight welding step before the contact deterioration of the relay 3 due to the rush current flowing at the moment when the contact of the relay 3 is closed, and the welding operation becomes incomplete. This can be warned in advance to prevent the device from becoming unusable until maintenance such as component replacement.

In this embodiment, the initial value 13 is stored inside the microcomputer 6D, but even if a non-volatile storage means is provided outside the microcomputer 6D, there is no difference in the operation and effect.

(Embodiment 6) As shown in FIG. 7, a load relay 3 for supplying / cutting off the AC power supply 2 is provided to a load 1 connected in series with the AC power supply 2, and a resistor 4A is provided in parallel with the load 1.
And a control relay 5A for controlling energization of the resistor 4A
A microcomputer to which a load current value is transmitted from a current detecting means 7 for detecting the load current flowing through the load 1 by outputting a relay control signal for opening and closing the contacts of the control relay 5A and the load relay 3 Load 6E
When the load current flowing through the load relay 1 is very small, a current is forced to flow through the contacts of the load relay 1.

In the above structure, first, when the load 1 is driven, the microcomputer 6E moves the load relay 3
The relay control signal for closing the contact of is output and the contact of the load relay 3 is closed. Then, the steady-state current flowing through the load 1 is detected by the current detecting means 7, and the load current value is transmitted to the microcomputer 6E. If this load current value is less than or equal to the current value preset in the microcomputer 6E, when the microcomputer 6E outputs a relay control signal for closing the contact of the load relay 3 thereafter, the microcomputer 6E A relay control signal for closing the contact of the control relay 5A is output, and after the resistor 4A is connected to the load 1 in parallel, a relay control signal for closing the contact of the load relay 3 is output.

As described above, according to the relay protection apparatus of the sixth embodiment of the present invention, when the load current flowing through the load 1 is very small, the control relay 5A is used to flow the current to the contact of the load relay 3. By forcibly increasing the current, it is possible to prevent conduction failure due to oxidation of the contacts of the load relay 3, which occurs when the load current is very small.

[0049]

As is apparent from the above embodiments, according to the present invention, a resistor for limiting the inrush current is connected to limit the inrush current generated immediately after the contact of the load relay is closed. , Load relay contact transition phenomenon, welding, abnormal wear,
It is possible to provide a relay protection device that is effective in suppressing defects in the load relay contact such as an increase in contact resistance.

Further, since the value of the current flowing through the load is detected by the current detecting means, the inrush current generation time is longer than the normal time due to, for example, ambient temperature, variations in electronic parts, variations in power supply voltage, and the like. Even if the load relay contact is closed, it is possible to suppress the generation of inrush current flowing to the load, so contact failure such as transition phenomenon of the load relay contact, welding, abnormal wear, increase in contact resistance, etc. It is possible to provide a relay protection device that has the effect of suppressing the above.

Further, since the number of contact opening / closing times of the load relay stored in advance in the microcomputer is estimated and displayed based on the inrush current and the steady current value flowing in the load relay by the current detecting means, only the steady current, that is, the rated current is displayed. It is possible to provide a relay protection device that has an effect of being able to inform the reference of the number of contact lifes even in the case of an external load that is noted and easy to be constructed, or a load that has a large load current variation characteristic.

Further, by the inrush and steady-state current value by the current detecting means, the number of contact opening / closing lives of the load relay and the number of opening / closing of the load relay stored in the microcomputer in advance are stored in the nonvolatile memory. However, by judging that the service life is approaching based on the difference between the contact service life and the cumulative number of actual switching operations, and displaying it, it is possible to more accurately notify the contact service life time that greatly depends on the actual usage frequency. It is possible to provide a relay protection device having the above effect.

Further, when the load relay is slightly welded by detecting that the contact of the load relay is closed by the current detecting means, the contact is actually made in response to the load relay contact closing signal from the microcomputer. By utilizing the fact that the response time until it closes becomes slower than the initial response time, the time difference between the load relay contact closing signal from the microcomputer and the actual load relay contact closing is set in advance in the microcomputer. When the value exceeds the specified value, the microcomputer judges that the load relay contact has been slightly welded and displays a warning with the warning display means, so that the load relay contact may not be welded and the operation of the device may be incomplete. , It is possible to provide a relay protection device that is effective in preventing equipment from becoming unusable until maintenance such as parts replacement. That.

When the load relay contact is closed, and the load current detected by the current detecting means is relatively small, the control relay contact connected in parallel to the load is closed, and the resistor is closed. By forcibly flowing the current, the current flowing through the load relay contact is forcibly increased, so there is provided a relay protection device that is effective in preventing conduction failure due to oxidation of the contact that occurs due to the load current of the load relay being small. it can.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a relay protection device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a relay protection device according to a second embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a relay protection device according to a third embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a relay protection device according to a fourth embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a relay protection device according to a fifth embodiment of the present invention.

FIG. 6 is a block diagram showing an internal configuration of a microcomputer of the relay protection device.

FIG. 7 is a block diagram showing a configuration of a relay protection device according to a sixth embodiment of the present invention.

FIG. 8 is a block diagram showing a configuration of a conventional relay protection device.

[Explanation of symbols]

 1 load 2 AC power supply 3 load relay 4 resistance 4A resistance 5 control relay 5A control relay 6 micro computer 6A micro computer 6B micro computer 6C micro computer 6D micro computer 6E micro computer 7 current detection means 8 display means 8A display means 9 Nonvolatile memory 10 Warning display means

Claims (6)

[Claims] 1. An AC power supply for driving a load connected in series to the load, a load relay for supplying / disconnecting the AC power supply, and a contact immediately after the contact of the load relay is closed. A resistor that limits the inrush current, the control relay that closes the contact of the load relay in parallel with this resistance, and the contact closes after the load current becomes a steady current, and the load relay and control A relay protection device comprising a microcomputer for controlling the opening / closing operation of a relay and configured to connect the resistor to a load to limit an inrush current flowing to the load. 2. A current detecting means for detecting a load current value flowing through a load, and a microcomputer for controlling opening / closing operations of the load relay and the control relay based on the load current value detected by the current detecting means, The relay protection device according to claim 1, wherein the inrush current flowing through the load is limited by the load current value. 3. An AC power supply for driving a load connected in series to the load, a load relay for supplying / disconnecting the AC power supply, and a current detecting means for detecting a load current flowing through the load. While controlling the load relay based on the load current value from the current detection means, a microcomputer for estimating the contact opening / closing life of the load relay and a display means are provided for the load estimated by the microcomputer. A relay protection device configured to display the contact opening / closing life of a relay on the display means. 4. The contact opening / closing life of the load relay is calculated by accumulating the estimated life of the non-volatile memory for storing data from the microcomputer and the contact of the load relay stored in the non-volatile memory and the actual number of times of operation. 4. The relay protection device according to claim 3, further comprising a microcomputer for determining whether or not the display means is displayed. 5. An AC power supply for driving a load connected in series to the load, a load relay for supplying / disconnecting this AC power supply, and a current detection means for detecting a load current flowing through the load. According to the load current value of the current detection means, a microcomputer for controlling the load relay and a warning display means for displaying a warning from the microcomputer are provided, and the microcomputer detects the load relay contact by the current detection means. When the signal indicating that the load relay contact is closed and the time when the load relay contact is actually closed by detecting that it is closed exceeds a preset value, it is determined that there is slight welding, and the warning display means is used. Relay protection device configured to display a warning. 6. An AC power supply for driving a load connected in series to the load, a load relay for supplying / disconnecting the AC power supply, and a resistor provided in parallel with the load,
And a control relay, a current detection unit that detects a load current flowing in the load, and a microcomputer that controls the opening / closing operation of the control relay and the load relay based on the load current value from the current detection unit. And a relay protection device configured to close the control relay contact when the load current detected by the current detection means is relatively small in the microcomputer.