Arc analysis methods and equipment for contactors

Abstract

This disclosure provides an arc analysis method and an arc analysis apparatus for a contactor. The arc analysis method includes: performing the engagement and disengagement of a moving contact and a stationary contact; performing a data acquisition operation, the data acquisition operation including acquiring voltage and current data of the main circuit of the contactor during a predetermined number of acquisitions of the engagement and disengagement of the moving and stationary contacts; performing an arc analysis operation, the arc analysis operation including: determining voltage and current data corresponding to the arc generated by each disengagement of the moving and stationary contacts from the acquired voltage and current data; determining individual arc characteristic values ​​of the contactor corresponding to each disengagement based on the voltage and current data corresponding to the arc generated by each disengagement of the moving and stationary contacts; and determining the arc characteristic value of the contactor based on the determined individual arc characteristic values ​​corresponding to each disengagement.

Description

Technical Field

[0001] This disclosure relates to a method and apparatus for analyzing the electric arc of a contactor. Background Technology

[0002] Contactors control the on / off state of the main circuit by the engagement and disengagement of their moving and stationary contacts. However, the separation of the moving and stationary contacts often generates an electric arc. The high temperature of the arc can burn the contacts and cause poor circuit contact over time. In certain scenarios, such as those sensitive to electric sparks, the arc can even cause explosions and personal injury. Therefore, arc analysis is beneficial for contactor design. Summary of the Invention

[0003] Therefore, the purpose of this disclosure is to provide an arc analysis method and an arc analysis device for contactors, which obtains the arc characteristic values ​​of the contactor by collecting voltage and current data of the main circuit of the contactor.

[0004] One aspect of this disclosure provides an arc analysis method for a contactor, the contactor including a moving contact and a stationary contact, wherein the closing of the moving and stationary contacts energizes the main circuit of the contactor, and the separation of the moving and stationary contacts de-energizes the main circuit, and the separation of the moving and stationary contacts generates an arc. The method includes: performing the closing and separation of the moving and stationary contacts; performing a data acquisition operation, the data acquisition operation including acquiring voltage data and current data of the main circuit of the contactor during a predetermined number of data acquisitions of the closing and separation of the moving and stationary contacts; performing an arc analysis operation, the arc analysis operation including: determining voltage data and current data corresponding to the arc generated by each separation of the moving and stationary contacts from the acquired voltage and current data; determining individual arc characteristic values ​​of the contactor corresponding to each separation based on the voltage data and current data corresponding to the arc generated by each separation of the moving and stationary contacts; and determining arc characteristic values ​​of the contactor based on the determined individual arc characteristic values ​​corresponding to each separation.

[0005] Optionally, the above-mentioned arc analysis operation further includes: determining that the contactor is abnormal if at least one of the determined arc characteristic values ​​of the contactor exceeds a corresponding threshold.

[0006] Optionally, the above-mentioned arc analysis method further includes: performing a data acquisition operation and an arc analysis operation whenever the total number of times the moving contact and the stationary contact engage and disengage reaches one of a plurality of predetermined total numbers.

[0007] Optionally, determining the voltage and current data corresponding to the arc generated by each separation of the moving and stationary contacts in the collected voltage and current data includes: determining the voltage and current data in the collected voltage and current data during the time interval from the moment the voltage changes from zero to non-zero to the moment the current changes from non-zero to zero as the voltage and current data corresponding to the arc generated by each separation of the moving and stationary contacts.

[0008] Optionally, the determination of the contactor's arc characteristic values ​​corresponding to each separation based on the voltage and current data of the arc generated by each separation of the moving and stationary contacts includes: for each time period between the voltage changing from zero to non-zero and the current changing from non-zero to zero: determining the duration of the time period as the total arc time of the contactor corresponding to this separation; integrating the product of the voltage data and the current data over the time period as the total arc energy of the contactor corresponding to this separation; and integrating the square of the current data over the time period as the total arc heat of the contactor corresponding to this separation.

[0009] Optionally, the above-mentioned determination of the contactor's arc characteristic value based on the determined arc characteristic values ​​corresponding to each separation includes: determining the average of the total arc time corresponding to each separation as the total arc time of the contactor; determining the average of the total arc energy corresponding to each separation as the total arc energy of the contactor; and determining the average of the total arc heat corresponding to each separation as the total arc heat of the contactor.

[0010] Another aspect of this disclosure provides an arc analysis device for a contactor, the contactor including a moving contact and a stationary contact, wherein the closing of the moving and stationary contacts energizes the main circuit of the contactor, and the separation of the moving and stationary contacts de-energizes the main circuit, and the separation of the moving and stationary contacts generates an arc. The arc analysis device includes: a driving unit for driving the closing and separation of the moving and stationary contacts; a data acquisition unit for performing a data acquisition operation, the data acquisition operation including acquiring voltage and current data of the main circuit of the contactor during a predetermined number of data acquisitions of the closing and separation of the moving and stationary contacts; and a processing unit for performing an arc analysis operation, the arc analysis operation including: determining voltage and current data corresponding to the arc generated by each separation of the moving and stationary contacts from the acquired voltage and current data; determining individual arc characteristic values ​​of the contactor corresponding to each separation based on the voltage and current data corresponding to the arc generated by each separation of the moving and stationary contacts; and determining an arc characteristic value of the contactor based on the determined individual arc characteristic values ​​corresponding to each separation.

[0011] Optionally, the arc analysis operation performed by the above processing unit further includes: determining that the contactor is abnormal if at least one of the determined arc characteristic values ​​of the contactor exceeds a corresponding threshold.

[0012] Optionally, the acquisition unit is further configured to perform an acquisition operation whenever the total number of times the moving contact and the stationary contact engage and disengage reaches one of a plurality of predetermined total numbers; and the processing unit is further configured to perform an arc analysis operation whenever the total number of times the moving contact and the stationary contact engage and disengage reaches one of a plurality of predetermined total numbers.

[0013] Optionally, the processing unit determines the voltage and current data in the collected voltage and current data for each time period between the moment when the voltage changes from zero to non-zero and the moment when the current changes from non-zero to zero as voltage and current data corresponding to the arc generated by each separation of the moving contact and the stationary contact.

[0014] Optionally, the processing unit performs the following operations for each time period between the moment when the voltage changes from zero to non-zero and the moment when the current changes from non-zero to zero: determining the duration of the time period as the total arc time of the contactor corresponding to this separation; determining the integral of the product of the voltage data and the current data over the time period as the total arc energy of the contactor corresponding to this separation; and determining the integral of the square of the current data over the time period as the total arc heat of the contactor corresponding to this separation.

[0015] Optionally, the processing unit determines the average of the total arc time corresponding to each separation as the total arc time of the contactor, the average of the total arc energy corresponding to each separation as the total arc energy of the contactor, and the average of the total arc heat corresponding to each separation as the arc thermal energy of the contactor.

[0016] The arc analysis method for contactors according to embodiments of the present disclosure and the arc analysis device for contactors according to embodiments of the present disclosure can be used at various stages of the contactor's lifespan to reflect the changing trend of the physical characteristics of the arc generated by the contactor over time. Attached Figure Description

[0017] These and / or other aspects, features, and advantages of this disclosure will become clearer and more readily understood from the following description of the disclosure in conjunction with the accompanying drawings, wherein:

[0018] Figure 1 A schematic diagram showing the arc motion process of the contactor is shown.

[0019] Figure 2 A flowchart is shown showing an arc analysis method for a contactor according to an embodiment of the present disclosure;

[0020] Figure 3 Examples of a portion of the acquired voltage and current waveforms corresponding to the engagement and disengagement of the primary moving and stationary contacts are shown;

[0021] Figure 4A This diagram shows the trend of the total arc energy of the contactor obtained by performing acquisition and arc analysis operations at various stages of the contactor's lifespan.

[0022] Figure 4B This graph shows the trend of the total arc heat of the contactor obtained by performing data acquisition and arc analysis operations at various stages of the contactor's lifespan.

[0023] Figure 5A A trend graph is shown showing the total arc energy of two contactors obtained by implementing the arc analysis method for contactors according to an embodiment of the present disclosure on two contactors with different designs;

[0024] Figure 5B The diagram shows a trend of the total arc heat of two contactors with different designs, obtained by implementing the arc analysis method for contactors according to embodiments of this disclosure; and

[0025] Figure 6 A block diagram of an arc analysis apparatus for a contactor according to an embodiment of the present disclosure is shown. Detailed Implementation

[0026] The present disclosure will now be described in detail with reference to exemplary embodiments thereof. However, the present disclosure is not limited to the embodiments described herein, which may be implemented in many different forms. The described embodiments are provided only to make the present disclosure thorough and complete, and to fully convey the concept of the present disclosure to those skilled in the art. Features of the various embodiments described may be combined with or substituted for each other, unless expressly excluded or should be excluded based on the context.

[0027] Figure 1 This is a schematic diagram of the arc motion process of the contactor.

[0028] A contactor consists of a moving contact and a stationary contact. It is used in an electrical system to control the connection and disconnection of the main circuit of the contactor by the engagement and disengagement of the moving and stationary contacts. When the moving and stationary contacts are engaged, the main circuit of the contactor is energized. When the moving and stationary contacts are disengaged, the main circuit of the contactor is de-energized.

[0029] The generation of an electric arc occurs when a gaseous medium, under certain conditions, undergoes intense ionization, producing numerous charged particles and transforming from an insulating to a conductive state. The generation of an electric arc in a contactor generally involves two processes: the generation of free electrons and the formation of the arc through collisional ionization. At the instant the moving and stationary contacts separate, the contact pressure and contact area between the contacts continuously decrease, causing the contact resistance to increase rapidly. This results in intense heating at the contact point, and the localized high temperature allows electrons to gain kinetic energy and potentially be emitted as free electrons. Alternatively, at the instant the moving and stationary contacts separate, due to the very small gap between the contacts, a very high electric field strength is formed under the influence of voltage. When the electric field strength exceeds 3 × 10⁻⁶, the electric field becomes extremely strong. 6 At a voltage of V / m, electrons on the cathode contact surface may be pulled out of the metal surface and become free electrons under the influence of a strong electric field. These free electrons accelerate under the influence of the electric field, constantly colliding with neutral gas particles (atoms or molecules), knocking out electrons from the outer orbits of neutral atoms to become new free electrons. This process intensifies and develops into an "electron avalanche." When a certain number of charged particles accumulate, the conductivity of the medium changes from that of an insulator to a conductor. Under the influence of voltage, current flows through the contact gap, forming an electric arc.

[0030] The high temperature of an electric arc can burn the contacts and cause poor circuit contact over time. Therefore, contactors often use arc-extinguishing devices such as arc-quenching grids to extinguish the arc. After an arc is generated, it will be elongated by the contraction force of the magnetic lines of force and enter the arc-quenching grid, dividing the long arc into multiple short arcs. When the alternating current crosses zero, all short arcs extinguish simultaneously. Due to the near-cathode effect, an initial dielectric strength of 150-250V immediately appears near the cathode of each short arc. As long as the sum of the initial dielectric strengths of all the short arcs in series is greater than the applied voltage between the contacts, the arc will not reignite.

[0031] refer to Figure 1 This diagram illustrates the four stages of arc movement in a contactor. The first stage is when the arc is between the moving and stationary contacts. The second stage is when the arc begins to leave the contacts; in this stage, the arc leaves the stationary contact, but a portion remains on the moving contact. The third stage is when the arc completely leaves the contacts; in this stage, the arc leaves both the stationary and moving contacts. The fourth stage is when the arc enters an arc-extinguishing device, such as an arc-extinguishing grid. In this stage, the arc is elongated and divided into multiple short arcs, and then gradually extinguishes.

[0032] Although the electric arc can be extinguished by the arc extinguishing device, both the moving and stationary contacts may be damaged due to the high temperature of the arc during each process from the generation to the extinguishing of the arc. Furthermore, with the repeated engagement and disengagement of the moving and stationary contacts, the contactor may malfunction due to severe contact damage, leading to circuit failure.

[0033] Based on this, this disclosure proposes an arc analysis method 200 for contactors. This analysis method can be used at various stages of the contactor's lifespan, making it easy to detect the changing trends of the contactor's arc-related characteristic values ​​and providing timely early warning.

[0034] Figure 2 This is a flowchart of an arc analysis method 200 for a contactor according to an embodiment of the present disclosure.

[0035] refer to Figure 2 The arc analysis method 200 for a contactor according to an embodiment of the present disclosure may include steps S210 to S230.

[0036] In step S210, the moving contact and the stationary contact are engaged and disengaged. This step can be performed on a test platform dedicated to contactors, in conjunction with an arc analysis device for contactors according to embodiments of this disclosure (which will be used in conjunction with the device). Figure 6 (As described in the text). The test platform is equipped with clamps that can hold the moving and stationary contacts separately. The arc analysis equipment includes a drive unit that can drive the moving and stationary contacts to engage and disengage, such as a device that drives the clamps to move so that the moving and stationary contacts engage and disengage.

[0037] In step S220, a data acquisition operation is performed, which includes acquiring voltage and current data of the main circuit of the contactor during a predetermined number of acquisitions (e.g., N times) of contacting and separating of the moving and stationary contacts. The arc analysis device includes acquisition units, such as voltage and current sensors, for acquiring voltage data U and current data I of the main circuit of the contactor during the predetermined number of acquisitions (e.g., N times) of contacting and separating of the moving and stationary contacts.

[0038] The voltage data U contains N voltage waveforms U corresponding to each engagement and disengagement of the moving and stationary contacts. i (i = 1 to N), the current data I contains N current waveforms I corresponding to each engagement and disengagement of the moving and stationary contacts. i (i = 1 to N). The voltage waveform U corresponding to the engagement and disengagement of one of the moving and stationary contacts. i and current waveform I i This can be further divided into voltage and current waveforms, respectively representing the separation period of the moving and stationary contacts, and other periods. Since the electric arc only occurs during the separation of the moving and stationary contacts, only the voltage waveform U... i (i = 1 to N) and current waveform I i The voltage waveform U in (i = 1 to N) corresponding to the arc generated during the separation of the moving and stationary contacts. i-arc (i = 1 to N) and current waveform Ii-arc (i = 1 to N) are the objects of analysis in the arc analysis method 200 according to an embodiment of the present disclosure.

[0039] In step S230, an arc analysis operation is performed. The processing unit included in the arc analysis equipment can be used to perform this operation. The arc analysis operation may include sub-steps S231 to S233.

[0040] In sub-step S231, the voltage and current data corresponding to the arcs generated by each separation of the moving and stationary contacts in the collected voltage and current data are determined. (See below for reference.) Figure 3 To describe this sub-step.

[0041] Figure 3 This is an example showing a portion of the voltage and current waveforms acquired corresponding to the engagement and disengagement of the primary moving and stationary contacts.

[0042] refer to Figure 3 The horizontal axis represents time, the left vertical axis represents voltage, and the right vertical axis represents current. The voltage waveform 301 and current waveform 302 shown in the figure are voltage waveforms U acquired in step S210 corresponding to the engagement and disengagement of the primary moving and stationary contacts. i and current waveform I i A portion thereof, which is included in the voltage waveform U of the arc generated during the separation of the moving contact and the stationary contact. i-arc and current waveform I i-arc In step S210, the moving and stationary contacts engage and disengage N times, resulting in N similar... Figure 3 The voltage and current waveforms of curves 301 and 302 are shown in the figure.

[0043] In sub-step S231, the voltage data U corresponding to the arc generated by each separation of the moving contact and the stationary contact in the collected voltage data U and current data I is determined. i-arc and current data I i-arc This includes: determining the voltage and current data in the collected voltage data U and current data I for each time interval between the moment the voltage changes from zero to non-zero and the moment the current changes from non-zero to zero as voltage data U corresponding to the arc generated by each separation of the moving and stationary contacts. i-arc and current data I i-arc .

[0044] like Figure 3 As shown, at time t1, the voltage changes from zero to non-zero, and at time t2, the current changes from non-zero to zero. Therefore, the voltage and current data between time t1 and time t2 are determined as the voltage data U of the arc generated by the separation of the moving and stationary contacts in this event. i-arcand current data I i-arc The reason for this determination is that when the moving and stationary contacts of the contactor are in the energized state, the main circuit of the contactor is energized, and the moving and stationary contacts together act as a conductor, with zero voltage and non-zero current. When the moving and stationary contacts begin to separate and generate an electric arc, the contact area between the moving and stationary contacts gradually decreases, the contact resistance gradually increases, and the voltage changes from zero to non-zero. The arc motion undergoes the following process... Figure 1 The current is extinguished after the four stages shown, and the current changes from non-zero to zero.

[0045] In this manner, for the voltage data U and current data I collected in step S220, i.e., N similar data... Figure 3 By analyzing the voltage and current waveforms of contacts 301 and 302, the voltage data U corresponding to the arc generated by each separation of the moving and stationary contacts can be determined. i-arc (i = 1 to N) and current data I i-arc (i = 1 to N).

[0046] In sub-step S232, based on the voltage data U corresponding to the arc generated by each separation of the moving contact and the stationary contact determined in sub-step S231... i-arc (i = 1 to N) and current data I i-arc (i = 1 to N) are used to determine the individual arc characteristic values ​​of the contactor corresponding to each separation. For each separation of the moving and stationary contacts, the calculable arc characteristic values ​​include, but are not limited to, the total arc time Δt experienced from arc generation to extinguishment. i-arc The total heat Q generated by the electric arc i-arc The total energy E generated by the electric arc and / or electric arc i-arc wait.

[0047] Still with Figure 3 For example, the voltage data U of the arc generated by the i-th separation of the moving contact and the stationary contact. i-arc and current data I i-arc The duration of the time interval between the moment when the voltage changes from zero to non-zero (t1) and the moment when the current changes from non-zero to zero (t2) is determined as the total arc separation time Δt. i-arc That is, Δt i-arc =t2-t1. Transform the voltage data U i-arc With current data I i-arc The integral of the product over that time period is determined as the total arc energy E of the contactor corresponding to this separation. i-arc ,Right now Current data I i-arc The integral of the square of the integral over that time period is determined as the total arc heat Q of the contactor corresponding to this separation. i-arc ,Right now

[0048] In sub-step S233, the arc characteristic value of the contactor is determined based on the individual arc characteristic values ​​corresponding to each separation determined in sub-step S232. For example, the average of the total arc time corresponding to each separation can be determined as the total arc time Δt of the contactor, i.e. The average of the total arc energy corresponding to each separation can be determined as the total arc energy E of the contactor, i.e. The average of the total arc heat corresponding to each separation can be determined as the total arc heat Q of the contactor, i.e. Of course, other methods can also be used to determine the arc characteristic values ​​of the contactor. For example, the median of the total arc time, the median of the total arc energy, and the median of the total arc heat corresponding to each separation can be determined as the total arc time Δt, the total arc energy E, and the total arc heat Q of the contactor, respectively. Alternatively, the weighted average of the total arc time, the weighted average of the total arc energy, and the weighted average of the total arc heat corresponding to each separation can be determined as the total arc time Δt, the total arc energy E, and the total arc heat Q of the contactor, respectively.

[0049] Therefore, through the above steps S210 to S230, by driving the contactor to engage and disengage the moving and stationary contacts, and by utilizing the voltage and current data of the contactor's main circuit collected during a predetermined number of acquisitions (e.g., N times) of engagement and disengagement of the moving and stationary contacts, corresponding to the voltage and current data of the arc generated by each separation of the moving and stationary contacts, the characteristic value of the contactor arc can be determined.

[0050] In some embodiments, step S230 may further include sub-step S234, that is, if at least one of the arc characteristic values ​​of the contactor determined by step S233 exceeds a corresponding threshold, it is determined that there is an abnormality in the contactor.

[0051] A threshold can be defined for each arc characteristic value based on empirical values ​​or relevant theoretical calculations. For example, a threshold T can be defined for the total arc time. Δt A threshold T is defined for the total energy of the electric arc. E A threshold T is defined for the total heat of the electric arc. Q When at least one of the total arc time Δt, total arc energy E, and total arc heat Q, determined through sub-step S233, exceeds its corresponding threshold T. Δt T E and T Q If this is the case, the contactor may be malfunctioning, meaning it may not meet the usage requirements. Continuing to use it may cause undesirable faults such as poor circuit contact or reduced contactor lifespan.

[0052] As the number of engagements and separations between the moving and stationary contacts increases, the characteristic value of the arc generated during separation also changes. Monitoring the arc characteristic value of the contactor at various life stages is very beneficial for predicting the trend of arc characteristic value changes and for early warning of contactor abnormalities. Multiple life stages for arc analysis can be predetermined. The life stage of the contactor is defined by the total number of engagements and separations between the moving and stationary contacts. Therefore, whenever the total number of engagements and separations of the moving and stationary contacts reaches one of several predetermined totals, the acquisition operation S220 and the arc analysis operation S230 can be executed to obtain the arc characteristic value of the contactor corresponding to each life stage, and thus obtain the trend of arc characteristic value changes. The following section combines... Figure 4A and Figure 4B Provide a detailed description.

[0053] Figure 4A The graph shows the trend of the total arc energy E of the contactor obtained by performing the acquisition operation S220 and the arc analysis operation S230 at various stages of the contactor's life.

[0054] refer to Figure 4A The four points 4011, 4012, 4013, and 4014 on curve 401 represent the total arc energy E values ​​obtained from arc analysis at four different stages of the contactor's lifespan. Point 4011 represents the initial stage of the contactor's lifespan, where the total arc energy E1 = 37.42 (VA) is calculated using the voltage and current data of the arc generated by the first 200 separations of the moving and stationary contacts. Point 4012 represents a period of time after the contactor's lifespan has ended, with a total of 79,000 engagements and disengagements of the moving and stationary contacts. The total arc energy E2 = 36.77 (VA) is calculated using the voltage and current data of the arc generated by the arc generated by the 79,001st to 79,200th separations of the moving and stationary contacts. Point 4013 indicates that the contactor's lifespan has continued for some time, with the total number of engagement and disengagement of the moving and stationary contacts reaching 100,000. Using the voltage and current data of the arc generated during the 100,001st to 100,200th separation of the moving and stationary contacts, the total arc energy of the contactor, E3, is calculated to be 35.7 (VA). Point 4014 indicates that the contactor's lifespan has continued for some time, with the total number of engagement and disengagement of the moving and stationary contacts reaching 170,000. Using the voltage and current data of the arc generated during the 170,001st to 170,200th separation of the moving and stationary contacts, the total arc energy of the contactor, E4, is calculated to be 39.56 (VA).

[0055] As can be seen from the figure, the total arc energy E changes relatively slowly in the early stage of the contactor's lifespan. For example, during the period when the total number of times the moving and stationary contacts engage and disengage is 1 to 100-200, the slope of curve 401 is relatively small. However, when the lifespan reaches a certain level, it changes rapidly. For example, after the total number of times reaches 100-200, the slope of curve 401 is relatively large.

[0056] Furthermore, assuming a threshold T for the total arc energy E E =38VA, then when the total number of times reaches 170200, the total energy of the arc E = 39.56VA > T. E In this case, it can be considered that the contactor is abnormal and does not meet the usage conditions, which serves as an early warning.

[0057] Figure 4B The graph shows the trend of the total arc heat Q of the contactor obtained by performing the acquisition operation S220 and the arc analysis operation S230 at various stages of the contactor's life.

[0058] refer to Figure 4B Similar to Figure 4A The four points 4021, 4022, 4023, and 4044 on wireless 402 represent the total arc energy Q values ​​obtained from arc analysis at four different life stages of the contactor. Point 4021 is the total arc energy Q1 of the contactor, calculated using the voltage and current data of the arc generated by the 1st to 200th separation of the moving and stationary contacts, equal to 219.9 (A). 2 Point 4022 is calculated using the voltage and current data of the arc generated by the separation of the moving and stationary contacts from the 79001st to the 79200th time, resulting in a total arc energy of Q2 = 230.51 (A). 2 Point 4023 is the total arc energy of the contactor, calculated using the voltage and current data of the arc generated during the 100001st to 100200th separation of the moving and stationary contacts, resulting in Q3 = 229.27 (A). 2 Point 4024 is the total arc energy of the contactor, calculated using the voltage and current data of the arc generated during the 170001st to 170200th separations of the moving and stationary contacts, resulting in Q4 = 264.79 (A). 2 s).

[0059] As can be seen from the figure, the total arc heat Q changes relatively slowly in the early stage of the contactor's lifespan. For example, during the period when the total number of times the moving and stationary contacts engage and disengage is 1 to 100-200, the slope of curve 402 is small. However, when the lifespan reaches a certain level, it changes rapidly. For example, after the total number of times reaches 100-200, the slope of curve 402 is large.

[0060] Furthermore, assuming the total arc heat Q threshold T Q =250A 2 If s, then when the total number of times reaches 170200, the total heat of the electric arc Q = 264.79A. 2 s>T Q In this case, it can be considered that the contactor is abnormal and does not meet the usage conditions, which also serves as an early warning.

[0061] The arc analysis method 200 for contactors according to embodiments of this disclosure can also be applied to contactor product design. By applying the arc analysis method 200 to two or more contactor samples with different designs under the same conditions and comparing the arc characteristic values ​​of the two or more contactors, the superiority or inferiority of the designs of the two or more contactor samples can be determined. The following is in conjunction with... Figure 5A and Figure 5B Detailed description.

[0062] Figure 5A The graph shows a trend of the total arc energy E of two contactors obtained by implementing the arc analysis method 200 for contactors according to an embodiment of the present disclosure on two contactors with different designs.

[0063] To ensure higher reliability of the analysis results, multiple contactor samples can be taken for each design. For example, reference... Figure 5A The solid lines 501 and 502 represent the trend of the total arc energy E for two contactor samples from different production batches, where the moving and stationary contacts are designed as rectangles, respectively. The solid lines 503 and 504 represent the trend of the total arc energy E for two contactor samples from different production batches, where the moving and stationary contacts are designed as squares, respectively. It can be clearly seen that at all stages of life, the total arc energy of the contactor with rectangular contacts (represented by solid lines 501 and 502) is generally less than that of the contactor with square contacts (represented by solid lines 503 and 504).

[0064] Figure 5B The diagram shows a trend of the total arc heat Q of two contactors obtained by implementing the arc analysis method 200 for contactors according to an embodiment of the present disclosure on two contactors with different designs.

[0065] refer to Figure 5BThe solid lines 505 and 506 represent trends in the total arc heat Q of two contactor samples from different production batches, where the moving and stationary contacts are designed as rectangles. The solid lines 507 and 508 represent trends in the total arc heat Q of two contactor samples from different production batches, where the moving and stationary contacts are designed as squares. It can be clearly seen that, at all stages of life, the total arc heat of the contactor with rectangular contacts (represented by solid lines 505 and 506) is generally less than that of the contactor with square contacts (represented by solid lines 507 and 508).

[0066] Combination Figure 5A and Figure 5B It can be argued that choosing rectangular moving and stationary contacts is more conducive to arc extinguishing, which provides a reference for contactor product design.

[0067] Figure 6 A block diagram of an arc analysis apparatus 600 for a contactor according to an embodiment of the present disclosure is shown.

[0068] refer to Figure 6 An arc analysis device 600 for a contactor includes a drive unit 610, a data acquisition unit 620, and a processing unit 630. The drive unit 610 drives the contactor's moving and stationary contacts to engage and disengage. The data acquisition unit 620 performs data acquisition operations, including acquiring voltage data U and current data I of the contactor's main circuit during a predetermined number of acquisitions (e.g., N times) of engagement and disengagement of the moving and stationary contacts. The data acquisition unit 620 may include a voltage sensor for acquiring voltage data U and a current sensor for acquiring current data I. The processing unit 630 performs arc analysis operations, including determining the voltage data U corresponding to the arc generated by each disengagement of the moving and stationary contacts from the acquired voltage data U and current data I. i-arc (i = 1 to N) and current data I i-arc (i = 1 to N); based on the voltage data U of the arc generated by each separation of the moving and stationary contacts. i-arc and current data I i-arc To determine the individual arc characteristic values ​​of the contactor corresponding to each separation, such as, but not limited to, the total arc time Δt. i-arc Total energy of electric arc E i-arc And the total heat of the electric arc Q i-arc ; and determine the contactor's arc characteristic value based on the determined arc characteristic values ​​corresponding to each separation, such as determining the total arc time of the contactor as Δt, the total arc energy of the contactor as E, and the total arc heat of the contactor as Q.

[0069] Processing unit 630 determines the voltage data U corresponding to the arc generated by each separation of the moving contact and the stationary contact from the collected voltage data U and current data I. i-arc (i = 1 to N) and current data I i-arc (i = 1 to N), specifically including: determining the voltage and current data in the collected voltage data U and current data I during the time interval from the moment t1 when the voltage changes from zero to non-zero to the moment t2 when the current changes from non-zero to zero as the voltage data U corresponding to the arc generated by each separation of the moving contact and the stationary contact. i-arc (i = 1 to N) and current data I i-arc (i = 1 to N).

[0070] The processing unit 630 is based on the voltage data U corresponding to the arc generated by each separation of the moving contact and the stationary contact. i-arc and current data I i-arc To determine the characteristic values ​​of each arc corresponding to each separation of the contactor, specifically including: the voltage data U of the arc generated for each separation of the moving and stationary contacts. i-arc and current data I i-arc That is, for each time interval between the moment t1 when the voltage changes from zero to non-zero and the moment t2 when the current changes from non-zero to zero, the voltage data U... i-arc and current data I i-arc The duration of this time period is defined as the total arc time Δt corresponding to this separation of the contactor. i-arc =t2-t1, the integral of the product of the voltage data and the current data over this time period is determined as the total arc energy of the contactor corresponding to this separation. And the integral of the square of the current data over that time period is used to determine the total arc heat of the contactor corresponding to this separation.

[0071] Processing unit 630 determines the arc characteristic value of the contactor based on the determined arc characteristic values ​​corresponding to each separation, specifically including: determining the average of the total arc time corresponding to each separation as the total arc time of the contactor. The average of the total arc energy corresponding to each separation is determined as the total arc energy of the contactor. The average of the total arc heat corresponding to each separation is determined as the arc thermal energy of the contactor.

[0072] The arc analysis operation performed by the processing unit 630 also includes determining that the contactor is malfunctioning if at least one of the determined arc characteristic values ​​of the contactor exceeds a corresponding threshold. For example, if at least one of the determined total arc time Δt, total arc energy E, and total arc heat Q exceeds a corresponding threshold T.Δt T E T Q If this occurs, the contactor may be malfunctioning, meaning it may no longer meet the usage requirements. Continuing to use it may cause undesirable malfunctions such as poor circuit contact or reduced contactor lifespan.

[0073] To avoid repetition, the arc analysis operation performed by the processing unit 630 will not be described in detail here. Please refer to the previous sections that have already been discussed. Figures 2 to 5B Related descriptions.

[0074] The acquisition unit 620 is also configured to perform an acquisition operation whenever the total number of times the moving contact and stationary contact engage and disengage reaches one of a plurality of predetermined total numbers. Simultaneously, the processing unit 630 is also configured to perform an arc analysis operation whenever the total number of times the moving contact and stationary contact engage and disengage reaches one of a plurality of predetermined total numbers. For example, as... Figure 4A and Figure 4B As shown, whenever the total number of times the moving and stationary contacts engage and disengage reaches one of a predetermined total number, such as 79,000, 100,000, or 170,000 times, the acquisition unit 620 and the processing unit 630 respectively perform acquisition and arc analysis operations to obtain arc characteristic values ​​for this lifespan stage. If an abnormality is identified in the contactor sample before it reaches its expected lifespan during testing, subsequent testing is unnecessary, saving development time for product development.

[0075] The arc analysis method 200 for contactors and the arc analysis device 600 for contactors according to embodiments of the present disclosure described above can be used at various stages of the contactor's lifespan to obtain the arc characteristic values ​​of the contactor at that stage. This facilitates observation of the changing trend of the arc characteristic values ​​of the contactor over time, and by determining whether the arc characteristic values ​​exceed a corresponding threshold, it can be determined whether the contactor has any abnormalities. Furthermore, by using the arc analysis method 200 for contactors with different designs under the same conditions, the advantages and disadvantages of these different designs can be determined by comparing the arc characteristic values ​​of these contactors under the same conditions, which greatly facilitates contactor product design.

[0076] The method flowcharts and device block diagrams disclosed herein are merely illustrative examples and are not intended to require or imply that connections or arrangements must be made in the manner shown in the flowcharts and block diagrams. As those skilled in the art will recognize, these devices and equipment can be connected and arranged in any manner that achieves the desired purpose.

[0077] Those skilled in the art should understand that the specific embodiments described above are merely examples and not limitations. Various modifications, combinations, partial combinations, and substitutions can be made to the embodiments of the present invention according to design requirements and other factors, as long as they are within the scope of the appended claims or their equivalents, and thus fall within the scope of the rights to be protected by this disclosure.

Claims

1. An arc analysis method for a contactor, the contactor comprising a moving contact and a stationary contact, wherein the engagement of the moving contact and the stationary contact energizes the main circuit of the contactor, the disengagement of the moving contact and the stationary contact de-energizes the main circuit, and the disengagement of the moving contact and the stationary contact generates an arc, the method comprising: Perform the engagement and disengagement of the moving contact and the stationary contact; When the total number of times the moving contact and the stationary contact engage and disengage reaches one of a plurality of predetermined total numbers defining different life stages of the contactor, an acquisition operation and an arc analysis operation are performed; The data acquisition operation includes acquiring voltage and current data of the main circuit of the contactor during a predetermined number of acquisitions when the moving contact and the stationary contact engage and disengage; The arc analysis operation includes: Determine the voltage and current data in the collected voltage and current data that correspond to the electric arc generated by each separation of the moving contact and the stationary contact; The characteristic values ​​of each arc of the contactor corresponding to each separation are determined based on the voltage and current data of the arc generated at each separation of the moving contact and the stationary contact; and The arc characteristic value of the contactor is determined based on the individual arc characteristic values ​​corresponding to each separation.

2. The arc analysis method as described in claim 1, wherein, The arc analysis operation also includes: If at least one of the determined arc characteristic values ​​of the contactor exceeds a corresponding threshold, the contactor is determined to be malfunctioning.

3. The arc analysis method as described in claim 1, wherein, The voltage and current data collected correspond to the arcs generated during each separation of the moving contact and the stationary contact, including: The voltage and current data collected from each time interval between the moment when the voltage changes from zero to non-zero and the moment when the current changes from non-zero to zero are determined as the voltage and current data corresponding to the arc generated by each separation of the moving contact and the stationary contact.

4. The arc analysis method as described in claim 3, wherein, The contactor's arc characteristic values ​​corresponding to each separation are determined based on voltage and current data of the arcs generated during each separation of the moving and stationary contacts, including: For each time interval between the moment when the voltage changes from zero to non-zero and the moment when the current changes from non-zero to zero: Voltage and current data: The duration of the time period is determined as the total arc time of the contactor corresponding to this separation; The integral of the product of the voltage data and the current data over the time period is determined as the total arc energy of the contactor corresponding to this separation; and The integral of the square of the current data over the time period is determined as the total arc heat of the contactor corresponding to this separation.

5. The arc analysis method as described in claim 4, wherein, The arc characteristic value of the contactor is determined based on the determined arc characteristic values ​​corresponding to each separation, including: The average of the total arc time corresponding to each separation is determined as the total arc time of the contactor; The average of the total arc energy corresponding to each separation is determined as the total arc energy of the contactor; and The average of the total arc heat corresponding to each separation is determined as the total arc heat of the contactor.

6. An arc analysis device for a contactor, the contactor including a moving contact and a stationary contact, wherein the engagement of the moving contact and the stationary contact energizes the main circuit of the contactor, the separation of the moving contact and the stationary contact de-energizes the main circuit, and the separation of the moving contact and the stationary contact generates an arc, the arc analysis device comprising: A driving unit is used to drive the moving contact and the stationary contact to engage and disengage; The acquisition unit is configured to perform an acquisition operation when the total number of engagements and disengagements of the moving contact and the stationary contact reaches one of a plurality of predetermined total numbers defining different life stages of the contactor. The acquisition operation includes acquiring voltage and current data of the main circuit of the contactor during the predetermined number of engagements and disengagements of the moving contact and the stationary contact. A processing unit is configured to perform an arc analysis operation, the arc analysis operation including: Determine the voltage and current data in the collected voltage and current data that correspond to the electric arc generated by each separation of the moving contact and the stationary contact; The characteristic values ​​of each arc of the contactor corresponding to each separation are determined based on the voltage and current data of the arc generated at each separation of the moving contact and the stationary contact; and The arc characteristic value of the contactor is determined based on the individual arc characteristic values ​​corresponding to each separation.

7. The arc analysis device as described in claim 6, wherein, The arc analysis operation also includes: If at least one of the determined arc characteristic values ​​of the contactor exceeds a corresponding threshold, the contactor is determined to be malfunctioning.

8. The arc analysis device as described in claim 7, wherein, The processing unit determines the voltage and current data in the collected voltage and current data for each time period between the moment when the voltage changes from zero to non-zero and the moment when the current changes from non-zero to zero as voltage and current data corresponding to the arc generated by each separation of the moving contact and the stationary contact.

9. The arc analysis device as described in claim 8, wherein, The processing unit performs the following operations on the voltage and current data for each time period between the moment when the voltage changes from zero to non-zero and the moment when the current changes from non-zero to zero: The duration of the time period is determined as the total arc time of the contactor corresponding to this separation; The integral of the product of the voltage data and the current data over the time period is determined as the total arc energy of the contactor corresponding to this separation; and The integral of the square of the current data over the time period is determined as the total arc heat of the contactor corresponding to this separation.

10. The arc analysis apparatus as described in claim 9, wherein, The processing unit determines the average of the total arc time corresponding to each separation as the total arc time of the contactor, the average of the total arc energy corresponding to each separation as the total arc energy of the contactor, and the average of the total arc heat corresponding to each separation as the arc heat energy of the contactor.

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