A relay contact performance test system and method based on infrared thermal imaging

Abstract

The application discloses a relay contact performance test system and method based on infrared thermal imaging, and relates to the field of relay contact performance test.The test system comprises an acquisition device, a test device and a time relay.The test device is connected with a tested relay and the time relay respectively, and is used for controlling the attraction and release of the contact of the tested relay through the time relay.The acquisition device is connected with the test device, and is used for acquiring the temperature of the contact of the tested relay, and further used for acquiring the attraction times and working time length of the contact of the tested relay.The application solves the problem that the current intermediate relay product performance test is only aimed at single parameters such as voltage, current and time, and the contact performance cannot be tested.

Description

Technical Field

[0001] This invention relates to the field of relay contact performance testing, and in particular to a relay contact performance testing system and method based on infrared thermal imaging. Background Technology

[0002] Currently, relay performance testing primarily involves individual measurements of resistance, voltage, and current. However, testing for the performance of contacts, which are prone to malfunctions, is lacking. Traditional performance testing methods include resistance measurement and voltage and current measurement. Resistance measurement uses a multimeter to measure the coil's ohms. Voltage and current measurement uses an adjustable regulated power supply and an ammeter connected in series in the test circuit. The regulated power supply voltage is gradually increased until the contact click is heard, and the voltage and current values ​​are recorded. Multiple measurements are taken, and the average value is calculated to obtain the pull-in voltage and pull-in current. Similarly, the pull-in voltage is gradually decreased until the contact click is heard, and the voltage and current values ​​are recorded to obtain the release voltage and current. Existing relay performance testing, which relies on measuring circuit resistance with a multimeter and using an adjustable regulated power supply and ammeter to test relay performance, has the following drawbacks:

[0003] 1) The test content is only for single parameters such as resistance, voltage and current, and there are no devices or methods for testing the performance of important component contacts.

[0004] 2) Current testing methods cannot reflect the actual performance of contacts under actual working conditions of continuous contact engagement and disengagement.

[0005] 3) Low testing efficiency, especially batch testing, requires personnel to manually record and summarize relevant test data.

[0006] 4) The testing process requires replacing and assembling the voltage regulator circuit, which poses a risk of electric shock. Summary of the Invention

[0007] The purpose of this invention is to provide a relay contact performance testing system and method based on infrared thermal imaging, which solves the problem that current intermediate relay product performance testing only targets single parameters such as voltage, current, and time, but cannot test contact performance.

[0008] To achieve the above objectives, the present invention provides the following solution:

[0009] A relay contact performance testing system based on infrared thermal imaging, the testing system comprising a data acquisition device, a testing device, and a time relay;

[0010] The testing device is connected to the relay under test and the time relay respectively, and is used to control the closing and releasing of the contacts of the relay under test through the time relay;

[0011] The acquisition device is connected to the testing device and is used to acquire the temperature of the contacts of the relay under test, as well as the number of times the contacts of the relay under test are engaged and the working time.

[0012] Optionally, the acquisition device includes an infrared thermal imager, a counter, and a timer.

[0013] Optionally, the acquisition device further includes an ammeter and voltmeter; the ammeter and voltmeter are used to detect the current value flowing through the contacts of the relay under test.

[0014] Optionally, the testing device includes a power module, a power switch, a sliding rheostat, a DC contactor, a shunt, and an intermediate relay; the time relay includes a first time relay and a second time relay.

[0015] The power module is connected to the sliding rheostat, the DC contactor and the intermediate relay respectively, and is used to convert 220V AC power into 24V DC power and to supply power to the sliding rheostat, the DC contactor and the intermediate relay;

[0016] The positive terminal of the power module is connected to one contact of the third group of contacts of the DC contactor; another contact of the third group of contacts of the DC contactor is connected to one end of the sliding rheostat; the other end of the sliding rheostat is connected to one contact of the relay under test and the output terminal of the coil of the intermediate relay; the other contact of the relay under test is connected to one end of the main circuit of the shunt; the other end of the main circuit of the shunt is connected to the negative terminal of the power module; the current detection circuit terminal of the shunt is connected to the current detection terminal of the ammeter / voltmeter; the current... The voltage detection terminal of the pressure gauge is connected to the positive terminal of the power supply module; the input terminal of the intermediate relay coil is connected to one contact of the second group of contacts of the DC contactor main contacts; the other contact of the second group of contacts of the DC contactor main contacts is connected to the positive terminal of the power supply module; the input terminal of the relay under test coil is connected to one contact of the second group of contacts of the DC contactor main contacts; the output terminal of the relay under test coil is connected to one contact of the normally open contact of the second time relay; the other contact of the normally open contact of the second time relay is connected to the negative terminal of the power supply module.

[0017] The positive terminal of the power module is connected to one contact of the first group of contacts of the DC contactor; the other contact of the first group of contacts of the DC contactor is connected to the input terminals of the coils of the first and second time relays respectively; the output terminal of the coil of the first time relay is connected to one contact of the energized delay disconnect contact of the second time relay; the other contact of the energized delay disconnect contact of the second time relay is connected to the negative terminal of the power module; the output terminal of the coil of the second time relay is connected to one contact of the normally open contact of the first time relay; the other contact of the normally open contact of the first time relay is connected to the negative terminal of the power module.

[0018] The positive terminal of the power module is connected to one end of the power switch; the other end of the power switch is connected to the input terminal of the coil of the DC contactor; and the output terminal of the coil of the DC contactor is connected to the negative terminal of the power module.

[0019] Optionally, the positive terminal of the power supply module is connected to the fourth terminal of the counter; the negative terminal of the power supply module is connected to the third terminal of the counter.

[0020] The first terminal of the counter is connected to one contact of the third set of normally open contacts of the intermediate relay; the second terminal of the counter is connected to the other contact of the third set of normally open contacts of the intermediate relay.

[0021] Optionally, the first terminal of the timer is connected to one contact of the second set of normally open contacts of the intermediate relay; the second terminal of the timer is connected to the other contact of the second set of normally open contacts of the intermediate relay.

[0022] Optionally, the resistance value of the sliding rheostat is in the range of 1.2Ω-10Ω.

[0023] Optionally, the time relay further includes a third time relay; the testing device further includes an AC switch;

[0024] One contact of the normally closed contact of the third time relay is connected to the output terminal of the coil of the DC contactor; the other contact of the normally closed contact of the third time relay is connected to the negative terminal of the power supply module.

[0025] The input terminal of the power module is connected to 220V AC power; the output terminal of the power module outputs 24V DC power.

[0026] The live wire of the 220V AC power supply is connected to one end of the AC power switch; the other end of the AC power switch is connected to the input terminal of the coil of the third time relay; the output terminal of the coil of the third time relay is connected to one contact of the first set of normally closed contacts of the intermediate relay; and the other contact of the first set of normally closed contacts of the intermediate relay is connected to the neutral wire of the 220V AC power supply.

[0027] Optionally, the test system further includes a test base; the relay under test is connected to the test device through the test base.

[0028] A method for testing the performance of relay contacts based on infrared thermal imaging, the method comprising:

[0029] The coil of the DC contactor is engaged;

[0030] Adjust the resistance of the sliding rheostat so that the current value detected by the ammeter and voltmeter reaches the set current value; the set current value is determined by the parameters of the relay under test.

[0031] The first and second time relays are adjusted so that the time interval between the closing and releasing of the contacts of the relay under test meets a set threshold; the set threshold is determined by the parameters of the relay under test.

[0032] The temperature of the contacts of the relay under test is collected using an infrared thermal imager within a set time period.

[0033] The maximum operating temperature of the contacts of the relay under test is determined based on the temperature.

[0034] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0035] This invention provides a relay contact performance testing system based on infrared thermal imaging. The testing system includes a data acquisition device, a testing device, and a time relay. The testing device is connected to both the relay under test and the time relay, and is used to control the closing and releasing of the contacts of the relay under test via the time relay. The data acquisition device is connected to the testing device and is used to acquire the temperature of the contacts of the relay under test, as well as the number of times the contacts of the relay under test close and the working time. This invention is based on the principle that relays are commonly used control circuit components in circuit control systems. When the contacts, a key component of relays, malfunction, the corresponding contact resistance changes significantly. According to Joule's law, heat also changes significantly under the influence of current. By using infrared thermal imaging technology to test the relay contact performance, this invention can comprehensively reflect the relay's performance, solving the problem that current intermediate relay performance testing only targets single parameters such as voltage, current, and time, and cannot test contact performance. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 A block diagram of a relay contact performance testing system based on infrared thermal imaging provided by the present invention;

[0038] Figure 2 The power module circuit diagram of the relay contact performance testing system based on infrared thermal imaging provided by the present invention;

[0039] Figure 3 The test circuit diagram of the relay contact performance testing system based on infrared thermal imaging provided by the present invention;

[0040] Figure 4 The circuit diagram of the timer connection in the relay contact performance testing system based on infrared thermal imaging provided by the present invention;

[0041] Figure 5 The flowchart of the relay contact performance testing method based on infrared thermal imaging provided by the present invention is shown. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] The purpose of this invention is to provide a relay contact performance testing system and method based on infrared thermal imaging, which solves the problem that current intermediate relay product performance testing only targets single parameters such as voltage, current, and time, but cannot test contact performance.

[0044] Terminology Explanation:

[0045] 1. Relay: A common control unit in electrical systems, mainly composed of contacts, wires, and coils.

[0046] 2. Contacts: The main component of a relay. Under electromagnetic action, the contacts constantly attract and release, which causes collisions and friction. Over time, this leads to problems such as wear, adhesion, and poor contact. In addition, installation problems such as poor soldering of the contacts are the most important cause of relay failure.

[0047] 3. Infrared thermal imaging technology: Similar to infrared temperature measurement in security checks, it uses an infrared thermal imager to collect the temperature of the target problem and determine whether the temperature is too high or the temperature rise is too large.

[0048] Intermediate relays, as commonly used control circuit components in circuit control systems, primarily function to transmit signals. In this process, they can use one control signal to control one or more other signals, completing start, stop, and linkage controls. Their main controlled object is the contactor, which in turn controls electrical components with greater load-bearing capacity. Their working principle is as follows: When the coil is energized, the moving iron core is attracted by electromagnetic force, causing the moving contact to move, opening and closing the normally open contact; when the coil is de-energized, the moving iron core is reset by the spring. When a certain input quantity (such as voltage, current, temperature, speed, pressure, etc.) reaches a predetermined value, it activates, changing the operating state of the control circuit to achieve the intended control or protection purpose.

[0049] The continuous operation of relays places high reliability demands on the contact quality. If a contact fails, it's difficult to detect externally, and such failures are not frequent or recurring; they may occur occasionally. Even occasional occurrences can alter the contact resistance, causing the voltage across the coil to drop below 85% of the rated voltage. This prevents the core from engaging, leading to circuit malfunction and potentially endangering personal safety. Currently, testing intermediate relays primarily involves measuring the resistance across the coil. However, because relays are protected by a safety casing, measuring the internal coil resistance requires removing the casing, which can damage the casing and compromise the relay's continued safety. Furthermore, this method is inefficient and requires power, posing a safety hazard.

[0050] In summary, existing detection methods are significantly lacking in accuracy, efficiency, and safety. There is an urgent need for an efficient, safe, and accurate method for detecting intermediate relays to ensure they are in normal working condition. Infrared thermal imaging technology can effectively solve these problems. When a relay is energized, according to Joule's law, Q = I²RT, meaning that current flowing through a resistor generates heat. Infrared thermal imagers can convert the heat energy captured by the lens into a temperature display through photoelectric conversion. By experimentally determining the normal temperature range of the intermediate relay under different load currents, the intermediate relay can be tested by measuring the temperature. However, currently, there is no relevant testing device. The testing device and method independently designed in this invention solve this problem.

[0051] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0052] Example 1

[0053] like Figure 1 As shown, the present invention provides a relay contact performance testing system based on infrared thermal imaging. The testing system includes a data acquisition device, a testing device, and a time relay.

[0054] The testing device is connected to both the relay under test and the time relay, and is used to control the closing and releasing of the contacts of the relay under test via the time relay. Specifically, the testing device includes a power module, a power switch, a sliding rheostat, a DC contactor, a shunt, and an intermediate relay; the time relay includes a first time relay and a second time relay. Further, the resistance value of the sliding rheostat is in the range of 1.2Ω-10Ω.

[0055] The data acquisition device, connected to the testing device, is used to acquire the temperature of the contacts of the relay under test, as well as the number of times the contacts of the relay under test engage and the operating time. Specifically, the data acquisition device includes an infrared thermal imager, a counter, and a timer. The data acquisition device also includes an ammeter and voltmeter; the ammeter and voltmeter are used to detect the current value flowing through the contacts of the relay under test.

[0056] The relay contact performance testing system based on infrared thermal imaging also includes a display screen and a controller; the acquisition device is connected to the controller and sends the temperature, the number of engagements, and the working time to the controller; the controller is connected to the display screen and sends the received temperature, the number of engagements, and the working time to the display screen; the display screen is used to display the received temperature, the number of engagements, and the working time.

[0057] like Figure 2 , Figure 3 and Figure 4 As shown, the circuit connection of the relay contact performance testing system based on infrared thermal imaging provided by the present invention is as follows:

[0058] The power module is connected to the sliding rheostat, the DC contactor, and the intermediate relay respectively, and is used to convert 220V AC power into 24V DC power and to supply power to the sliding rheostat, the DC contactor, and the intermediate relay.

[0059] The positive terminal of the power module is connected to one contact of the third group of contacts of the DC contactor; another contact of the third group of contacts of the DC contactor is connected to one end of the sliding rheostat; the other end of the sliding rheostat is connected to one contact of the relay under test and the output terminal of the coil of the intermediate relay; the other contact of the relay under test is connected to one end of the main circuit of the shunt; the other end of the main circuit of the shunt is connected to the negative terminal of the power module; the current detection circuit terminal of the shunt is connected to the current detection terminal of the ammeter / voltmeter; the current... The voltage detection terminal of the pressure gauge is connected to the positive terminal of the power supply module; the input terminal of the intermediate relay coil is connected to one contact of the second group of contacts of the DC contactor main contacts; the other contact of the second group of contacts of the DC contactor main contacts is connected to the positive terminal of the power supply module; the input terminal of the relay under test coil is connected to one contact of the second group of contacts of the DC contactor main contacts; the output terminal of the relay under test coil is connected to one contact of the normally open contact of the second time relay; the other contact of the normally open contact of the second time relay is connected to the negative terminal of the power supply module.

[0060] The positive terminal of the power module is connected to one contact of the first group of contacts of the DC contactor; the other contact of the first group of contacts of the DC contactor is connected to the input terminals of the coils of the first and second time relays respectively; the output terminal of the coil of the first time relay is connected to one contact of the energized delay disconnect contact of the second time relay; the other contact of the energized delay disconnect contact of the second time relay is connected to the negative terminal of the power module; the output terminal of the coil of the second time relay is connected to one contact of the normally open contact of the first time relay; the other contact of the normally open contact of the first time relay is connected to the negative terminal of the power module.

[0061] The positive terminal of the power module is connected to one end of the power switch; the other end of the power switch is connected to the input terminal of the coil of the DC contactor; and the output terminal of the coil of the DC contactor is connected to the negative terminal of the power module.

[0062] Specifically, the positive terminal of the power module is connected to the fourth terminal of the counter; the negative terminal of the power module is connected to the third terminal of the counter; the first terminal of the counter is connected to one contact of the third set of normally open contacts of the intermediate relay; and the second terminal of the counter is connected to the other contact of the third set of normally open contacts of the intermediate relay. The first terminal of the timer is connected to one contact of the second set of normally open contacts of the intermediate relay; and the second terminal of the timer is connected to the other contact of the second set of normally open contacts of the intermediate relay.

[0063] Furthermore, the time relay also includes a third time relay; the testing device also includes an AC switch; one contact of the normally closed contact of the third time relay is connected to the output terminal of the coil of the DC contactor; the other contact of the normally closed contact of the third time relay is connected to the negative terminal of the power supply module; the input terminal of the power supply module is connected to 220V AC power; the output terminal of the power supply module outputs 24V DC power; the live wire terminal of the 220V AC power is connected to one end of the AC switch; the other end of the AC switch is connected to the input terminal of the coil of the third time relay; the output terminal of the coil of the third time relay is connected to one contact of the first set of normally closed contacts of the intermediate relay; the other contact of the first set of normally closed contacts of the intermediate relay is connected to the neutral wire terminal of the 220V AC power.

[0064] In practical applications, the power module is specifically configured as follows: the L and N terminals of the AC power supply are connected to the L1 and N1 terminals respectively via an air switch QF120A, and a cooling fan is connected between the L1 and N1 terminals; the L1 terminal is also connected to one end of the AC switch SA1-1, and the other end of the AC switch SA1-1 is connected to pin 7 of the third time relay KT0, pin 2 of the third time relay KT0 is connected to pin 11 of the intermediate relay KA1, and pin 3 of the intermediate relay KA1 is connected to the N1 terminal; the L1 and N1 terminals of the AC power supply are connected to the L and N terminals of the 600W-24V switching power supply respectively; the output terminals of the 600W-24V switching power supply are P24 and N24 respectively; where P24 is the positive terminal and N24 is the negative terminal; the P24 terminal is connected to one end of the air switch QF225A, and the other end of the air switch QF225A is connected to IP24.

[0065] Specifically, the grounding wire PE is connected to the electrical box enclosure; the upper end (incoming end) of circuit breaker QF1 (20A) is connected to the incoming power supply L and N, and the lower end (outgoing end) is connected to leads L1 and N1 (where L and L1 are live wires, and N and N1 are neutral wires); the fan FS power supply wires are connected to L1 and N1 respectively; one end of the first group of contacts SA1-1 of rotary switch SA1 is connected to L1, and the other end is connected to terminal 7 of time relay KT0; terminal 2 of KT0 is connected to terminal 11 of KA1, and KA1... Terminal 3 is connected to N1; the internal terminals L and N of the switching power supply (600W-24VDC) are connected to L1 and N1 respectively, and the grounding terminal is connected to the electrical box body. The internal terminals V+ and V- have outgoing wire numbers P24 and N24 respectively (where P24 is the positive terminal of the 24V DC power supply and N24 is the negative terminal of the 24V DC power supply); the upper end (incoming terminal) of the circuit breaker QF2 (25A) is connected to P24, and the lower end (outgoing terminal) has a lead wire number of 1P24 (1P24 is the positive terminal of the 24V DC power supply).

[0066] In practical applications, IP24 is connected to one end of power switch SA1-2, and the other end of power switch SA1-2 is connected to the A1 terminal of DC contactor KM1; the A2 terminal of DC contactor KM1 is connected to the fifth pin of the third time relay KT0; and the eighth pin of the third time relay KT0 is connected to the N24 terminal.

[0067] Specifically, one end of the second group of contacts SA1-2 of rotary switch SA1 is connected to 1P24, and the other end is connected to terminal A1 of DC contactor KM1. Terminal A2 of DC contactor KM1 is connected to terminal ⑤ of time relay KT0, and terminal ⑧ of time relay KT0 is connected to N24.

[0068] IP24 is connected to one end of the auxiliary contact (NO) of DC contactor KM1, the other end of the auxiliary contact (NO) of DC contactor KM1 is connected to one end of indicator light HL1, and the other end of indicator light HL1 is connected to N24.

[0069] IP24 is connected to one end of the normally open contact of DC contactor KM1-1. The other end of the normally open contact of DC contactor KM1-1 is connected to pin 7 of the first time relay KT1. Pin 2 of the first time relay KT1 is connected to pin 5 of the second time relay KT2. Pin 8 of the second time relay KT2 is connected to terminal N24. Simultaneously, the other end of the normally open contact of DC contactor KM1-1 is connected to pin 7 of the second time relay KT2. Pin 2 of the second time relay KT2 is connected to pin 6 of the first time relay KT1. Pin 8 of the first time relay KT1 is connected to terminal N24.

[0070] Specifically, one end of the first group of main contacts KM1-1 of the DC contactor is connected to 1P24, and the other end is connected to the terminals ⑦ of time relays KT1 and KT2. Terminal ② of time relay KT1 is connected to terminal ⑤ of time relay KT2, terminal ② of time relay KT2 is connected to terminal ⑥ of time relay KT1, and terminals ⑧ of time relays KT1 and KT2 are connected to N24.

[0071] The IP24 terminal is connected to one end of the normally open contact of DC contactor KM1-2. The other end of the normally open contact of DC contactor KM1-2 is connected to pin 14 of the relay under test KA2. Pin 13 of the relay under test KA2 is connected to pin 1 of the second time relay. Pin 3 of the second time relay is connected to the N24 terminal. The other end of the normally open contact of DC contactor KM1-2 is connected to pin 14 of intermediate relay KA1. Pin 13 of intermediate relay KA1 is connected to pin 9 of the relay under test. Pin 5 of the relay under test is connected to one end of the main circuit of shunt FL (shunt 50A). The other end of the main circuit of shunt FL (shunt 50A) is connected to the N24 terminal. The current detection circuit terminal of shunt FL (shunt 50A) is connected to the current detection terminal of ammeter A. The voltage detection terminal of ammeter A is connected to the IP24 terminal.

[0072] Specifically, one end of the second group of contacts KM1-2 of the DC contactor is connected to 1P24, and the other end is connected to terminal 14 of intermediate relays KA1 and KA2. Terminal 13 of intermediate relay KA2 is connected to terminal ① of time relay KT2. Terminal ③ of time relay KT2 is connected to N24. Terminal 13 of intermediate relay KA1 is connected to terminal ⑨ of intermediate relay KA2. Terminal ⑤ of intermediate relay KA2 is connected to one end of the main circuit of shunt FL (shunt 50A). The other end of the main circuit of shunt FL (shunt 50A) is connected to N24. The current detection circuit terminal of shunt FL (shunt 50A) is connected to the current detection terminal of ammeter A. The voltage detection terminal of ammeter A is connected to 1P24.

[0073] The IP24 terminal is connected to one end of the normally open contact of the DC contactor KM1-3. The other end of the normally open contact of the DC contactor KM1-3 is connected to one pin of the sliding rheostat. The other pin of the sliding rheostat is connected to pin 13 of the intermediate relay KA1 and pin 9 of the relay under test KA2.

[0074] Specifically, one end of the third group of main contacts KM1-3 of the DC contactor is connected to 1P24, and the other end is connected to the sliding rheostat R (sliding rheostat). The other end of the sliding rheostat R (sliding rheostat) is connected to terminal ⑨ of the intermediate relay KA2.

[0075] The IP24 pin is connected to the four pins of counter C1, the three pins of counter C1 are connected to the N24 pin, the one pin of counter C1 is connected to the nine pins of the normally open contact of intermediate relay KA1-3, and the two pins of counter C1 are connected to the five pins of the normally open contact of intermediate relay KA1-3.

[0076] Specifically, terminal ④ of counter C1 is connected to 1P24, terminal ③ is connected to N24, terminal ① is connected to terminal ⑨ of intermediate relay KA1, and terminal 2 is connected to terminal ⑤ of intermediate relay KA1.

[0077] Pin 1 of timer T1 is connected to pin 6 of the normally open contact of intermediate relay KA1-2, and pin 2 of timer T1 is connected to pin 10 of the normally open contact of intermediate relay KA1-2. Timer T1 has its own battery. Pins 3 and 4 of timer T1 should not be connected to an external power supply, but they can be shorted to reset timer T1.

[0078] Specifically, terminal ① of T1 (timer) is connected to terminal ⑥ of intermediate relay KA1, terminal ② is connected to terminal ⑩ of intermediate relay KA1, and terminals ③ and ④ cannot be supplied with external power but can be shorted to reset the timer.

[0079] In this invention, the positive terminal of the power module is 1P24, the negative terminal of the power module is N24, the DC contactor is KM1, the third group of main contacts of the DC contactor is KM1-3, the relay under test is KA2, the intermediate relay is KA1, the second group of main contacts of the DC contactor is KM1-2, the first group of main contacts of the DC contactor is KM1-1, the second time relay is KT2, the first time relay is KT1, the third time relay is KT0, the power switch is SA1-2, the AC switch is SA1-1, the third group of normally open contacts of the intermediate relay is KA1-3, the second group of normally open contacts of the intermediate relay is KA1-2, and the first group of normally closed contacts of the intermediate relay is KA1-1.

[0080] In addition, the testing system also includes a test base; the relay under test is connected to the testing device through the test base. The test base is a relay base.

[0081] In practical applications, the testing device is installed in the electrical control cabinet. The device also includes a cooling fan, air switches QF1 and QF2, and displays for current and voltage, a counter, and a timer. The infrared thermal imager, model T640, is used for temperature acquisition and display. The switching power supply, model MEANWELL SE-600-24, converts 220V AC to 24V DC. The sliding rheostat is a custom-designed rheostat; given that the current passing through the contacts of intermediate relays is currently between 1A and 10A, the theoretical resistance of the rheostat is designed to be 1.2Ω-10Ω. By changing the resistance, the output current range of the rheostat is 2.4A-20A. The DC contactor KM1, model TeSys LC1D, is used for protection in the main circuit; it cuts off the 24V power supply when the contacts or coil burn out. There are three time relays, model AH3-3, DC24V. The third time relay is KT0, which is connected to a DC contactor for protection. By setting a time simulation, the DC contactor is automatically disconnected when the coil or contact burns out, and the relay stops engaging, thus protecting the 24V circuit. The first time relay KT1 and the second time relay KT2 are used for cyclic counting to ensure that the intermediate relays operate continuously according to the set time. The cooling fan is mainly used to cool the testing device and is directly connected to the air switch. The air switch QF1 (with leakage protection), model: DElixi 2P, connects to a 220V power supply to protect the AC circuit. The air switch QF2, model: CHNT NBE71P, connects to a 24V power supply to control the circuit's on / off state and protect the DC circuit from burnout. The intermediate relay KA1 outputs time and count values ​​by measuring its parameters. The intermediate relay under test KA2 allows for convenient and quick plugging and unplugging to improve efficiency. The current and voltage display shows the current and voltage of the tested circuit, with the voltage designed to be 24V and the current being the actual test current. The counter display shows the number of times the intermediate relay under test contacts close from the start until it burns out (power off). The timer display shows the time taken for the intermediate relay under test from the start until it burns out (power off). The counter model is JDM11-6H; the timer model is H7ET-BLM.

[0082] Furthermore, when different users use this infrared thermal imaging-based relay contact performance testing system to test the performance of relays, they can adjust the parameters of the testing system according to the testing needs and the parameters of the relay being tested. Through multiple experiments, the normal operating temperature threshold of different relays can be obtained. Based on this threshold, it can be determined whether the relay being tested is in normal operating condition.

[0083] The working principle of the relay contact performance testing system based on infrared thermal imaging provided by this invention is as follows:

[0084] The testing device allows for the testing of contact performance. It adjusts the current flowing through the contacts to match the designed operating conditions, and also adjusts the contact engagement and release times to maintain consistency with the design. Under the influence of current, the contacts continuously engage and release. After a period of operation, an infrared thermal imager captures the temperature distribution map of the contact surface and automatically interprets the data to determine contact performance. When relay contact performance malfunctions, the corresponding contact resistance changes significantly. According to Joule's law, heat also changes significantly under the influence of current. An infrared thermal imager can capture this temperature, and the contact performance can be determined based on the captured temperature readings. Furthermore, by setting a temperature warning value for the infrared thermal imager, automatic detection of performance compliance can be achieved.

[0085] The relay contact performance testing system based on infrared thermal imaging provided by this invention has the following advantages:

[0086] 1. The testing system can effectively test the performance of relay contacts.

[0087] 2. The testing system can change the contact engagement and release rates by modifying the parameter settings of the three time relays KT0, KT1, and KT2, in order to test the contact performance under different engagement and release rates. This can better simulate the actual working conditions of the relay contacts, and the test can better reflect the actual working conditions and contact performance.

[0088] 3. By externally changing the resistance value of the sliding rheostat, the contact performance under different current conditions can be tested.

[0089] 4. The parameters of each component in the test system meet the test requirements after actual manufacturing.

[0090] 5. The relay under test in the testing system can be directly plugged into and unplugged on the test base without changing the circuit and testing instruments, which is convenient to operate. It can also be set to automatically alarm when the temperature exceeds the limit via an infrared thermal imager or PC, realizing automatic judgment of test performance. No manual summary and statistics are required, which is simple and can realize the simultaneous testing of multiple samples in the same batch.

[0091] 6. The infrared thermal imager is a non-contact temperature measurement device, ensuring safety.

[0092] Example 2

[0093] In order to implement the system corresponding to Embodiment 1 above and achieve the corresponding functions and technical effects, a relay contact performance testing method based on infrared thermal imaging is provided below. The method includes:

[0094] Step S1: Engage the coil of the DC contactor.

[0095] Step S2: Adjust the resistance of the sliding rheostat so that the current value detected by the ammeter and voltmeter reaches the set current value; the set current value is determined by the parameters of the relay under test.

[0096] Step S3: Adjust the first time relay and the second time relay so that the time interval between the closing and releasing of the contacts of the relay under test meets the set threshold; the set threshold is determined by the parameters of the relay under test.

[0097] Step S4: Use an infrared thermal imager to collect the temperature of the contacts of the relay under test within a set time period.

[0098] Step S5: Determine the maximum operating temperature of the contacts of the relay under test based on the temperature.

[0099] like Figure 5 As shown, the actual testing process of the relay contact performance testing method based on infrared thermal imaging provided by this invention is as follows:

[0100] (1) Insert the relay to be tested into the test base and remove the outer casing.

[0101] (2) Turn on the infrared thermal imager, set the parameters according to the user manual, and aim at the relay under test to obtain a clear infrared image.

[0102] (3) Connect the test device to a 220V power supply, turn the main knob to the ON position, turn on QF1, power on the test device, and start the cooling fan.

[0103] (4) Turn on QF2 to test the power supply of the circuit.

[0104] (5) KM1 is turned "ON" to protect the circuit.

[0105] (6) Rotate the sliding rheostat handle until the current display reaches the test requirements (the test requirements are determined according to the test purpose and the parameters of the relay being tested. Different relays have different values. Generally, the current can be set to 1A, 3A, 5A, 7A, or 9A).

[0106] (7) According to the test purpose and the parameters of the relay under test, adjust the KT0, KT1 and KT2 knobs in sequence to ensure that the contact closing and releasing time of the relay meets the test requirements (the test requirements are determined according to the test purpose and the parameters of the relay under test, and are generally the actual closing and releasing time interval of the relay under test, such as 30ms or 20s, but this interval is achieved by adjusting the knob).

[0107] (8) After running for a period of time, the highest temperature point of the contact and the infrared spectrum are collected by an infrared thermal imager (the current state does not need to be repeated, that is, the test state of running for a period of time is maintained by keeping the set parameters of (7)). After powering on for a period of time and generating a temperature rise, the data is collected.

[0108] (9) Enterprises determine the temperature range of qualified products of different relays under different currents and switching times through a large number of tests. Based on the temperature range, they determine whether the contact temperature meets the requirements (different relays and test environment standards are different, and a large number of tests are required to determine the corresponding temperature range).

[0109] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0110] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A relay contact performance testing system based on infrared thermal imaging, characterized in that, The testing system includes a data acquisition device, a testing device, and a time relay; The testing device is connected to the relay under test and the time relay respectively, and is used to control the closing and releasing of the contacts of the relay under test through the time relay; The acquisition device is connected to the testing device and is used to acquire the temperature of the contacts of the relay under test, as well as the number of times the contacts of the relay under test are engaged and the working time. The testing device includes a power module, a power switch, a sliding rheostat, a DC contactor, a shunt, and an intermediate relay; the time relay includes a first time relay and a second time relay. The power module is connected to the sliding rheostat, the DC contactor and the intermediate relay respectively, and is used to convert 220V AC power into 24V DC power and to supply power to the sliding rheostat, the DC contactor and the intermediate relay; The positive terminal of the power module is connected to one contact of the third group of contacts of the DC contactor; another contact of the third group of contacts of the DC contactor is connected to one end of the sliding rheostat; the other end of the sliding rheostat is connected to one contact of the relay under test and the output terminal of the coil of the intermediate relay; the other contact of the relay under test is connected to one end of the main circuit of the shunt; the other end of the main circuit of the shunt is connected to the negative terminal of the power module; the current detection circuit terminal of the shunt is connected to the current detection terminal of the current and voltage meter; the current and voltage... The voltage detection terminal of the meter is connected to the positive terminal of the power supply module; the input terminal of the coil of the intermediate relay is connected to one contact of the second group of contacts of the DC contactor; the other contact of the second group of contacts of the DC contactor is connected to the positive terminal of the power supply module; the input terminal of the coil of the relay under test is connected to one contact of the second group of contacts of the DC contactor; the output terminal of the coil of the relay under test is connected to one contact of the normally open contact of the second time relay; the other contact of the normally open contact of the second time relay is connected to the negative terminal of the power supply module. The positive terminal of the power module is connected to one contact of the first group of contacts of the DC contactor; the other contact of the first group of contacts of the DC contactor is connected to the input terminals of the coils of the first and second time relays respectively; the output terminal of the coil of the first time relay is connected to one contact of the energized delay disconnect contact of the second time relay; the other contact of the energized delay disconnect contact of the second time relay is connected to the negative terminal of the power module; the output terminal of the coil of the second time relay is connected to one contact of the normally open contact of the first time relay; the other contact of the normally open contact of the first time relay is connected to the negative terminal of the power module. The positive terminal of the power module is connected to one end of the power switch; the other end of the power switch is connected to the input terminal of the coil of the DC contactor; and the output terminal of the coil of the DC contactor is connected to the negative terminal of the power module.

2. The relay contact performance testing system based on infrared thermal imaging according to claim 1, characterized in that, The acquisition device includes an infrared thermal imager, a counter, and a timer.

3. The relay contact performance testing system based on infrared thermal imaging according to claim 2, characterized in that, The acquisition device also includes an ammeter and voltmeter; the ammeter and voltmeter are used to detect the current value flowing through the contacts of the relay under test.

4. The relay contact performance testing system based on infrared thermal imaging according to claim 2, characterized in that, The positive terminal of the power supply module is connected to the fourth terminal of the counter; the negative terminal of the power supply module is connected to the third terminal of the counter. The first terminal of the counter is connected to one contact of the third set of normally open contacts of the intermediate relay; the second terminal of the counter is connected to the other contact of the third set of normally open contacts of the intermediate relay.

5. The relay contact performance testing system based on infrared thermal imaging according to claim 2, characterized in that, The first terminal of the timer is connected to one contact of the second set of normally open contacts of the intermediate relay; the second terminal of the timer is connected to the other contact of the second set of normally open contacts of the intermediate relay.

6. The relay contact performance testing system based on infrared thermal imaging according to claim 1, characterized in that, The resistance range of the sliding rheostat is 1.2Ω-10Ω.

7. The relay contact performance testing system based on infrared thermal imaging according to claim 1, characterized in that, The time relay also includes a third time relay; the testing device also includes an AC power switch; One contact of the normally closed contact of the third time relay is connected to the output terminal of the coil of the DC contactor; the other contact of the normally closed contact of the third time relay is connected to the negative terminal of the power supply module. The input terminal of the power module is connected to 220V AC power; the output terminal of the power module outputs 24V DC power. The live wire of the 220V AC power supply is connected to one end of the AC power switch; the other end of the AC power switch is connected to the input terminal of the coil of the third time relay; the output terminal of the coil of the third time relay is connected to one contact of the first set of normally closed contacts of the intermediate relay; and the other contact of the first set of normally closed contacts of the intermediate relay is connected to the neutral wire of the 220V AC power supply.

8. The relay contact performance testing system based on infrared thermal imaging according to claim 7, characterized in that, The testing system also includes a test base; the relay under test is connected to the testing device through the test base.

9. A method for testing the performance of relay contacts based on infrared thermal imaging, applied to the relay contact performance testing system based on infrared thermal imaging as described in any one of claims 1 to 8, characterized in that, The method includes: The coil of the DC contactor is engaged; Adjust the resistance of the sliding rheostat so that the current value detected by the ammeter and voltmeter reaches the set current value; the set current value is determined by the parameters of the relay under test. Adjust the first time relay and the second time relay so that the time interval between the closing and releasing of the contacts of the relay under test meets a set threshold; the set threshold is determined by the parameters of the relay under test. The temperature of the contacts of the relay under test is collected using an infrared thermal imager within a set time period. The maximum operating temperature of the contacts of the relay under test is determined based on the temperature.

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