An electromagnet temperature rise test device

Abstract

The present invention discloses an electromagnet temperature rise test device, comprising a low resistance tester, a digital power supply, a main control circuit and a display screen; the main control circuit comprises a single chip microcomputer, a switching circuit and a switch circuit connected to the single chip microcomputer; the single chip microcomputer is electrically connected to the low resistance tester, the digital power supply and the display screen; the digital power supply, the switching circuit, the electromagnet to be tested, and the switch circuit are connected to form a first test loop; the low resistance tester, the switching circuit, and the electromagnet to be tested are connected to form a second test loop; the switching circuit is controlled by the single chip microcomputer, and the electromagnet to be tested is automatically switched to the first test loop or the second test loop; the switch circuit is controlled by the single chip microcomputer, and the first test loop is turned on or off. The present invention can accurately and efficiently complete the automated test of the electromagnet temperature rise test, save manpower, and avoid inaccurate data caused by human errors.

Description

Technical Field

[0001] The invention relates to the technical field of electromagnet testing equipment, and in particular to an electromagnet temperature rise testing device. Background Art

[0002] It is well known that electromagnets will generate heat during actual use after being powered on. Therefore, when purchasing or using electromagnets, the heating condition of the electromagnets during use is an extremely important parameter. Because if the coil temperature of the electromagnet is too high during use, the coil of the electromagnet will burn, causing the coil to short-circuit, and then burn the circuit board, and may even cause electrical fires and other serious catastrophic consequences. Therefore, the first thing that needs to be done for each type of electromagnet before leaving the factory is the "temperature rise" test.

[0003] In the prior art, the "temperature rise" test of the electromagnet adopts the traditional manual measurement method. It is necessary to first measure the "initial resistance" of the electromagnet, and then put it into the test. After a period of time, the test is "interrupted", the electromagnet is taken out to measure the resistance value of the electromagnet, and then the resistance value is recorded on paper, and then the electromagnet is put into the test again, and finally the temperature rise of the electromagnet coil is calculated according to the temperature rise calculation formula of the coil material.

[0004] Temperature rise formula: θ=(R2-R1) / R1*(235+t1)+t1-t2(K).

[0005] Where:

[0006] R2-winding resistance at the end of the test, Ω;

[0007] R1-winding resistance at the beginning of the test, Ω;

[0008] t1-winding temperature at the beginning of the test (generally room temperature), °C;

[0009] t2-cooling medium temperature at the end of the test (generally room temperature), °C;

[0010] 235 is a copper wire coil, and 225 is an aluminum wire coil.

[0011] The manual test of the temperature rise of the electromagnet has the following disadvantages:

[0012] 1. It is necessary to manually take out the electromagnet and measure the resistance at regular intervals, which is very troublesome and wastes labor, and the efficiency is also very low.

[0013] 2. It is necessary to manually calculate the temperature rise of the electromagnet through the temperature rise formula and record the data manually, which is inefficient and inevitably prone to human errors.

[0014] 3. In the on-off test, a "timed" interruption test is required, which destroys the continuity of the test, so the test result will be inaccurate.

[0015] 4. After the electromagnet is taken out, the temperature of the electromagnet will actually drop, and the test result will be low.

[0016] Therefore, the prior art needs to be improved. Summary of the invention

[0017] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to propose an electromagnet temperature rise test device, which aims to accurately and efficiently complete the automated test of the electromagnet temperature rise test, save manpower, and avoid inaccurate data caused by human errors.

[0018] To achieve the above object, the present invention adopts the following technical solutions:

[0019] An electromagnet temperature rise test device is used to perform a temperature rise test after being connected to the electromagnet to be tested, and includes:

[0020] Low resistance tester, digital power supply, main control circuit and display screen;

[0021] The main control circuit includes a single chip microcomputer, a switching circuit and a switch circuit connected to the single chip microcomputer;

[0022] The single chip microcomputer is electrically connected to a low resistance tester, a digital power supply and a display screen;

[0023] The digital power supply, the switching circuit, the electromagnet to be tested, and the switch circuit are connected to form a first test loop;

[0024] The low resistance tester, the switching circuit, and the electromagnet to be tested are connected to form a second test loop;

[0025] The switching circuit is controlled by a single chip microcomputer to automatically switch the electromagnet under test to the first test loop or the second test loop;

[0026] The switch circuit is controlled by a single chip microcomputer to turn on or off the first test loop.

[0027] Wherein, the single chip microcomputer model is STM32F103.

[0028] Wherein, the switching circuit includes an on-off transistor Q6, a double-pole relay coil, a double-pole relay contact mechanically connected to the double-pole relay coil, a first loop contact connected to the first test loop, and a second loop contact connected to the second test loop;

[0029] The collector of Q6 is connected to the single-chip microcomputer, the emitter is connected to the double-pole relay coil, and the base is grounded. The single-chip microcomputer controls the on and off of Q6 to control the power on and off of the double-pole relay coil. The double-pole relay contacts are connected to the electromagnet to be tested.

[0030] The double-pole relay coil connects the double-pole relay contact to the first loop contact or the second loop contact when it is powered on or off, thereby connecting the electromagnet to be tested to the first test loop or the second test loop.

[0031] Among them, an anti-backflow diode D12 is also connected between the emitter of Q6 and the double-pole relay coil.

[0032] Wherein, the switch circuit includes a MOS tube Q8, and voltage-dividing resistors R37 and R39;

[0033] The digital power supply is provided with a positive power supply electrode and a negative power supply electrode connected to the first test loop;

[0034] One end of R37 receives the control signal from the microcontroller, and the other end is connected to R39 and the gate of Q8. The other end of R39 is connected to the source of Q8 and grounded.

[0035] The drain of Q8 is connected to the positive pole of the digital power supply through the electromagnet under test, and the source of Q8 is connected to the negative pole of the digital power supply.

[0036] The main control circuit further includes an optocoupler U3 and a switch tube Q3, the input end of the optocoupler U3 is connected to the single chip microcomputer, the output end is connected to the collector of Q3, and the base of Q3 is connected to R37 of the switch circuit to control the on and off of Q8.

[0037] Wherein, the main control circuit further comprises a first serial port communication circuit, a second serial port communication circuit, a third serial port communication circuit and a fourth serial port communication circuit respectively connected to the single chip microcomputer;

[0038] The first serial port communication circuit includes a first communication chip connected to the single-chip microcomputer and a first serial port connected to the first communication chip, and the first serial port is connected to a digital power supply;

[0039] The second serial port communication circuit includes a second communication chip connected to the single-chip microcomputer and a second serial port connected to the second communication chip, and the second serial port is connected to the low resistance tester;

[0040] The third serial port communication circuit includes a third communication chip connected to the single chip microcomputer and a third serial port connected to the third communication chip, and the third serial port is connected to the display screen;

[0041] The fourth serial port communication circuit comprises a fourth communication chip connected to the single chip microcomputer and a fourth serial port connected to the fourth communication chip, and the fourth serial port is connected to the computer.

[0042] Among them, the models of the first communication chip, the second communication chip and the fourth communication chip are MAX3232, and the model of the third communication chip is MAX485.

[0043] Wherein, the main control circuit also includes a data storage circuit connected to the single-chip microcomputer.

[0044] Wherein, the main control circuit also includes a power supply circuit that provides a stable voltage.

[0045] The electromagnet temperature rise test device of the present invention is connected into a first test loop by a digital power supply, a switching circuit, an electromagnet to be tested, and a switching circuit, and a low resistance tester, a switching circuit, and an electromagnet to be tested are connected into a second test loop. The switching circuit automatically switches the electromagnet to be tested to be connected to the first test loop or the second test loop, and the switching circuit turns the first test loop on or off. In this way, when performing an electromagnet temperature rise test, the test device of the present invention can use the first test loop for on-off control, and after the first test loop is disconnected, it can automatically switch to the second test loop to measure the resistance, without manual switching or manual measurement, and the measured data can be automatically calculated by the single-chip microcomputer in the test device, thereby ensuring the accuracy of the result calculation. The test device of the present invention can automatically complete the electromagnet temperature rise test, save manpower, and improve the test efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0047] Figure 1 This is a schematic diagram of the circuit principle of the first embodiment of the electromagnet temperature rise testing device of the present invention.

[0048] Figure 2 It is a circuit connection schematic diagram of the single chip microcomputer of the present invention.

[0049] Figure 3 It is a circuit connection diagram of the first test loop and the second test loop of the present invention.

[0050] Figure 4 Schematic diagram of the circuit connection of the optocoupler of the present invention.

[0051] Figure 5 This is a schematic diagram of the connection of the first serial communication circuit of the present invention.

[0052] Figure 6 This is a schematic diagram of the connection of the second serial communication circuit of the present invention.

[0053] Figure 7 This is a schematic diagram of the connection of the third serial communication circuit of the present invention.

[0054] Figure 8 This is a schematic diagram of the fourth serial communication circuit connection of the present invention.

[0055] Fig. 9 This is a connection diagram of the data storage circuit of the present invention.

[0056] Fig.10 This is a schematic diagram of the connection of the first power supply circuit of the present invention.

[0057] Fig.11 This is a schematic diagram of the connection of the second power supply circuit of the present invention.

[0058] Description of reference numerals:

[0059] 100-test device, 10-low resistance tester, 20-digital power supply, 30-main control circuit, 31-single chip microcomputer, 32-switching circuit, 321-double-pole relay coil, 322-double-pole relay contact, 323-first loop contact, 324-second loop contact, 33-switching circuit, 34-first serial port communication circuit, 341-first communication chip, 342-first serial port, 35-second serial port communication circuit, 351-second communication chip, 352-second serial port, 36-third serial port communication circuit, 361-third communication chip, 362-third serial port, 37-fourth serial port communication circuit, 371-fourth communication chip, 372-fourth serial port, 38-data storage circuit, 39-power supply circuit, 39a-first power supply circuit, 39b-second power supply circuit, 40-display screen, 50-computer, 200-tested electromagnet. DETAILED DESCRIPTION

[0060] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0061] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0062] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0063] In addition, in the present invention, the descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0064] Please refer to Figure 1 The present invention provides an electromagnet temperature rise test device 100, which is used to connect to the electromagnet 200 to perform a temperature rise test on the electromagnet. The test device 100 includes:

[0065] Low resistance tester 10, digital power supply 20, main control circuit 30 and display screen 40. Low resistance tester 10 is used to measure the actual resistance of the electromagnet 200 to be tested. Preferably, the model of the low resistance tester 10 of the present invention is TH2512A.

[0066] The digital power supply 20 provides power for the electromagnet under test. At the same time, when the electromagnet under test is subjected to a continuous temperature rise test, the electromagnet under test does not need to be powered off and paused during the test to measure the resistance of the electromagnet under test. The digital power supply 20 provides the voltage value and the actual current value at a certain moment to the single-chip microcomputer through the serial port, and then the single-chip microcomputer can calculate the resistance value of the electromagnet through the "Ohm's law". Then the single-chip microcomputer can also calculate the temperature rise value of the electromagnet coil through the "temperature rise formula". There is no need to interrupt the power supply in order to obtain the resistance value at a certain moment in the middle as in the prior art. That is, the setting of the digital power supply 20 of the present invention makes it no longer necessary to interrupt the test multiple times in order to test the resistance of the electromagnet during the continuous power-on temperature rise test in the present invention, thereby avoiding the influence of the experimental results due to the interruption of the power supply and ensuring the accuracy of the test.

[0067] The display screen 40 of the present invention may be a touch display screen. It is understandable that if the display screen 40 of the present invention is a common display screen, the testing device 100 of the present invention also needs to be configured with input devices such as a keyboard, a mouse, and the like.

[0068] The display screen 40 is used to display various parameters such as voltage, current and temperature rise test results.

[0069] The main control circuit 30 of the present invention includes a single chip microcomputer 31 , a switching circuit 32 and a switch circuit 33 connected to the single chip microcomputer 31 .

[0070] The single chip microcomputer 31 is electrically connected to the low resistance tester 10 , the digital power supply 20 and the display screen 40 for data transmission.

[0071] like Figure 1 As shown, the digital power supply 20, the switching circuit 32, the electromagnet 200 to be tested, and the switch circuit 33 of the present invention are connected to form a first test loop. The low resistance tester 10, the switching circuit 32, and the electromagnet 200 to be tested are connected to form a second test loop.

[0072] That is, when the electromagnet 200 under test is connected to the first test loop or the second test loop, different test requirements can be met. Since the first test loop has a digital power supply 20, it can supply power to the electromagnet 200 under test, and the output voltage and current of the digital power supply 20 can be obtained at any time point during the power-on process to obtain the resistance value of the electromagnet 200 under test. The resistance value of the electromagnet 200 under test can be measured without power failure, which can meet the requirements of continuous power-on test. Since the second test loop is provided with a low resistance tester 10, the resistance of the electromagnet 200 under test can be measured using the second test loop immediately after the electromagnet 200 under test is powered off during the on-off test.

[0073] The switching circuit 32 is controlled by the single chip microcomputer 31 to automatically switch the electromagnet 200 under test to the first test loop or the second test loop; the switch circuit 33 is controlled by the single chip microcomputer 31 to turn on or off the first test loop.

[0074] The switching of the first test loop or the second test loop of the present invention is automatically realized by the single chip microcomputer 31 controlling the switching circuit 32, and the switch circuit 33 realizes the on-off control of the first test loop to meet the requirements of the on-off test.

[0075] The single chip microcomputer 31 of the test device 100 of the present invention performs the following functions:

[0076] 1. Read the resistance signal of the electromagnet 200 under test sent by the low resistance tester 10.

[0077] 2. Read the voltage and current values ​​sent by the digital power supply 20.

[0078] 3. Control the opening and closing of the power output of the digital power supply 20, as well as the setting of the voltage and current of the digital power supply 20.

[0079] 4. When the resistance of the electromagnet 200 under test needs to be measured in a power-off state, the control switches to the second test loop, and when the electromagnet 200 under test needs to be energized, the control switches to the first test loop to energize the electromagnet 200 under test.

[0080] 5. Test data can be sent to the host computer program through the serial port, and the data and commands sent by the host computer program can be received and processed.

[0081] 6. Send the test data and calculation results to the display screen 40 for display. When the display screen is a touch screen, receive the user input data and commands transmitted by the touch screen.

[0082] 7. Store the parameters set this time so that the previous setting data can be restored when the machine is turned on next time.

[0083] The electromagnet temperature rise test device 100 of the present invention can automatically complete the temperature rise test of the electromagnet, save manpower, improve the test efficiency, and does not require manual switching or manual measurement. The measured data will be automatically calculated by the single chip microcomputer 31 in the test device 100, ensuring the accuracy of the result calculation.

[0084] Preferably, if Figure 2 As shown, the model of the single chip computer 31 of the present invention is STM32F103.

[0085] Since the above control is relatively complex and the number of serial ports required is relatively large, the embodiment of the present invention selects to use a 32-bit advanced single-chip microcomputer: STM32F103 as the main processor. It has five serial ports itself, which can meet the needs of multiple serial ports. The peripheral circuit of STM32F103 includes a standard 8M crystal oscillator and a standard JTAG program burning interface, etc., as the minimum system circuit of the single-chip microcomputer.

[0086] Specifically, Figure 3 As shown, the switching circuit 32 of the present invention includes an on-off transistor Q6, a double-pole relay coil 321, a double-pole relay contact 322 mechanically connected to the double-pole relay coil 321, a first loop contact 323 connected to the first test loop, and a second loop contact 324 connected to the second test loop.

[0087] The collector C of Q6 is connected to the single-chip microcomputer 31, the emitter E is connected to the double-pole relay coil, the base B is grounded, the single-chip microcomputer 31 controls the on and off of Q6 to control the power on and off of the double-pole relay coil 321, and the double-pole relay contact 322 is connected to the electromagnet 200 under test.

[0088] When the double-pole relay coil 321 is energized or de-energized, the double-pole relay contact 322 is connected to the first loop contact 323 or the second loop contact 324 , thereby connecting the electromagnet 200 under test to the first test loop or the second test loop.

[0089] In the embodiment of the present invention, the collector C of Q6 is connected to the Pb8 pin of the single-chip microcomputer 31 through the current limiting resistor R6. The single-chip microcomputer 31 controls the output level of Pb8 to control the on and off of Q6. When Q6 is turned on, the double-pole relay coil 321 is energized, and then the double-pole relay contact 322 is actuated. When Q6 is disconnected, the double-pole relay coil 321 is de-energized, and then the double-pole relay contact 322 is actuated. It can be understood that, as a mode, when the double-pole relay coil 321 of the present invention is energized, the double-pole relay contact 322 is connected to the first loop contact 323 and the electromagnet 200 to be tested is connected to the first test loop; when the double-pole relay coil 321 is de-energized, the double-pole relay contact 322 is connected to the second loop contact 324 and the electromagnet 200 to be tested is connected to the second test loop.

[0090] Furthermore, an anti-backflow diode D12 is connected between the emitter E of Q6 of the present invention and the double-pole relay coil 321. The anti-backflow diode D12 prevents the double-pole relay coil 321 from flowing into Q6 in reverse and damaging Q6.

[0091] like Figure 3 As shown, the switch circuit 33 of the present invention includes a MOS tube Q8, and voltage-dividing resistors R37 and R39.

[0092] The digital power supply 20 is provided with a positive power supply and a negative power supply connected to the first test loop.

[0093] One end of R37 receives the control signal from the single chip computer 31, and the other end is connected to R39 and the gate of Q8. The other end of R39 is connected to the source of Q8 and grounded. The drain of Q8 is connected to the positive power supply of the digital power supply 20 through the electromagnet 200 under test, and the source of Q8 is connected to the negative power supply of the digital power supply 20.

[0094] The present invention uses the MOS tube Q8 as a switch tube, which can adapt to high-frequency switch on-off tests, such as powering on for one millisecond and then off for one millisecond. Relay contacts cannot achieve this function, but MOS tubes can meet the requirements.

[0095] As a specific implementation:

[0096] When the double-pole relay coil 321 is energized, the double-pole relay contact 322 is driven to actuate and connect to the first loop contact 323, and the electromagnet 200 under test is connected to the first test loop. At this time, the current flows out from the positive pole of the digital power supply 20, flows into the electromagnet 200 under test, and then flows into the D pole of Q8. At this time, the G pole of Q8 is turned on after receiving the turn-on signal sent by the single-chip microcomputer from P2x, and the current flows out from the S pole of Q8 and enters the negative pole of the digital power supply 20 to complete the current flow of the entire first test loop;

[0097] When the double-pole relay coil 321 loses power, the double-pole relay contact 322 is driven to actuate and connect with the second loop contact 324, and the electromagnet 200 under test is connected to the second test loop. At this time, the current flows out from the positive pole of the low resistance tester 10, flows into the electromagnet 200 under test, and then flows back to the negative pole of the low resistance tester 10 to complete the current flow of the entire second test loop.

[0098] Preferably, if Figure 4 As shown, the main control circuit 30 of the present invention also includes an optical coupler U3 and a switch tube Q3, the input end of the optical coupler U3 is connected to the single-chip computer 31, the output end is connected to the collector C of Q3, and the base B of Q3 is connected to R37 of the switch circuit 33 to control the conduction and shutdown of Q8. In the figure, the emitter E of Q3 is connected to the power supply, and Q1 and Q5 are standby switch tubes, which can control the on and off of three drive signals at the same time. The optical coupler U3 adopts TLP521-4, which plays the role of isolating the single-chip computer 31 from the MOS tube Q8 and the electromagnet 200 to be tested, so as to protect the single-chip computer 31.

[0099] Please continue to refer to Figure 1 The main control circuit 30 of the present invention further includes a first serial communication circuit 34, a second serial communication circuit 35, a third serial communication circuit 36 ​​and a fourth serial communication circuit 37 connected to the single-chip computer 31.

[0100] Specifically, Figure 5 As shown, the first serial port communication circuit 34 includes a first communication chip 341 connected to the single chip computer 31 and a first serial port 342 connected to the first communication chip 341 . The first serial port 342 is connected to the digital power supply 20 .

[0101] The first communication chip 341 adopts a MAX3232 chip. Since the control interface of the digital power supply 20 is an RS232 communication interface, the MAX3232 chip is required to convert the RS232 signal into a TTL signal of the single-chip microcomputer STM32.

[0102] like Figure 6 As shown, the second serial port communication circuit 35 includes a second communication chip 351 connected to the single chip computer 31 and a second serial port 352 connected to the second communication chip 351 , and the second serial port 352 is connected to the low resistance tester 10 .

[0103] The second communication chip 351 also uses a MAX3232 chip. Since the low resistance tester 10 of the embodiment of the present invention uses a tester of model TH2512A, which also uses RS232 communication, a MAX3232 chip is also needed to convert the RS232 signal of the low resistance tester into a TTL signal recognized by the single chip microcomputer STM32.

[0104] like Figure 7As shown, the third serial port communication circuit 36 ​​of the present invention includes a third communication chip 361 connected to the single chip computer 31 and a third serial port 362 connected to the third communication chip 361 , and the third serial port 362 is connected to the display screen 40 .

[0105] The embodiment of the present invention uses a RS485 interface touch screen, so the third communication chip 361 uses a MAX485 chip to convert the level.

[0106] The data obtained by testing the single chip microcomputer 31 of the present invention, such as the number of actions, current resistance, and current temperature rise, etc., will be displayed on the touch screen.

[0107] like Figure 8 As shown, the fourth serial port communication circuit 37 of the present invention comprises a fourth communication chip 371 connected to the single chip computer 31 and a fourth serial port 372 connected to the fourth communication chip 371, and the fourth serial port 372 is connected to the computer 50. The fourth communication chip 371 also adopts a MAX3232 chip.

[0108] The function of the test device 100 of the present invention to connect to the computer 50 is that the computer 50 is responsible for opening the "temperature rise test program" and then receiving various data sent from the serial port of the single-chip computer 31 through the computer serial port. Every time a data is received, the computer program will display it on the computer screen and store the test data in the corresponding file according to the file name set by the user. At any time, if the operator needs the test data, he only needs to open this file, and no manual timing intervention is required. Therefore, during the entire test process, the operator's intervention is almost unnecessary. The work efficiency is improved and the labor force is liberated.

[0109] Furthermore, if Fig. 9 As shown, the main control circuit 30 of the test device 100 of the present invention further includes a data storage circuit 38 connected to the single chip computer 31. In the embodiment of the present invention, the data storage circuit 38 uses a chip 24C02.

[0110] This embodiment uses 24C02 chip to store some parameters and data in the setting process of the single-chip microcomputer 31 to prevent the loss of the setting parameters, and can quickly call the previously set parameters after starting up, avoiding repeated operations and improving efficiency.

[0111] Preferably, the main control circuit 30 of the test device 100 of the present invention further includes a power supply circuit 39 for providing a stable voltage. Fig.10 and Fig.11 As described above, the power supply circuit 39 includes a first power supply circuit 39a and a second power supply circuit 39b.

[0112] The first power supply circuit 39a provides positive and negative 16V and positive and negative 12V regulated power supplies for various interfaces after rectification and filtering.

[0113] After the voltage reduction process, the second power supply circuit 39b finally provides a 3.3V regulated power supply to power the single chip microcomputer 31 and other chips.

[0114] The electromagnet temperature rise test device 100 proposed in the embodiment of the present invention connects the digital power supply 20, the switching circuit 32, the electromagnet 200 to be tested, and the switch circuit 33 into a first test loop, connects the low resistance tester 10, the switching circuit 32, and the electromagnet 200 to be tested into a second test loop, and the switching circuit 32 automatically switches the electromagnet 200 to be tested to the first test loop or the second test loop, and the switch circuit 33 turns the first test loop on or off, so that when performing the electromagnet temperature rise test, the test device 100 of the present invention can use the first test loop for on-off control, and after the first test loop is disconnected, it can automatically switch to the second test loop to measure the resistance, without manual switching, without manual measurement, and the measured data will be automatically calculated by the single-chip microcomputer 31 in the test device 100, ensuring the accuracy of the result calculation. The test device 100 of the present invention can automatically complete the temperature rise test of the electromagnet, save manpower, and improve the test efficiency.

[0115] The above description is only an example to clearly illustrate the present invention, and does not limit the patent scope of the present invention. It is impossible to list all the implementation methods here. All equivalent structural changes made by using the contents of the technical solution of the present invention under the concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. An electromagnet temperature rise test device, used for connecting to the electromagnet to be tested and then performing a temperature rise test, characterized in that: include: Low resistance tester, digital power supply, main control circuit and display screen; The main control circuit includes a single chip microcomputer, a switching circuit and a switch circuit connected to the single chip microcomputer; The single chip microcomputer is electrically connected to a low resistance tester, a digital power supply and a display screen; The digital power supply, the switching circuit, the electromagnet to be tested, and the switch circuit are connected to form a first test loop; The low resistance tester, the switching circuit, and the electromagnet to be tested are connected to form a second test loop; The switching circuit is controlled by a single chip microcomputer to automatically switch the electromagnet under test to the first test loop or the second test loop; The switch circuit is controlled by the single chip microcomputer to turn on or off the first test loop; The switch circuit includes a MOS tube Q8, and voltage-dividing resistors R37 and R39; The digital power supply is provided with a positive power supply electrode and a negative power supply electrode connected to the first test loop; One end of R37 receives the control signal from the microcontroller, and the other end is connected to R39 and the gate of Q8. The other end of R39 is connected to the source of Q8 and grounded. The drain of Q8 is connected to the positive pole of the digital power supply through the electromagnet under test, and the source of Q8 is connected to the negative pole of the digital power supply; The main control circuit also includes an optocoupler U3 and a switch tube Q3. The input end of the optocoupler U3 is connected to the single chip microcomputer, the output end is connected to the collector of Q3, and the base of Q3 is connected to R37 of the switch circuit to control the on and off of Q8.

2. The electromagnet temperature rise test device according to claim 1, characterized in that: The single chip microcomputer model is STM32F103.

3. The electromagnet temperature rise test device according to claim 1, characterized in that: The switching circuit includes an on-off transistor Q6, a double-pole relay coil, a double-pole relay contact mechanically connected to the double-pole relay coil, a first loop contact connected to the first test loop, and a second loop contact connected to the second test loop; The collector of Q6 is connected to the single-chip microcomputer, the emitter is connected to the double-pole relay coil, and the base is grounded. The single-chip microcomputer controls the on and off of Q6 to control the power on and off of the double-pole relay coil. The double-pole relay contacts are connected to the electromagnet to be tested. The double-pole relay coil connects the double-pole relay contact to the first loop contact or the second loop contact when it is powered on or off, thereby connecting the electromagnet to be tested to the first test loop or the second test loop.

4. The electromagnet temperature rise test device according to claim 3, characterized in that: An anti-backflow diode D12 is also connected between the emitter of Q6 and the double-pole relay coil.

5. The electromagnet temperature rise test device according to claim 1, characterized in that: The main control circuit also includes a first serial communication circuit, a second serial communication circuit, a third serial communication circuit and a fourth serial communication circuit connected to the single-chip microcomputer respectively; The first serial port communication circuit includes a first communication chip connected to the single-chip microcomputer and a first serial port connected to the first communication chip, and the first serial port is connected to a digital power supply; The second serial port communication circuit includes a second communication chip connected to the single-chip microcomputer and a second serial port connected to the second communication chip, and the second serial port is connected to the low resistance tester; The third serial port communication circuit includes a third communication chip connected to the single chip microcomputer and a third serial port connected to the third communication chip, and the third serial port is connected to the display screen; The fourth serial port communication circuit comprises a fourth communication chip connected to the single chip microcomputer and a fourth serial port connected to the fourth communication chip, and the fourth serial port is connected to the computer.

6. The electromagnet temperature rise test device according to claim 5, characterized in that: The models of the first communication chip, the second communication chip and the fourth communication chip are MAX3232, and the model of the third communication chip is MAX485.

7. The electromagnet temperature rise testing device according to claim 1, characterized in that: The main control circuit also includes a data storage circuit connected to the single chip microcomputer.

8. The electromagnet temperature rise test device according to claim 1, characterized in that: The main control circuit also includes a power supply circuit for providing a stable voltage.

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