Rail traffic vehicle-mounted non-contact motor shaft voltage testing device and testing method

Abstract

The invention discloses a rail transit vehicle-mounted non-contact motor shaft voltage testing device and method. The voltage testing device comprises a sensor electrode, a supporting rod, a base, a tester and a displayer. One end of the supporting rod is fixedly connected with the sensor electrode, the other end of the supporting rod is hinged to the base, and the base is fixed to a motor end cover so that the sensor electrode can be placed in an electric field near a tested motor rotating shaft, and capacitive coupling is formed between the sensor electrode and the motor rotating shaft. The displacement current is used for measuring the voltage on the surface of the motor rotating shaft, the sensor electrode is connected with the tester through a cable, and the tester is connected with the display through a cable. The device has the advantages of being compact in structure, convenient to operate, high in reliability and the like, and the accuracy of motor rotating shaft voltage measurement is remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of motor testing, in particular to a rail transit vehicle-mounted non-contact motor shaft voltage testing device and testing method. BACKGROUND

[0002] The power system of an electrified rail transit vehicle generally adopts a converter for power supply, and a motor serves as a power output device to drive the train to move. Three-phase power supply of the converter will generate a common-mode voltage acting on the motor, which will generate a potential difference between the stray capacitances among the components in the motor, and the effect will also appear between the rotating shaft and the bearing. If the common-mode voltage is too large, the bearing will be subject to serious electric corrosion. Therefore, it is particularly important to measure the voltage between the rotating shaft and the frame (i.e., the ground) for stable operation of the vehicle. SUMMARY

[0003] The present application aims to solve the problems of the prior art and provides a rail transit vehicle-mounted non-contact motor shaft voltage testing device and testing method, which are compact in structure, convenient to operate, high in universality and safety.

[0004] To solve the above technical problems, the present application adopts the following technical scheme: A rail transit vehicle-mounted non-contact motor shaft voltage testing device comprises a sensor electrode, a support rod, a base, a tester and a display. One end of the support rod is fixedly connected with the sensor electrode, and the other end of the support rod is hingedly connected with the base. The base is fixed on a motor end cover, so that the sensor electrode is placed in the electric field near the rotating shaft of the motor to be measured. Capacitive coupling is formed between the sensor electrode and the rotating shaft of the motor. Displacement current is used to measure the voltage on the surface of the rotating shaft of the motor. The sensor electrode is connected with the tester through a cable, and the tester is connected with the display through a cable. As a further improvement of the present application, the base is internally provided with a hinged locking assembly. The hinged locking assembly comprises a first support rod, a second support rod and a third support rod. The first support rod, the second support rod and the third support rod are hingedly connected to form a Y-shaped support frame. The first support rod penetrates through the base to the outside and is hingedly connected with the support rod. A locking button is arranged on the first support rod. The second support rod and the third support rod are respectively hingedly connected with external gear wheels. A spring is arranged between the second support rod and the third support rod. An internal gear wheel is further arranged in the base. When the locking button is pressed, the first support rod is pressed down, the second support rod and the third support rod respectively drive the external gear wheels to move towards the internal gear wheel, so that the external gear wheels and the internal gear wheel are meshed with each other, and the position of the sensor electrode is locked. As a further improvement of the present application, the first supporting rod is further provided with an unlocking button, a limiting buckle and a limiting hole; the limiting buckle is engaged in the limiting hole, when the locking button is pressed, the limiting buckle and the limiting hole are both moved downward into the cavity, the cavity top is used to limit the upward movement of the limiting buckle, so as to lock the position of the first supporting rod; when the unlocking button is pressed, the limiting buckle is separated from the limiting hole and the cavity, the first supporting rod is moved upward, and the second supporting rod and the third supporting rod are synchronously moved upward, so that the outer gear is separated from the inner gear. As a further improvement of the present application, the base is internally provided with a groove, and the outer gear reciprocally moves in the groove to engage or separate from the inner gear. As a further improvement of the present application, the base is a magnetic base, and the base is externally provided with a magnetic adhesion surface. As a further improvement of the present application, the base is externally provided with a magnetic switch. As a general technical concept, the present application further provides a test method based on the above-mentioned rail transit vehicle-mounted non-contact motor shaft voltage testing device, comprising the following steps: Step S1, the base motor end cover is turned on, the supporting rod is turned to adjust the placement of the sensor electrode outside the motor rotating shaft, and the locking button is pressed to lock the position of the sensor electrode; Step S2, the sensor electrode is connected with the tester through a cable, the tester is turned on, and a coupling capacitor C x is formed between the sensor electrode and the motor rotating shaft; a voltage signal U x is generated by the weak current flowing through C0, and a voltage signal U x is generated by the weak current flowing through C0.

[0005] In the formula, U0 is the voltage signal generated by the weak current flowing through C0; C0 is the voltage of the tested voltage; U x is the voltage of the tested voltage; Step S3, C1 capacitor is connected to the tester, and the corresponding voltage U 01 is measured. Step S4, C2 capacitor is connected to the tester, and the corresponding voltage U 02 is measured. Step S5, the voltage U 01 and the voltage U 02 are brought into formula (2), and U x is calculated.

[0006] , In the formula, U 01 is the voltage measured on C0 when the capacitor C1 is connected; U 02 is the voltage measured on C0 when the capacitor C2 is connected.k The value is defined as a calibration coefficient, which is a system inherent parameter.

[0007] As a further improvement of the present application, in the step S3, the measurement is repeated five times, and the arithmetic mean value is taken ; in the step S4, the measurement is repeated five times, and the arithmetic mean value is taken .

[0008] Compared with the prior art, the present application has the following advantages: The rail transit vehicle-mounted non-contact motor shaft voltage testing device and testing method of the present application has the following advantages: the sensor electrode is placed in the electric field near the measured motor rotating shaft, and the sensor electrode and the measured motor rotating shaft are not in contact, a capacitive coupling is formed between the sensor electrode and the motor rotating shaft, the voltage on the surface of the motor rotating shaft is measured by using displacement current, the principle is simple, the operation is convenient, the reliability is high, and the current generated during the operation of the motor rotating shaft does not cause electric corrosion to the bearing and the ball, thereby improving the service life of the motor. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 Fig. 1 is a structural principle schematic diagram of the rail transit vehicle-mounted non-contact motor shaft voltage testing device in the embodiment of the present application; Figure 2 Fig. 2 is a partial structural principle schematic diagram of the rail transit vehicle-mounted non-contact motor shaft voltage testing device in the embodiment of the present application; Figure 3 Fig. 3 is a partial structural principle schematic diagram of the rail transit vehicle-mounted non-contact motor shaft voltage testing device in the embodiment of the present application from another perspective; Figure 4 Fig. 4 is a structural principle schematic diagram of the hinged locking assembly in the unlocked state in the embodiment of the present application; Figure 5 Fig. 5 is a structural principle schematic diagram of the hinged locking assembly in the locked state in the embodiment of the present application; Figure 6 Fig. 6 is a structural principle schematic diagram of the voltage testing device installed on the motor in the embodiment of the present application; Figure 7 Fig. 7 is a testing circuit principle schematic diagram in the embodiment of the present application; and Legend: 1, sensor electrode; 2, support rod; 3, base; 31, magnetic attraction fitting surface; 32, groove; 33, magnetic attraction switch; 34, cavity; 4, tester; 5, display; 6, motor rotating shaft; 7, cable; 8, hinged locking assembly; 81, first support rod; 82, second support rod; 83, third support rod; 84, outer gear; 85, inner gear; 86, locking button; 87, unlocking button; 88, limiting buckle; 89, spring; 810, limiting hole; 9, rotating shaft; 100, voltage testing device; 200, motor end cover. DETAILED DESCRIPTION

[0010] The application will be further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the protection scope of the application is not limited by this.

[0011] In the description of the application, it should be understood that the orientation or positional relationship indicated by the terms "side", "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application.

[0012] In addition, the terms "first" and "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features, so that the features with "first" and "second" can explicitly or implicitly include one or more of the features, and in the description of the application, the meaning of "multiple" is two or more, unless otherwise explicitly and specifically limited.

[0013] EMBODIMENT As Figure 1 , Figure 2 and Figure 3As shown, the rail transit vehicle-mounted non-contact motor shaft voltage testing device of the present application comprises a sensor electrode 1, a support rod 2, a base 3, a tester 4 and a display 5. The display 5 can adopt an LED display to display the testing results in real time. One end of the support rod 2 is connected and fixed with the sensor electrode 1, and the other end of the support rod 2 is hingedly connected with the base 3, which is fixed on the motor end cover 200, so as to place the sensor electrode 1 in the electric field near the measured motor rotating shaft 6, form a capacitive coupling between the sensor electrode 1 and the motor rotating shaft 6, and measure the voltage on the surface of the motor rotating shaft 6 by using displacement current. The sensor electrode 1 is connected with the tester 4 through a cable 7, and the tester 4 is connected with the display 5 through the cable 7. Compared with the contact type shaft voltage testing device, the voltage testing device of the present embodiment does not bring about extra load effect on the vehicle operation, can be applied to traction motors with different shaft diameters, and is simple to install, and the non-contact measurement greatly improves the safety of measurement during motor operation.

[0014] As shown in Figure 1 , Figure 2 and Figure 3 , the support rod 2 comprises upper and lower two parts which are hingedly connected, the upper part is connected and fixed with the sensor electrode 1, and the cable 7 is arranged in the upper part, and the lower part is hingedly connected with the base 3. The relative position between the sensor electrode 1 and the motor rotating shaft 6 is adjusted by rotating the support rod 2.

[0015] As shown in Figure 4 and Figure 5 , the base 3 is internally provided with a hinged locking assembly 8, the hinged locking assembly 8 comprises a first support rod 81, a second support rod 82 and a third support rod 83, the first support rod 81, the second support rod 82 and the third support rod 83 are hingedly connected to form a Y-shaped support frame, the first support rod 81 penetrates to the outside of the base 3 and is hingedly connected with the support rod 2, the top of the first support rod 81 is provided with a locking button 86, the second support rod 82 and the third support rod 83 are respectively hingedly connected with an external gear 84, a horizontal spring 89 is arranged between the second support rod 82 and the third support rod 83 for connection, and the base 3 is internally provided with an internal gear 85. When the locking button 86 is pressed, the first support rod 81 is pressed downward, the second support rod 82 and the third support rod 83 respectively drive the external gear 84 to move towards the internal gear 85, so that the external gear 84 and the internal gear 85 are engaged with each other, and the position of the sensor electrode 1 is locked.

[0016] As shown in Figure 4 and Figure 5As shown, the first supporting rod 81 is further provided with an unlocking button 87, a limiting buckle 88 and a limiting hole 810; the two unlocking buttons 87 are connected by a spring, and the connecting rods of the two unlocking buttons 87 are cross-connected and hinged at the cross-connection, forming a structure similar to a pair of scissors. The limiting buckle 88 is clamped in the limiting hole 810. When the locking button 86 is pressed, the limiting buckle 88 and the limiting hole 810 are both moved downward into the cavity 34, and the top of the cavity 34 is used to limit the upward movement of the limiting buckle 88 to lock the position of the first supporting rod 81, and then lock the position of the sensor electrode 1. When the unlocking button 87 is pressed, the limiting buckle 88 is separated from the limiting hole 810 and the top of the cavity 34, the first supporting rod 81 moves upward, and the second supporting rod 82 and the third supporting rod 83 move upward synchronously to make the outer gear 84 disengage from the inner gear 85, so as to unlock the position of the sensor electrode 1, prevent loosening due to vibration during real vehicle detection, and thus affect the measurement accuracy. Further, the base 3 is internally provided with a groove 32, and the outer gear 84 reciprocally moves in the groove 32 to engage or disengage the inner gear 85. Through the limiting action provided by the groove 32, the accuracy of the movement of the outer gear 84 is improved, the accurate engagement or disengagement of the outer gear 84 and the inner gear 85 is realized, and the relative position between the sensor electrode 1 and the motor shaft 6 is accurately controllable.

[0017] As shown in Figure 3 The base 3 is a magnetic base, and the outer side of the base 3 is provided with a magnetic adhesion surface 31 which can be adsorbed on the surface of the motor end cover 200. The base 3 is provided with a magnetic adhesion switch 33. By opening or closing the magnetic adhesion switch 33, the convenience of disassembling and assembling the base 3 is improved.

[0018] In this embodiment, one end of the supporting rod 2 is connected and fixed with the sensor electrode 1, the other end of the supporting rod 2 is hinged with the base 3, and the base 3 is fixed on the motor end cover 200. That is, the sensor electrode 1 is placed in the electric field near the measured motor shaft 6, the sensor electrode 1 does not contact the measured motor shaft 6, a capacitive coupling is formed between the sensor electrode 1 and the motor shaft 6, the displacement current is used to measure the voltage on the surface of the motor shaft 6, and the method has the characteristics of simple principle, convenient operation and high reliability. The method avoids the electric corrosion of the current generated during the operation of the motor shaft 6 on the bearing and the ball, and improves the service life of the motor.

[0019] In this embodiment, a test method based on the above-mentioned rail transit vehicle-mounted non-contact motor shaft voltage testing device is also provided, which includes the following steps: Step S1, the base 3 is mounted on the motor end cover 200, and the supporting rod 2 is rotated to adjust the placement of the sensor electrode 1 outside the motor shaft 6, and the locking button 86 is pressed to lock the position of the sensor electrode 1. The voltage testing device 100 is mounted and fixed on the motor end cover 200 as shown in Figure 6 .

[0020] Step S2, connect the sensor electrode 1 with the tester 4 through the cable 7, turn on the tester 4, and form a coupling capacitor C between the sensor electrode 1 and the motor shaft 6 x ; pass the coupling capacitor C x Form a voltage divider circuit U0 between the measuring device and the ground, as shown in Figure 7 ;

[0021] In the formula, U0 is the voltage signal generated by the weak current flowing through C0; C0 is the voltage dividing capacitor of the tester 4; U x is the measured voltage.

[0022] C0 is a known quantity, and U0 is a detected quantity. After knowing C x , U x can be calculated by formula (1).

[0023] Since C x is greatly affected by the actual test environment (the distance between the test electrode plate and the shaft, air temperature, humidity, etc.), its equivalent capacitance is variable, so two known capacitors C1 and C2 are connected in series in the circuit to obtain the U 01 and U 02 values of each test in real time, which can eliminate the influence of the change of C x on the test results.

[0024] Step S3, connect the C1 capacitor to the tester 4 and measure the corresponding voltage U 01 . Further, repeat the measurement five times and take the arithmetic mean to improve the measurement accuracy.

[0025] Step S4, connect the C2 capacitor to the tester 4 and measure the corresponding voltage U 02 . Further, repeat the measurement five times and take the arithmetic mean to improve the measurement accuracy.

[0026] Step S5, bring the voltage U 01 and the voltage U 02 into formula (2) to calculate U x ,

[0027] , In the formula, U 01 is the voltage measured on C0 when the C1 capacitor is connected; U 02 is the voltage measured on C0 when the C2 capacitor is connected. kThe value is defined as a calibration coefficient, and is a system inherent parameter, which can be obtained by selecting appropriate C1, C2 and C0 capacitors in advance.

[0028] The above merely describes the preferred embodiments of the present application, and the protection scope of the present application is not limited to the above-mentioned embodiments. Any technical scheme falling within the concept of the present application shall fall within the protection scope of the present application. It should be noted that, for ordinary skilled persons in the art, some improvements and refinements without departing from the principles of the present application shall also be considered as falling within the protection scope of the present application.

Claims

1. A rail transit vehicle-mounted non-contact motor shaft voltage testing device, characterized in that, It includes sensor electrode (1), support rod (2), base (3), tester (4) and display (5); one end of support rod (2) is connected with sensor electrode (1), the other end of support rod (2) is hinged with base (3), base (3) is fixed on motor end cover (200), so that sensor electrode (1) is placed in the electric field near the motor rotating shaft (6), capacitor coupling is formed between sensor electrode (1) and motor rotating shaft (6), displacement current is used to measure the voltage on the surface of motor rotating shaft (6), sensor electrode (1) is connected with tester (4) through cable (7), tester (4) is connected with display (5) through cable (7). The inside of base (3) is provided with hinged locking assembly (8), hinged locking assembly (8) includes first support rod (81), second support rod (82) and third support rod (83), first support rod (81), second support rod (82) and third support rod (83) are hinged to form Y-shaped support frame, and first support rod (81) penetrates to the outside of base (3) and is hinged with support rod (2), locking button (86) is arranged on first support rod (81), second support rod (82) and third support rod (83) are hinged with outer gear (84) respectively, spring (89) is arranged between second support rod (82) and third support rod (83), inner gear (85) is further arranged in base (3); when locking button (86) is pressed, first support rod (81) is pressed down, second support rod (82) and third support rod (83) drive outer gear (84) to move towards inner gear (85) respectively, so that outer gear (84) and inner gear (85) are engaged with each other, the position of sensor electrode (1) is locked.

2. The non-contacting electric machine shaft voltage testing device for a rail vehicle of claim 1, wherein, Unlocked button (87), limiting buckle (88) and limiting hole (810) are further arranged on first support rod (81); limiting buckle (88) is engaged in limiting hole (810), when locking button (86) is pressed, limiting buckle (88) and limiting hole (810) are both moved into cavity (34), the top of cavity (34) is used to limit the upward movement of limiting buckle (88), so as to lock the position of first support rod (81); when unlocked button (87) is pressed, limiting buckle (88) is separated from limiting hole (810) and cavity (34), first support rod (81) moves upward and drives second support rod (82) and third support rod (83) to move upward synchronously, so that outer gear (84) is separated from inner gear (85).

3. The non-contacting on-board metro electrical machine shaft voltage testing device according to claim 2, characterized in that, The inside of base (3) is provided with recess (32), outer gear (84) reciprocates in recess (32) to engage or separate from inner gear (85).

4. The non-contacting electric machine shaft voltage testing device for a rail vehicle of claim 2, wherein, The base (3) is a magnetic base, and the outer side of the base (3) is provided with a magnetic adhesion surface (31).

5. The non-contacting on-board metro electrical machine shaft voltage testing device according to any one of claims 1 to 4, characterized in that, The base (3) is provided with a magnetic switch (33).

6. The non-contacting on-board metro electrical machine shaft voltage testing device according to claim 5, characterized in that, The following steps are included:

7. A testing method based on the contactless electric machine axle voltage testing device for rail transit vehicles according to any one of claims 1 to 6, characterized in that, Step S1, place the base (3) on the motor end cover (200), rotate the support rod (2) to adjust the placement of the sensor electrode (1) outside the motor rotating shaft (6), and press the locking button (86) to lock the position of the sensor electrode (1); ​ Step S2, connect the sensor electrode (1) with the tester (4) through the cable (7), turn on the tester (4), and form a coupling capacitor C between the sensor electrode (1) and the motor shaft (6) x ; through the coupling capacitor C x A voltage divider circuit U0 is formed between the measuring device and the ground In the formula, U0 is the voltage signal generated by the weak current flowing through C0; C0 is the voltage dividing capacitor of the tester (4); U x is the measured voltage; Step S3, connect the C1 capacitor to the tester (4), and measure the corresponding voltage U 01 ; Step S4, connect C2 capacitor to the tester (4), and measure the corresponding voltage U 02 ; Step S5, the voltage U 01 and the voltage U 02 are entered into equation (2), and U x is calculated, ， where U 01 The voltage on C0 is measured when the capacitor C1 is connected; U 02 The voltage on C0 is measured when the capacitor C2 is connected; k The value is defined as a calibration coefficient, which is a system inherent parameter.

8. The test method of claim 7, wherein, In the step S3, the measurement is repeated five times and the arithmetic mean is taken In the step S4, the measurement is repeated five times and the arithmetic mean is taken .

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