A braking resistor method for improving the reliability of a locomotive

Abstract

The present invention relates to a method for a braking resistor to improve the reliability of a locomotive, which is characterized in that it includes a plurality of traction motors, a plurality of braking resistor circuits, and a fan (9). Each traction motor corresponds to a braking resistor circuit to form a circuit. The fan (9) draws power from the resistor circuit, and the fan (9) generates cooling air to cool down the braking resistor unit (2) composed of all the braking resistor circuits. The braking resistor unit (2) includes a group of several disconnectors, which can allow the fan (9) to switch between multiple resistor circuits. When the traction motor has no fault, the fan (9) is connected in parallel to one of the resistor circuits, normally draws power to provide cooling air for the braking resistor unit (2), and the locomotive's resistor braking function is normal, improving the reliability of the resistor braking function. When one traction motor fails, it will not cause the resistor braking function of the entire locomotive to fail.

Description

Technical Field

[0001] The present invention relates to the locomotive resistance braking technology, and particularly to a braking resistance method for improving the reliability of a locomotive. Background Art

[0002] The braking resistance unit is applicable to diesel locomotives, electric locomotives, light rail locomotives, and motor cars, etc. When the locomotive performs resistance braking, each traction motor changes from the series-excited motor operation mode to the separately-excited generator operation mode, converts the kinetic energy of the locomotive into electrical energy, and the generated electrical energy is converted into heat energy through the resistance strip of the braking resistance unit. These heat energies are taken away by the cooling air formed by the fan on the braking resistance unit and dissipated into the atmosphere. At the same time, the armature winding generates a reverse braking force to decelerate the wheelset.

[0003] In engineering practice, for the consideration of reducing system complexity and energy conservation, the fans on many braking resistance units do not require additional power supply from the locomotive, but instead choose to draw power in parallel from the braking resistance circuit. Usually, one fan is configured for every two to three traction motor - braking resistance circuits. This brings a problem that when a traction motor in the traction motor - braking resistance circuit with a parallel fan has a ground fault, ring fire, or other faults, the locomotive performs the motor shedding operation. At this time, the fan of the braking resistance cannot draw power, causing the entire braking resistance unit to stop working and the locomotive resistance braking function to be unavailable. At this time, if encountering a long downhill section, the locomotive can only rely on air braking, increasing the probability of the "runaway" accident caused by locomotive braking failure.

[0004] In this existing system, a single traction motor fault will cause the entire locomotive resistance braking function to fail. The reliability models of multiple traction motor - braking resistance circuits are in a whole series structure, and the reliability of the locomotive resistance braking function is relatively low. In the existing system, when a fault occurs in the traction motor where the braking resistance fan is located, the wiring of the main circuit of the locomotive is changed emergently to ensure the reliable operation of the locomotive resistance braking function. Specifically, after the motor shedding operation, the wiring on the wiring terminal of the resistance braking cabinet needs to be removed, and the wire of the faulty traction motor is reconnected to the non-faulty traction motor. This emergency operation requires the locomotive to stop for modification, which is time-consuming and laborious and affects the line operation.

[0005] Generally, one fan is configured for every two to three traction motor - braking resistance circuits on the locomotive. The fan is connected in parallel to draw power from a braking resistance circuit to generate cooling air. When a fault occurs in the traction motor where the fan is located, the fan cannot draw power, and the entire braking resistance unit cannot work, and the locomotive resistance braking function is unavailable. At this time, if encountering a long downhill section, the locomotive can only rely on air braking, increasing the operation difficulty of the crew and the probability of the "runaway" accident caused by locomotive braking failure.

[0006] In the existing system, a fault in one traction motor will cause the entire locomotive's rheostatic braking function to malfunction. Therefore, although from a circuit perspective, multiple traction motor - braking resistor circuits are in parallel, due to its single - point fault characteristic, its reliability model is an entire series structure, and the reliability of the locomotive's rheostatic braking function is relatively low. Summary of the Invention

[0007] One of the objectives of the present invention is to provide a braking resistor method for improving the reliability of a locomotive, which can enhance the reliability of the locomotive's rheostatic braking function.

[0008] Another objective of the present invention is to provide a braking resistor method for improving the reliability of a locomotive, which can provide a braking resistor unit containing a reliability model of a parallel subsystem.

[0009] A third objective of the present invention is to provide a braking resistor method for improving the reliability of a locomotive, which can prevent the entire locomotive's rheostatic braking function from malfunctioning when one traction motor fails.

[0010] The objective of the present invention is achieved as follows. The present invention relates to a braking resistor method for improving the reliability of a locomotive, characterized in that it includes multiple traction motors, multiple braking resistor circuits, and a fan. Each traction motor corresponds to a braking resistor circuit to form a circuit; it includes a fan, which is connected in parallel to draw power from the resistor circuit, and the fan generates cooling air to cool all braking resistor circuits; it includes a group of several disconnectors, which can allow the fan to switch between multiple resistor circuits; when the traction motor has no fault, the fan is connected in parallel to one of the resistor circuits, normally draws power to provide cooling air for the braking resistor unit, and the locomotive's rheostatic braking function is normal; when the traction motor in the circuit where the fan is located fails and the locomotive needs to perform the operation of removing the motor, the disconnector acts to disconnect the fan from this circuit and switch it to the circuit where the non - faulty traction motor is located. The fan can still normally draw power to provide cooling air for the braking resistor unit, and the locomotive's rheostatic braking function is normal, thereby improving the reliability of the rheostatic braking function.

[0011] The reliability of the rheostatic braking function can be theoretically explained through a dual - circuit case: In the existing braking resistor unit, when the first traction motor in the first circuit where the fan is located fails, it will cause the entire locomotive's rheostatic braking function to malfunction. Multiple traction motors and braking resistor circuits are in a series structure, and the reliability of the locomotive's rheostatic braking function (1)

[0012] In the formula,

[0013] is the reliability of the first traction motor 5;

[0014] is the reliability of the first braking resistor circuit 6;

[0015] is the reliability of the second traction motor 7;

[0016] is the reliability of the second braking resistor circuit 8;

[0017] is the reliability of the fan 9;

[0018] In a braking resistor method for improving the reliability of a locomotive provided by the present invention, the fan can be switched in the circuit. When the first traction motor fails, the fan switches to the circuit where the second traction motor is located, and the braking resistor function of the locomotive can still work normally. The reliability of the resistance braking function of the locomotive can be expressed by formula (2):

[0019] (2)

[0020] In the formula, is the reliability of the resistance braking function of the locomotive applying a braking resistor method for improving the reliability of the locomotive provided by the present invention;

[0021] i is the i-th traction motor - braking resistor circuit;

[0022] n is the total number of n traction motor - braking resistor circuits;

[0023] is the reliability of the i-th traction motor - braking resistor circuit subsystem;

[0024] Here, two parallel subsystems are taken as an example, n = 2, so there is

[0025] (3)

[0026] After arranging formulas (1) and (3), there is:

[0027] (4)

[0028] (5)

[0029] Compare the magnitudes of formulas (4) and (5):

[0030]

[0031] (6)

[0032] Among them , , , , are all greater than 0 and less than 1, so , , , are also greater than 0 and less than 1. Therefore, Equation (6) , is greater than , that is, the reliability of the locomotive resistance braking function of the method for improving the reliability of the locomotive by using the braking resistor provided by the present invention is higher than that of the existing braking resistor unit.

[0033] The advantages of the present invention are as follows:

[0034] 1. Provide a braking resistor unit containing a reliability model of a parallel subsystem.

[0035] 2. When a traction motor in the circuit where the fan is located fails and the locomotive needs to perform an operation of removing the motor, the disconnector operates to disconnect the fan from this circuit and switch it to the circuit where the traction motor without a fault is located. The fan can still normally obtain power to provide cooling air for the braking resistor unit, and the locomotive resistance braking function is normal.

[0036] 3. Improve the reliability of the locomotive resistance braking function.

[0037] The present invention will be further described below in conjunction with the accompanying drawings of the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a schematic circuit diagram of an existing braking resistor unit and a locomotive traction unit;

[0039] Figure 2 is a reliability block diagram of the circuit of an existing braking resistor unit and a locomotive traction unit;

[0040] Figure 3 is a schematic circuit diagram of a braking resistor unit and a locomotive traction unit according to Embodiment 1 of the present invention;

[0041] Figure 4 is a reliability block diagram of the circuit of a braking resistor unit and a locomotive traction unit according to Embodiment 1 of the present invention;

[0042] Figure 5 is a schematic circuit diagram of a braking resistor unit and a locomotive traction unit according to Embodiment 2 of the present invention;

[0043] Figure 6 is a reliability block diagram of the circuit of a braking resistor unit and a locomotive traction unit according to Embodiment 2 of the present invention.

[0044] In the figure, 1 is the locomotive traction unit; 2 is the braking resistor unit; 3 is the first circuit; 4 is the second circuit; 5 is the first traction motor; 6 is the first braking resistor circuit; 7 is the second traction motor; 8 is the second braking resistor circuit; 9 is the fan; 10 is the first disconnector; 11 is the second disconnector; 12 is the third disconnector; 13 is the fourth disconnector; 14 is the third circuit; 15 is the third traction motor; 16 is the third braking resistor circuit; 17 is the fifth disconnector; 18 is the sixth disconnector. Detailed implementation manners

[0045] The following will describe in detail the implementation manners of the present invention in combination with the accompanying drawings and embodiments, so as to fully understand how the present invention uses technical means to solve technical problems and achieve the implementation process of technical effects and implement accordingly. It should be noted that as long as there is no conflict, the various embodiments in the present invention and the various features in each embodiment can be combined with each other, and the formed technical solutions are all within the protection scope of the present invention.

[0046] In order to more clearly illustrate the technical solutions of the embodiments of the present invention or the existing design methods, the following will briefly introduce the accompanying drawings required in the description of the embodiments or the existing design methods:

[0047] It should be noted that all the expressions using "first", "second", "third", "fourth", "fifth", and "sixth" in the embodiments of the present invention are used to distinguish two or three or four or six entities or parameters with the same name but different ones. It can be seen that "first", "second", "third", "fourth", "fifth", and "sixth" are only for the convenience of expression and should not be construed as a limitation on the embodiments of the present invention. This will not be repeated in the subsequent embodiments.

[0048] At the same time, in the following description, many specific details are set forth for the purpose of explanation to provide a thorough understanding of the embodiments of the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without these specific details or in the specific manner described herein.

[0049] In view of the above problems existing in the design of the existing braking resistor unit, the present invention provides a braking resistor method for improving the reliability of a locomotive, and the implementation manners of the present invention will be described through the following embodiments.

[0050] The present invention relates to a method for braking resistors to improve the reliability of a locomotive, which is characterized in that: it includes a plurality of traction motors, a plurality of braking resistor circuits, and a fan 9. Each traction motor corresponds to a braking resistor circuit to form a circuit; the fan 9 takes power from the resistor circuit, and the fan 9 generates cooling air to cool down the braking resistor unit 2 composed of all braking resistor circuits; the braking resistor unit 2 includes a group of several isolating switches, which can allow the fan 9 to switch between multiple resistor circuits; when the traction motor has no fault, the fan 9 is connected in parallel to one of the resistor circuits, takes power normally, and provides cooling air for the braking resistor unit 2, and the locomotive resistor braking function is normal; when the traction motor in the circuit where the fan 9 is located fails and the locomotive needs to perform the operation of removing the motor, the isolating switch acts to disconnect the fan 9 from this circuit and switch it to the circuit where the traction motor without fault is located. The fan 9 can still take power normally to provide cooling air for the braking resistor unit 2, and the locomotive resistor braking function is normal, improving the reliability of the resistor braking function.

[0051] Taking the double-circuit as an example, in the existing braking resistor unit 2 as shown in Figure 1 When the first traction motor 5 in the first circuit 3 where the fan 9 is located fails, it will cause the entire locomotive resistor braking function to fail. The reliability models of multiple traction motors and braking resistor circuits are in a series structure, and the reliability of the locomotive resistor braking function (1)

[0052] In the formula,

[0053] is the reliability of the first traction motor 5;

[0054] is the reliability of the first braking resistor circuit 6;

[0055] is the reliability of the second traction motor 7;

[0056] is the reliability of the second braking resistor circuit 8;

[0057] is the reliability of the fan 9;

[0058] In the method for braking resistors to improve the reliability of a locomotive provided by the present invention as shown in Figure 3 the fan 9 can be switched in the circuit. When the first traction motor 5 fails, the fan 9 switches to the circuit where the second traction motor 7 is located, and the braking resistor function of the locomotive can still work normally. The reliability of the locomotive resistor braking function can be expressed by formula (2):

[0059] (2)

[0060] In the formula, To improve the reliability of the locomotive resistance braking function of the braking resistor method provided by the present invention;

[0061] i is the i-th traction motor - braking resistor circuit;

[0062] n is the total number of n traction motor - braking resistor circuits;

[0063] is the reliability of the i-th traction motor - braking resistor circuit subsystem;

[0064] Here, two parallel subsystems are used as an example, n = 2, so there is

[0065] (3)

[0066] After arranging equations (1) and (3), we have:

[0067] (4)

[0068] (5)

[0069] Compare the magnitudes of equations (4) and (5):

[0070]

[0071] (6)

[0072] Among them 、 、 、 、 are all greater than 0 and less than 1, so 、 、 、 are also all greater than 0 and less than 1, so equation (6) , is greater than , that is, the reliability of the locomotive resistance braking function of the braking resistor method provided by the present invention to improve the reliability of the locomotive is higher than that of the existing braking resistor unit 2.

[0073] The above process of the present invention can be described by the following two embodiments:

[0074] Embodiment 1

[0075] As Figure 3 shown, this embodiment discloses a braking resistor method to improve the reliability of the locomotive, including a braking resistor unit 2, and the braking resistor unit 2 includes at least two braking resistor circuits, such as Figure 3The first braking resistor circuit 6 and the second braking resistor circuit 8 in it; among them, the first braking resistor circuit 6 and the first traction motor 5 in the locomotive traction unit 1 form a first circuit 3, and the second braking resistor circuit 8 and the second traction motor 7 in the locomotive traction unit 1 form a second circuit 4; and there is a fan 9 in the braking resistor unit 2. One side of the fan 9 is connected to one side of the first braking resistor circuit 6 through the first isolating switch 10 and to one side of the second braking resistor circuit 8 through the third isolating switch 12; the other side of the fan 9 is connected to the other side of the first braking resistor circuit 6 through the second isolating switch 11 and to the other side of the second braking resistor circuit 8 through the fourth isolating switch 13; the first isolating switch 10 and the second isolating switch 11 are normally closed, and the third isolating switch 12 and the fourth isolating switch 13 are normally open.

[0076] When the first traction motor 5 and the second traction motor 7 are working normally at the same time, the fan 9 takes power in parallel on the first braking resistor circuit 6 to provide cooling air for the braking resistor unit 2; the locomotive resistance braking function is normal; when the first traction motor 5 fails and the locomotive needs to perform the operation of removing the motor, the first isolating switch 10 and the second isolating switch 11 are disconnected, and the third isolating switch 12 and the fourth isolating switch 13 are closed. At this time, the fan 9 is disconnected from the first braking resistor circuit 6 and switched to the second braking resistor circuit 8. The fan 9 takes power normally to provide cooling air for the braking resistor unit 2, and the locomotive resistance braking function is normal.

[0077] To illustrate the improvement of the reliability of the locomotive in the embodiment of the present invention, reference can be made to Figure 4 , with the normal locomotive resistance braking function as the goal, the first braking resistor circuit 6 and the first traction motor 5 form a subsystem, and the second braking resistor circuit 8 and the second traction motor 7 form another subsystem. After these two subsystems are connected in parallel, they are connected in series with the fan 9. The reliability of this hybrid system containing parallel subsystems is higher than that of a series system with all single-point failures. The specific proof process can be seen in the foregoing invention content.

[0078] Embodiment 2

[0079] As Figure 5, a second embodiment of the present invention is given. The present invention relates to a braking resistor method for improving the reliability of a locomotive, which includes a braking resistor unit 2 and a fan 9. The braking resistor unit 2 includes at least three braking resistor circuits, such as the first braking resistor circuit 6, the second braking resistor circuit 8, and the third braking resistor circuit 16 in the figure. Among them, the first braking resistor circuit 6 and the first traction motor 5 in the locomotive traction unit 1 form a first circuit 3, the second braking resistor circuit 8 and the second traction motor 7 in the locomotive traction unit 1 form a second circuit 4, and the third braking resistor circuit 16 and the third traction motor 15 in the locomotive traction unit 1 form a third circuit 14. One side of the fan 9 is connected to one side of the first braking resistor circuit 6 through the first isolating switch 10, to one side of the second braking resistor circuit 8 through the third isolating switch 12, and to one side of the third braking resistor circuit 16 through the fifth isolating switch 17. The other side of the fan 9 is connected to the other side of the first braking resistor circuit 6 through the second isolating switch 11, to the other side of the second braking resistor circuit 8 through the fourth isolating switch 13, and to the other side of the third braking resistor circuit 16 through the sixth isolating switch 18. The first isolating switch 10 and the second isolating switch 11 are normally closed, and the third isolating switch 12 and the fourth isolating switch 13, the fifth isolating switch 17 and the sixth isolating switch 18 are normally open.

[0080] When each traction motor of the locomotive is working normally, the fan 9 takes power in parallel on the first braking resistor circuit 6 to provide cooling air for the braking resistor unit 2, and the locomotive resistance braking function is normal.

[0081] When the first traction motor 5 fails and the locomotive needs to perform the operation of removing the motor, the isolating switch acts. The first isolating switch 10 and the second isolating switch 11 are disconnected, the third isolating switch 12 and the fourth isolating switch 13 are closed, and the fifth isolating switch 17 and the sixth isolating switch 18 remain disconnected. At this time, the fan 9 is disconnected from the first braking resistor circuit 6 and switched to the second braking resistor circuit 8. The fan 9 can still take power normally to provide cooling air for the braking resistor unit 2, and the locomotive resistance braking function is normal.

[0082] When the first traction motor 5 and the second traction motor 7 fail simultaneously and the locomotive needs to perform the operation of removing the motor, the isolating switch acts. The first isolating switch 10 and the second isolating switch 11 are disconnected, the third isolating switch 12 and the fourth isolating switch 13 are disconnected, and the fifth isolating switch 17 and the sixth isolating switch 18 are closed. At this time, the fan 9 is disconnected from the first braking resistor circuit 6 and switched to the third braking resistor circuit 16. The fan 9 can still take power normally to provide cooling air for the braking resistor unit 2, and the locomotive resistance braking function is normal.

[0083] The reliability model of the embodiment can be used Figure 6It is noted that, with the aim of normal locomotive resistance braking function, the first braking resistor circuit 6 and the first traction motor 5 form a subsystem, the second braking resistor circuit 8 and the second traction motor 7 form another subsystem, and the third braking resistor circuit 16 and the third traction motor 15 form another subsystem. After these three subsystems are connected in parallel, they are connected in series with the blower 9. The reliability of this hybrid system with parallel subsystems is higher than that of a series system with all single-point failures.

[0084] Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. A braking resistor method for improving the reliability of a locomotive, characterized in that: It includes multiple traction motors, multiple braking resistor circuits, and a blower (9). Each traction motor corresponds to a braking resistor circuit to form a circuit. The blower (9) draws power from the resistor circuit, and the blower (9) generates cooling air to cool down the braking resistor unit (2) composed of all braking resistor circuits. The braking resistor unit (2) includes a group of several disconnectors, which can allow the blower (9) to switch between multiple resistor circuits. When the traction motor has no fault, the blower (9) is connected in parallel to one of the resistor circuits, draws power normally, and provides cooling air for the braking resistor unit (2), and the locomotive's rheostatic braking function is normal. When the traction motor in the circuit where the blower (9) is located has a fault and the locomotive needs to perform the operation of removing the motor, the disconnector acts to disconnect the blower (9) from this circuit and switch it to the circuit where the traction motor without fault is located. The blower (9) can still draw power normally to provide cooling air for the braking resistor unit (2), and the locomotive's rheostatic braking function is normal, improving the reliability of the rheostatic braking function.

2. The braking resistor method for improving the reliability of a locomotive according to claim 1, characterized in that: The described braking resistor unit (2) is either two braking resistor circuits, the first braking resistor circuit (6) and the second braking resistor circuit (8). Among them, the first braking resistor circuit (6) and the first traction motor (5) in the locomotive traction unit (1) form the first circuit (3), and the second braking resistor circuit (8) and the second traction motor (7) in the locomotive traction unit (1) form the second circuit (4). And there is a blower (9) in the braking resistor unit (2). One side of the blower (9) is connected to one side of the first braking resistor circuit (6) through the first disconnector (10) and to one side of the second braking resistor circuit (8) through the third disconnector (12). The other side of the blower (9) is connected to the other side of the first braking resistor circuit (6) through the second disconnector (11) and to the other side of the second braking resistor circuit (8) through the fourth disconnector (13). The first disconnector (10) and the second disconnector (11) are normally closed, and the third disconnector (12) and the fourth disconnector (13) are normally open. When the first traction motor (5) and the second traction motor (7) are working normally at the same time, the blower (9) is connected in parallel to the first braking resistor circuit (6) to draw power and provide cooling air for the braking resistor unit (2). The locomotive's rheostatic braking function is normal. When the first traction motor (5) has a fault and the locomotive needs to perform the operation of removing the motor, the first disconnector (10) and the second disconnector (11) are disconnected, and the third disconnector (12) and the fourth disconnector (13) are closed. At this time, the blower (9) is disconnected from the first braking resistor circuit (6) and switched to the second braking resistor circuit (8). The blower (9) draws power normally to provide cooling air for the braking resistor unit (2), and the locomotive's rheostatic braking function is normal.

3. The braking resistor method for improving the reliability of a locomotive according to claim 1, characterized in that: The braking resistor unit (2) is either three braking resistor circuits, namely the first braking resistor circuit (6), the second braking resistor circuit (8), and the third braking resistor circuit (16); among them, the first braking resistor circuit (6) and the first traction motor (5) in the locomotive traction unit (1) form the first circuit (3), the second braking resistor circuit (8) and the second traction motor (7) in the locomotive traction unit (1) form the second circuit (4), and the third braking resistor circuit (16) and the third traction motor (15) in the locomotive traction unit (1) form the third circuit (14). One side of the fan (9) is connected to one side of the first braking resistor circuit (6) through the first isolating switch (10), to one side of the second braking resistor circuit (8) through the third isolating switch (12), and to one side of the third braking resistor circuit (16) through the fifth isolating switch (17). The other side of the fan (9) is connected to the other side of the first braking resistor circuit (6) through the second isolating switch (11), to the other side of the second braking resistor circuit (8) through the fourth isolating switch (13), and to the other side of the third braking resistor circuit (16) through the sixth isolating switch (18). The first isolating switch (10) and the second isolating switch (11) are normally closed, and the third isolating switch (12) and the fourth isolating switch (13), the fifth isolating switch (17) and the sixth isolating switch (18) are normally open. When all the traction motors of the locomotive are working normally, the fan (9) takes power in parallel on the first braking resistor circuit (6) to provide cooling air for the braking resistor unit (2), and the resistance braking function of the locomotive is normal; When the first traction motor (5) fails and the locomotive needs to perform the operation of removing the motor, the isolating switches act. The first isolating switch (10) and the second isolating switch (11) are disconnected, the third isolating switch (12) and the fourth isolating switch (13) are closed, and the fifth isolating switch (17) and the sixth isolating switch (18) remain disconnected. At this time, the fan (9) is disconnected from the first braking resistor circuit (6) and switched to the second braking resistor circuit (8). The fan (9) can still take power normally to provide cooling air for the braking resistor unit (2), and the resistance braking function of the locomotive is normal; When the first traction motor (5) and the second traction motor (7) fail simultaneously and the locomotive needs to perform the operation of removing the motor, the isolating switches act. The first isolating switch (10) and the second isolating switch (11) are disconnected, the third isolating switch (12) and the fourth isolating switch (13) are disconnected, and the fifth isolating switch (17) and the sixth isolating switch (18) are closed. At this time, the fan (9) is disconnected from the first braking resistor circuit (6) and switched to the third braking resistor circuit (16). The fan (9) can still take power normally to provide cooling air for the braking resistor unit (2), and the resistance braking function of the locomotive is normal.

4. The braking resistor method for improving the reliability of a locomotive according to claim 1, characterized in that: The fan (9) can be switched among multiple circuits. When the first traction motor (5) fails, the fan (9) is switched to the circuit where the second traction motor (7) is located or the circuit where other traction motors are located. The braking resistor function of the locomotive can still work normally. The reliability of the resistance braking function of the locomotive can be expressed by formula (2): （2） In the formula, it is the reliability of the locomotive resistance braking function of a method for improving the reliability of the locomotive; i is the i-th traction motor - braking resistor loop; n is the total number of n traction motor - braking resistor loops; R i is the reliability of the i-th traction motor - braking resistor loop subsystem; It can be proved that the reliability of the hybrid system containing parallel subsystems represented by formula (2) is higher than that of the fully series system.

5. The braking resistor method for improving the reliability of a locomotive according to claim 2, characterized in that: The fan (9) can be switched between two loops. When the first traction motor (5) fails, the fan (9) switches to the loop where the second traction motor (7) is located, and the braking resistor function of the locomotive can still work normally. The reliability of the locomotive resistance braking function can be expressed by formula (7): （7） In the formula, it is the reliability of the locomotive resistance braking function of a method for improving the reliability of the locomotive; i is the i-th traction motor - braking resistor loop; R i is the reliability of the i-th traction motor - braking resistor loop subsystem; It can be proved that the reliability of the hybrid system containing two parallel subsystems represented by formula (7) is higher than that of the fully series system.

6. The braking resistor method for improving the reliability of a locomotive according to claim 3, characterized in that: The fan (9) can be switched between three loops. When the first traction motor (5) fails, the fan (9) switches to the loop where the second traction motor (7) is located, and the braking resistor function of the locomotive can still work normally. When the first traction motor (5) and the second traction motor (7) fail simultaneously, the fan (9) switches to the loop where the third traction motor (15) is located, and the braking resistor function of the locomotive can still work normally; The reliability of the locomotive resistance braking function can be expressed by formula (8): （8） In the formula, it is the reliability of the locomotive resistance braking function of a method for improving the reliability of the locomotive. i is the i-th traction motor - braking resistor loop; R i is the reliability of the i-th traction motor - braking resistor loop subsystem; It can be proved that the reliability of the hybrid system containing three parallel subsystems represented by formula (8) is higher than that of the fully series system.

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