Low-voltage motor winding joint method

Abstract

The invention discloses a low-voltage motor winding joint method, and relates to the technical field of low-voltage motor maintenance, and the method comprises the following steps: winding a winding in advance, winding the low-voltage motor winding in a continuous winding mode without breaking the middle, and penetrating a yellow wax sleeve into a connecting line part between the windings to serve as interphase insulation; winding installation is carried out, and the wound three-phase winding is overturned back and forth in sequence and put into the motor; ending connection is conducted, and after the windings are installed, the heads and the tails of the remaining corresponding windings are connected with the leading-out wires respectively. The low-voltage motor winding joint method has the remarkable beneficial effects that the maintenance quality is effectively improved, the service life of the motor is further prolonged, and good economic benefits and practical values are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of low-voltage motor maintenance, in particular to a low-voltage motor winding connection method. Background Art

[0002] Winding failures are a common problem during the operation of low-voltage motors, often requiring a major winding overhaul. During this overhaul, the joints between winding stages are crucial. These joints are not only the key component connecting the windings to form a complete phase winding, but are also the weak link in the entire motor system. Improper joint handling can easily lead to failures, severely impacting the performance of the motor after repair, and ultimately shortening its service life.

[0003] like Figure 1 As shown in the figure, a small-capacity (less than 11 kW) four-pole motor contains four coils per phase, for a total of 12 windings. The traditional maintenance method involves winding each of the 12 windings separately and then installing them into the motor one by one. To connect the windings, a tool is used to scrape off the insulation layer on the surface of the enameled wire, and then the connections are made according to specific wiring rules. However, this traditional method has many drawbacks. During the insulation removal process, due to the difficulty in maintaining precise control, the wire cross-section is often damaged. This damage increases the wire resistance, which in turn affects current transmission efficiency, increases energy consumption during motor operation, and may even cause localized overheating during high-load operation, further damaging the windings. Insulating the joints is also a tedious task, requiring significant time and effort. The effectiveness of the insulation treatment is directly related to the safety and stability of the motor. Inadequate insulation treatment can easily lead to serious faults such as phase-to-phase short circuits. In terms of time cost, the time required for joint replacement typically accounts for more than half of the total time required to replace the motor windings, significantly extending the motor's maintenance cycle and increasing the economic losses caused by equipment downtime.

[0004] Currently, no effective solutions have been proposed for the problems in related technologies. Summary of the Invention

[0005] In response to the problems in the related art, the present invention proposes a low-voltage motor winding connection method, which aims to solve the many problems existing in the traditional winding connection method. Through innovative winding and connection methods, the efficiency and quality of low-voltage motor winding maintenance are improved, wire damage is reduced, and the insulation treatment process is simplified, thereby extending the service life of the motor.

[0006] The technical solution of the present invention is achieved as follows:

[0007] A low-voltage motor winding connection method comprises the following steps:

[0008] The winding is pre-wound, and the low-voltage motor winding is wound in a continuous winding method without interruption in the middle. Yellow wax sleeves are inserted into the connecting parts between the windings as interphase insulation;

[0009] Install the winding, turn the wound three-phase winding back and forth in turn, and put it into the motor;

[0010] Make the final connection. After the winding is installed, connect the remaining corresponding winding heads and tails to the lead wires respectively.

[0011] Furthermore, the pre-winding includes the following steps: using high-precision winding equipment and the equipped turns counter to control the number of winding turns, setting the counter target value according to the designed number of turns of the motor winding before starting the equipment, and monitoring the counter in real time during winding, and the equipment prompts when the preset number of turns is reached.

[0012] Furthermore, the pre-winding also includes the following steps: when calibrating the wire diameter changes between different windings, preparing the corresponding wire diameter enameled wire and planning the placement position, stripping off the appropriate length of insulation layer when switching the wire diameter and welding with a micro-arc welder, controlling the welding current and time, and after welding, using insulating paint to perform multi-layer insulation treatment on the welding point, and inserting the yellow wax casing after drying and curing.

[0013] Furthermore, the breakdown voltage of the insulating varnish is not less than 10 kV / mm, and the volume resistivity is not less than 1×10 14 Ω·cm.

[0014] Furthermore, the diameter of the yellow wax sleeve is 1-2 mm larger than the total diameter of the winding connection wires, and the wall thickness is 0.3-0.5 mm.

[0015] Furthermore, the material of the yellow wax sleeve is a yellow wax silk tube containing alkali-free glass fiber and silicone resin.

[0016] Furthermore, the finishing connection includes: when adopting the crimping process, the dimensional accuracy of the crimping die is ±0.05mm, and the crimping pressure is controlled within ±5% of the design value.

[0017] Beneficial effects of the present invention:

[0018] The low-voltage motor winding connection method disclosed herein significantly reduces maintenance time by eliminating a significant amount of work required to connect windings to each other. Comparative experiments have shown that compared to traditional methods, maintenance time can be reduced by approximately 58.8%, significantly improving maintenance efficiency and reducing the time cost of equipment downtime due to maintenance. In terms of maintenance quality, damage to the wire cross-section caused by scraping the insulation layer with a tool is avoided, ensuring the integrity of the wire. This reduces wire resistance, improves current transmission efficiency, and reduces energy consumption during motor operation.

[0019] At the same time, yellow wax sleeves are used as phase-to-phase insulation, which has good insulation performance and is easy to install. It effectively improves the insulation effect of the joint, reduces the probability of faults such as phase-to-phase short circuit, and ensures the safety and stability of motor operation.

[0020] In summary, the low-voltage motor winding connection method of the present invention has significant beneficial effects, effectively improves the maintenance quality, and thus extends the service life of the motor, and has good economic benefits and practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. 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 these drawings without paying any creative work.

[0022] Figure 1 1 is a schematic diagram of a conventional method for connecting windings of a low-voltage motor according to an embodiment of the present invention;

[0023] Figure 2 1 is a flow chart of a method for connecting windings of a low-voltage motor according to an embodiment of the present invention;

[0024] Figure 3 3 is a schematic diagram of the principle of a low-voltage motor winding connection method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention are within the scope of protection of the present invention.

[0026] According to an embodiment of the present invention, a low-voltage motor winding connection method is provided.

[0027] For example, a four-pole motor uses a continuous winding method, rather than the traditional method of winding each phase individually and then connecting them. Yellow wax sleeves are inserted between the windings to provide interphase insulation. During installation, the pre-wound three-phase windings are flipped back and forth and lowered into the motor in sequence. Once the windings are installed, only six ends remain, which are connected to the lead wires, eliminating the need for joints between windings.

[0028] like Figure 2-Figure 3As shown, the low-voltage motor winding connection method according to an embodiment of the present invention includes the following steps:

[0029] The low-voltage motor windings are pre-wound using a continuous winding method. Yellow wax sleeves are inserted into the connecting wires between the windings as interphase insulation. The diameter of the yellow wax sleeves is 1-2 mm larger than the total diameter of the winding connecting wires, and the wall thickness is 0.3-0.5 mm. The yellow wax sleeves are made of yellow wax silk containing alkali-free glass fiber and silicone resin.

[0030] Install the winding, turn the wound three-phase winding back and forth in turn, and put it into the motor;

[0031] After the winding is installed, the remaining winding ends are connected to the lead wires. This includes using a crimping process with a dimensional accuracy of ±0.05mm and a crimping pressure within ±5% of the design value.

[0032] In addition, the pre-winding includes the following steps: using high-precision winding equipment and the equipped turns counter to control the number of winding turns, setting the counter target value according to the designed number of turns of the motor winding before starting the equipment, and monitoring the counter in real time during winding. The equipment prompts when the preset number of turns is reached.

[0033] In addition, when calibrating the change in wire diameter between different windings, prepare the corresponding wire diameter enameled wire and plan the placement. When switching wire diameters, remove the appropriate length of insulation layer and weld with a micro-arc welder, controlling the welding current and time. After welding, use insulating varnish to insulate the welding point with multiple layers. After drying and curing, insert the yellow wax casing. The breakdown voltage of the insulating varnish is not less than 10kV / mm, and the volume resistivity is not less than 1×10 14 Ω·cm.

[0034] Specifically, when applied, the following steps are included:

[0035] Before starting to wind the winding, prepare the enameled wire and yellow wax sleeve that meet the motor specifications. Select the appropriate winding equipment and wind according to the number of turns and wire diameter requirements of the motor winding. During the winding process, ensure that the enameled wire is wound continuously without disconnection in the middle. After each winding is wound, pass the connecting wire between the winding and the next winding through the yellow wax sleeve to ensure that the yellow wax sleeve fits the connecting wire tightly and plays a good phase-to-phase insulation role. During the winding process, pay attention to the tension control of the enameled wire to avoid loose or broken wires, and ensure the quality and consistency of the winding. At the same time, strictly follow the number of turns control and wire diameter change processing methods described above to ensure the accuracy of the winding.

[0036] Move the wound three-phase winding to the motor installation location. During installation, first position the one-phase winding according to the motor's internal slot layout. Carefully flip the winding back and forth and lower it into the slot one by one, taking care to avoid scraping the winding against the motor slot wall to prevent damage to the winding insulation. Follow the same method to install the other two phase windings in place. During installation, ensure that each phase winding is positioned correctly and that the insulation between phases is good.

[0037] After all three-phase windings are installed, only six leads remain on the motor. Reliably connect these leads to the lead wires according to the motor wiring rules. Use appropriate connection techniques, such as welding or crimping, to ensure a secure connection, good contact, and resistance that meets the required values. After the connections are complete, insulate the connected parts as necessary, perhaps wrapping them with materials such as insulating tape to further enhance insulation and prevent potential safety hazards such as leakage.

[0038] Furthermore, a comparative experiment was conducted between the winding joint method of the present invention and a conventional winding joint method. Twenty 4-stage low-voltage motors under 11 kW with identical models and specifications and experiencing winding faults were randomly divided into two groups of 10. The first group was repaired using the conventional winding joint method, while the second group was repaired using the novel winding joint method. During the repair process, the repair time was recorded. After the repair, power consumption was monitored for 100 hours using a power analyzer. The number of faults was also recorded over a six-month period. The details are shown in Table 1.

[0039] Table 1 Comparative experiment comparison table

[0040] Comparison Project Traditional winding connection method Winding connection method of the present invention Mean time to repair 8.5 hours 3.5 hours Average power consumption per 100 hours 850 degrees 720 degrees Failure rate 30％ 10％

[0041] As shown in Table 1, the average repair time for conventional winding splicing methods is 8.5 hours, while the new method takes only 3.5 hours. The present invention significantly reduces repair time by eliminating the complex splicing steps required by conventional methods. The conventional method requires winding each winding individually and then scraping off the insulation for connection, a tedious and time-consuming process. The present invention utilizes continuous winding and a simple finishing connection method, significantly improving repair efficiency and reducing equipment downtime, significantly contributing to the continuity and efficiency of production. Furthermore, based on average power consumption over 100 hours, motors repaired using the conventional method consume 850 kWh, while motors repaired using the present invention consume only 720 kWh. The present invention reduces damage to the conductor cross-section and lowers conductor resistance, improving current transmission efficiency and thus reducing energy consumption. This not only saves electricity costs for enterprises but also, in the context of promoting energy conservation and emission reduction, contributes positively to improving energy efficiency for society as a whole. Furthermore, the failure rate is a key indicator of motor maintenance quality and operational reliability. The failure rate for motors repaired using traditional methods is as high as 30%, while the failure rate for motors repaired using the present invention is only 10%. This method avoids wire damage during the winding process and uses high-performance yellow wax casing as interphase insulation, effectively improving the insulation of the joints and significantly reducing the probability of faults such as interphase short circuits. This ensures the safety and stability of motor operation, reduces subsequent repair costs, and reduces production losses caused by sudden equipment failures.

[0042] In addition, it is important to note that the technical solution, when applied, is adaptable to motors of different stages as follows: For two-stage motors: Before winding, prepare enameled wire and wax sleeves of appropriate diameter based on the winding design requirements. When using continuous winding equipment, accurately set the turns counter based on the turns count of the two-stage motor windings to ensure that each winding meets the design standards. During winding installation, carefully adjust the three-phase winding's rotation angle and insertion sequence according to the motor slot layout to ensure the windings are accurately and tightly installed in the motor slots. After installation, reliably connect the remaining ends to the lead wires according to wiring rules. For six-stage motors and above: When winding, controlling the enameled wire tension during the continuous winding process is particularly critical. A professional tension adjustment device is required to ensure stable tension over the long winding process. Turn count control requires not only relying on the high-precision winding equipment's counters, but also increased manual verification frequency. Due to the complex wiring between windings, the insertion of the wax sleeve requires greater care. When installing the windings, a detailed installation sequence and operating procedures are developed based on the complex slot structure within the motor. Auxiliary tools are used when necessary to flip and install the windings. When completing the final connection, carefully distinguish the numerous leads and tails, accurately connect them to the lead wires according to the motor wiring diagram, and ensure proper insulation.

[0043] In addition, the adaptability of motors of different capacities is specifically as follows: For small-capacity (under 11 kW) non-P4 motors: Due to the motor's low power, the enameled wire may require finer diameters during winding. Care must be taken to prevent breakage of the thin enameled wire due to improper handling. When selecting wax casing, precisely match the diameter of the casing to the total wire diameter. During installation and final connections, meticulously follow the motor's actual structure and wiring guidelines.

[0044] Among them, large-capacity (11 kilowatts and above) motors: When winding the windings, use enameled wires with thicker wire diameters, which require higher-power winding equipment and more robust winding molds. During the continuous winding process, full consideration should be given to the heat dissipation of thick-diameter enameled wires. In terms of insulation treatment, in addition to using yellow wax sleeves, other insulation measures may also need to be added, such as wrapping a layer of high-performance insulating tape around the sleeve. When installing the windings, use lifting equipment for operation. When finishing the connection, use connection methods and materials that can withstand large currents, such as special copper terminal blocks for crimping, and ensure that the contact resistance of the connection parts is extremely small.

[0045] In summary, with the help of the above technical solution of the present invention, the following effects can be achieved:

[0046] The low-voltage motor winding connection method disclosed herein significantly reduces maintenance time by eliminating a significant amount of work required to connect windings to each other. Comparative experiments have shown that compared to traditional methods, maintenance time can be reduced by approximately 58.8%, significantly improving maintenance efficiency and reducing the time cost of equipment downtime due to maintenance. In terms of maintenance quality, damage to the wire cross-section caused by scraping the insulation layer with a tool is avoided, ensuring the integrity of the wire. This reduces wire resistance, improves current transmission efficiency, and reduces energy consumption during motor operation.

[0047] At the same time, yellow wax sleeves are used as phase-to-phase insulation, which has good insulation performance and is easy to install. It effectively improves the insulation effect of the joint, reduces the probability of faults such as phase-to-phase short circuit, and ensures the safety and stability of motor operation.

[0048] In summary, the low-voltage motor winding connection method of the present invention has significant beneficial effects, effectively improves the maintenance quality, and thus extends the service life of the motor, and has good economic benefits and practical value.

[0049] The foregoing is merely a preferred embodiment of the present invention and is not intended to limit the present invention. A person skilled in the art will readily appreciate other embodiments of the present invention after considering the disclosure in the specification and examples. This application is intended to cover any variations, uses, or adaptations of the present invention, which follow the general principles of the present invention and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered merely exemplary, and the true scope and spirit of the present invention are indicated by the claims.

[0050] It should be understood that the present disclosure is not limited to the exact structures that have been described above and shown in the drawings, and that various modifications and changes can be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A low voltage motor winding connection method, characterized in that: The following steps are involved: The winding is pre-wound, and the low-voltage motor winding is wound in a continuous winding method without interruption in the middle. Yellow wax sleeves are inserted into the connecting parts between the windings as interphase insulation; Install the winding, turn the wound three-phase winding back and forth in turn, and put it into the motor; Make the final connection. After the winding is installed, connect the remaining corresponding winding heads and tails to the lead wires respectively.

2. The low-voltage motor winding connection method according to claim 1, characterized in that: The pre-winding comprises the following steps: using high-precision winding equipment and an equipped turns counter to control the number of winding turns; setting a target value of the counter according to the designed number of turns of the motor winding before starting the equipment; monitoring the counter in real time during winding; and prompting the equipment when the preset number of turns is reached.

3. The low voltage motor winding connection method according to claim 2, characterized in that: The pre-winding process also includes the following steps: when calibrating the wire diameter changes between different windings, preparing enameled wires of corresponding wire diameters and planning the placement positions; when switching the wire diameters, stripping off the insulation layer of appropriate length and welding with a micro-arc welder; controlling the welding current and time; and after welding, performing multi-layer insulation treatment on the welding points with insulating varnish, and inserting the yellow wax casing after drying and curing.

4. The low voltage motor winding connection method according to claim 3, characterized in that: The breakdown voltage of the insulating varnish is not less than 10kV / mm, and the volume resistivity is not less than 1×101 4 Ω·cm.

5. The low voltage motor winding connection method according to claim 1, characterized in that: The diameter of the yellow wax sleeve is 1-2 mm larger than the total diameter of the winding connection wires, and the wall thickness is 0.3-0.5 mm.

6. The low-voltage motor winding connection method according to claim 5, characterized in that: The material of the yellow wax sleeve is a yellow wax silk tube containing alkali-free glass fiber and silicone resin.

7. The low voltage motor winding connection method according to claim 6, characterized in that: The finishing connection includes: when adopting the crimping process, the dimensional accuracy of the crimping die is ±0.05mm, and the crimping pressure is controlled within ±5% of the design value.

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