Form-Wound ESP Motor Stator With Nested Hairpin Conductors
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Solution Overview
Problem
Conventional sew-through winding methods for electric submersible pump motors are lengthy, damage-prone, and lack precision, especially for long motors with small stator bore diameters, leading to potential conductor damage and reduced power density.
Innovation Solution
A form-wound stator winding method using pre-formed rectangular conductors that are nested and inserted into closed stator slots, allowing for automated or semi-automated processes with precise conductor placement and reduced risk of damage, utilizing methods like brazing or laser welding for joining, and enabling improved insulation and copper fill ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional sew-through winding method is used, then the process can be completed with simple equipment, but the manufacturing cycle time is lengthy and conductor damage risk is high
Solution Approach 1:
The conductors are pre-formed into hairpin shapes with predetermined bends and configurations before insertion into the stator slots. This preliminary forming action eliminates the need for complex on-site winding operations, significantly reducing manufacturing cycle time while preventing conductor damage that would occur during repeated handling and bending in conventional methods
Solution Approach 2:
The winding process is segmented into distinct operations: pre-forming conductors separately, preparing slots independently, inserting pre-formed hairpins, and performing joining operations separately. This segmentation allows each operation to be optimized independently, reducing overall cycle time and minimizing conductor damage risk by eliminating repeated handling
2Manufacturing precision
If conventional sew-through winding method is used, then the process is simpler, but the precision of conductor placement is poor
Solution Approach 1:
Conductors are pre-formed into precise hairpin configurations with exact bend angles and positions before insertion. This preliminary precision work ensures that when conductors are inserted into stator slots, they achieve accurate placement without requiring complex adjustment mechanisms or skilled manual manipulation during assembly
Solution Approach 2:
The conductor cross-section is changed from round to rectangular hairpin shape, and the winding method transitions from continuous sewing to discrete insertion. This parameter change enables precise positioning through geometric compatibility between the rectangular hairpin and slot geometry, achieving high placement precision with simpler insertion equipment
3Quantity of substance
If form-wound conductors with rectangular cross-sections are used, then copper fill ratio and compactness are improved, but the manufacturing process becomes more complex
Solution Approach 1:
The conductor cross-section is changed from round to rectangular hairpin shape, which allows tighter packing in stator slots and improves copper fill ratio. The rectangular geometry provides better nesting characteristics and compactness. Although pre-forming equipment is introduced, the overall process complexity is reduced by eliminating complex sewing operations and enabling automated insertion
Solution Approach 2:
The pre-formed rectangular hairpin conductors are designed to nest efficiently within stator slots and around each other in the end regions. This nesting arrangement maximizes copper fill ratio and achieves compact motor design, while the standardized hairpin geometry simplifies the insertion process compared to conventional winding methods
4Reliability
If sew-through winding method is used, then equipment requirements are simpler, but conductor work hardening and integrity damage occur
Solution Approach 1:
Conductors are pre-formed into final hairpin configurations in a controlled environment using specialized equipment that minimizes mechanical stress. This preliminary action prevents the repeated bending and handling that causes work hardening and conductor damage in conventional sew-through methods, thereby improving conductor integrity and reliability
Solution Approach 2:
The manufacturing process is segmented so that conductor forming, slot preparation, insertion, and joining are separate operations. This segmentation eliminates the need for repeated conductor handling and bending during assembly, reducing work hardening and maintaining conductor integrity, while each segment can be optimized for simplicity in its specific operation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enhances manufacturability by reducing cycle times, improving conductor integrity, and increasing power density through precise winding and insulation application, while minimizing damage and work hardening of conductors.
Implementation Method 1
The joining of conductors can use a variety of methods including but not limited to brazing and laser welding or a combination
Implementation Method 2
The joining of conductors can use a variety of methods including but not limited to brazing and laser welding or a combination
Data Source
AI summary
Disclosed is an apparatus According to the present invention, a new winding arrangement was developed to enhance the manufacturability of stators with large length to diameter ratio and small aperture diameters such as the ones designed and manufactured for downhole pumping applications. The rectangular conductors are pre-formed to a specific shape, nested together, and inserted into the stator slots. Once the conductors are inserted, additional bending and joining operations are required to complete the coils and phases. These operations can be either fully automatic or semi-automatic. The structure of the winding allows insertion of phase and phase to phase insulation after the joining operation is completed thus reducing the risk of damage to the insulation system during the joining process. The pre-formed winding due to its ability to nest by design results is very short end-turns compared to conventional winding.