Borehole Pump Stator Coil Layout for Axial Replacement

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Solution Overview

Problem

The manufacture of borehole pumps, particularly the coils of their motors, is complex and costly, especially when using insulated submarine cables, and repairs are difficult due to limited space, leading to time-consuming installation and high costs.

Innovation Solution

The design features axially extending teeth and grooves on the stator that allow coils to be easily pushed onto and off the stator, enabling efficient manufacturing and replacement, with the second axial coil end bent to radially enclose a tooth, facilitating axial insertion and removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If insulated submarine cables are used for coil windings, then reliability is improved, but manufacturing time increases to up to 16 hours and manufacturing complexity increases

Engineering Contradiction:
Improvecoil reliabilityVSAvoidmanufacturing speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The coil structure is segmented into multiple independent coils that can be manufactured separately and installed individually. Each coil is inserted into its own groove between stator teeth, allowing parallel manufacturing and installation processes, thereby reducing total manufacturing time while maintaining reliability through proper insulation of each segment.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Coils are pre-assembled with insulation and terminal connections before insertion into the stator. The second axial coil end is pre-bent to facilitate insertion, and insulation layers are applied in advance during coil manufacturing, reducing on-site assembly time and complexity while ensuring reliable insulation.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If insulated submarine cables are used for coil windings, then reliability is improved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvecoil reliabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The motor winding system is divided into multiple independent coils that can be manufactured using standard insulation techniques rather than requiring complex submarine cable assembly processes. Each coil is insulated independently and inserted into separate grooves, simplifying the overall manufacturing process while maintaining reliable insulation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Standard insulation materials and methods are used as intermediaries between the coil windings and the operational environment, replacing the need for complex insulated submarine cables. The insulation layers and groove structures serve as mediators that provide the necessary electrical isolation with simpler, more cost-effective materials and processes.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If coils are traditionally installed in the stator, then manufacturing is completed, but repair during operation is not possible due to limited space

Engineering Contradiction:
Improvecoil installationVSAvoidcoil repairability
Core Design Contradiction:
Ease of manufactureVSEase of repair

Solution Approach 1:

The winding system is segmented into multiple independent coils that can be individually accessed and removed through the axial ends of the stator. Each coil is housed in its own groove and can be independently replaced without affecting other coils, enabling field repair and replacement in the limited space of a borehole pump installation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The coil installation structure is designed to be dynamically reversible, allowing coils to be inserted and removed axially during operation. The bent second axial coil end and groove configuration enable easy insertion during manufacturing and equally easy removal during maintenance, transforming a static installation into a dynamically serviceable system.

Inventive Principle:
Principle #15Dynamics

4Ease of operation

If the second axial coil end is bent to radially enclose a tooth, then ease of insertion is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvecoil insertionVSAvoidcoil positioning precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The stator structure is segmented into multiple teeth with defined grooves between them, providing discrete positioning references for each coil. The bent second axial coil end is designed to engage with specific geometric features of the teeth and grooves, creating self-aligning positions that reduce the impact of manufacturing tolerances while facilitating easy insertion.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The groove structures between stator teeth are designed to provide equipotential positioning zones where coils naturally settle into correct positions during insertion. The geometric configuration of the grooves and bent coil ends creates a self-correcting system that minimizes the effect of manufacturing variations on final coil positioning.

Inventive Principle:
Principle #12Equipotentiality

Data Source

PatentEP4202224B1Downhole pump
Publication Date: 2025.07.02 WILO SE
  • EP4202224B1 patent drawingFigure 1
  • EP4202224B1 patent drawingFigure 2
  • EP4202224B1 patent drawingFigure 3

AI summary

The invention relates to a borehole pump with an axially extending stator (1), an axially extending rotor (6) arranged in the stator (1) and radially enclosed by the stator (1), and a plurality of coils (3) each having a first axial coil end (4) and an opposing second axial coil end (5), wherein the stator (1) is alternately formed with a plurality of axially extending teeth (2) facing the rotor (6), each with a first axial tooth end (8) and an opposing second axial tooth end (9), and axially extending grooves (7) projecting radially back between two adjacent teeth (2) for receiving the coils (3), the respective second axial coil end (5) being bent in the region of the second axial tooth end (9) and thereby arranged radially offset from the first axial coil end (4) towards the rotor (6) to radially enclose at least one tooth (2).and the respective first axial coil end (4) axially encloses at least one first axial tooth end (8) and the respective second axial coil end (5) axially encloses at least one second axial tooth end (9).