ESP Motor Bearing Sleeve Grounding to Prevent Seal Ring Arcing
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Solution Overview
Problem
Electrical submersible pump (ESP) motors face issues with static electrical charges building up on the insert sleeve, leading to arcing that can damage seal rings due to the lack of electrical continuity between the insert sleeve and the carrier body.
Innovation Solution
A conductive coil spring is engaged with both the insert sleeve and the carrier body, creating electrical continuity and preventing static buildup, while anti-rotation rings and lubricant ports manage radial movement and vibration reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the insert sleeve is isolated from the carrier body to reduce vibrations, then vibration transfer is reduced, but static electrical charge builds up causing arcing that damages seal rings
Solution Approach 1:
A conductive spring is introduced as an intermediary element between the insert sleeve and carrier body. The spring provides dual functionality: it maintains electrical continuity to prevent static charge buildup while its compliant nature allows relative movement to reduce vibration transfer. The spring acts as a mediator that reconciles the conflicting requirements of electrical isolation and mechanical coupling.
Solution Approach 2:
The solution changes the electrical conductivity parameter of the connection between insert sleeve and carrier body. By using a conductive spring instead of a non-conductive or rigid connection, the electrical continuity is established while maintaining the ability to isolate vibrations through the spring's elastic properties.
2Strength
If the insert sleeve is rigidly connected to the carrier body for structural stability, then structural stability is improved, but vibrations are transferred from the shaft to the stator
Solution Approach 1:
The conductive spring functions as a flexible element that maintains structural connection while allowing relative movement. The spring's elastic deformation capability enables it to absorb and isolate vibrations while maintaining the structural integrity and electrical continuity of the bearing assembly.
Solution Approach 2:
The solution transitions from a static rigid connection to a dynamic flexible connection using the spring. The spring can dynamically adjust to relative movements between the insert sleeve and carrier body, maintaining structural stability while accommodating vibration isolation through its elastic properties.
3Reliability
If electrical continuity is established between insert sleeve and carrier body, then static charge buildup is prevented, but the complexity of the bearing assembly increases
Solution Approach 1:
The conductive spring performs multiple functions simultaneously: it provides electrical continuity to prevent static charge buildup, acts as a vibration isolator through its elastic properties, and maintains the structural connection between the insert sleeve and carrier body. This multi-functionality reduces the need for additional separate components.
Solution Approach 2:
The solution merges the electrical conduction function with the mechanical connection and vibration isolation functions into a single spring element. By combining these functions, the design avoids adding separate electrical conductors and simplifies the overall bearing assembly structure.
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
Prevents static electrical discharges from occurring on the insert sleeve, protecting seal rings and maintaining motor functionality by ensuring electrical continuity and effective lubrication for vibration absorption.
Implementation Method 1
An electrically conductive spring is in engagement with the insert sleeve and with the carrier body, creating electrical continuity between the insert sleeve and the carrier body
Implementation Method 2
the spring comprises a coiled member biased into contact with the outer diameter of the insert sleeve
Implementation Method 3
Lubricant ports in the shaft, bearing sleeve and insert sleeve cause a film of lubricant to exist in the small annular spaces on the inner and outer diameters of the insert sleeve
Data Source
Figure 1~2
Figure 3
AI summary
A submersible pump electrical motor (17) has a shaft-mounted bearing sleeve (47) between first and second rotor sections (39). An insert sleeve (55) surrounds the bearing sleeve. A non-rotating carrier body (61) surrounds the insert sleeve. First and second seal rings (57a, 57b) are axially spaced apart from each other between an outer diameter of the insert sleeve and an inner diameter of the carrier body. A hole (69) in the carrier body has an inner end at the inner diameter of the carrier body. An electrically conductive coil spring (71) within the hole has an inner end protruding through the inner end of the hole into contact with the outer diameter of the insert sleeve, creating electrical continuity between the insert sleeve and the carrier body.