Swellable EPDM Packing Ring for Stator Wire Retention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing stator magnet wire retention systems in electric motors, particularly in high-temperature applications like ESP motors, rely on encapsulants like varnish or epoxy that degrade and fail to restrain wires effectively at elevated temperatures.
Innovation Solution
A stator magnet wire retention system utilizing an annular coil packing ring made of ethylene propylene diene monomer (EPDM) rubber that swells upon exposure to lubricant, providing radial pressure to restrain end turns and avoiding pressure points, combined with a rigid annular pressure ring for additional support, eliminating the need for encapsulants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If encapsulants such as varnish or epoxy are used to restrain magnet wires, then the wires are held in place effectively at normal temperatures, but the encapsulants degrade and fail at high temperatures
Solution Approach 1:
The patent changes the physical state of the retention system by using a swellable material that transforms from a non-swollen to a swollen state upon contact with lubricant. This parameter change (volume expansion) enables the retention ring to exert sufficient pressure on the magnet wires at high temperatures without degrading, replacing the temperature-sensitive encapsulants with a temperature-resistant swellable material.
Solution Approach 2:
The retention ring is pre-installed in a non-swollen state within the stator, and the swelling action is triggered automatically when lubricant is introduced during motor operation. This preliminary positioning combined with subsequent activation ensures the retention mechanism is ready before high-temperature conditions occur and activates precisely when needed.
2Strength
If a rigid structure is used to restrain end turns, then stable support is provided, but pressure points are created that can damage wires
Solution Approach 1:
The patent employs a flexible swellable material for the retention ring that can conform to the contours of the stator and magnet wire arrangement. This flexibility allows the ring to provide uniform distributed pressure across multiple contact points rather than concentrated pressure points, preventing wire damage while maintaining effective retention.
Solution Approach 2:
The swellable material inherently provides a cushioning effect as it expands gradually upon contact with lubricant, distributing the retention force evenly. This cushioning action prevents sudden or concentrated pressure on the magnet wires while still providing firm retention once fully swollen.
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
The system effectively retains magnet wires without encapsulants, maintaining stability and preventing wire movement even at high temperatures, thus enhancing the reliability and longevity of electric motors.
Implementation Method 1
The coil packing ring can include a packing ring cylinder and a packing ring flange, at least a portion of the packing ring cylinder being positioned concentrically within the winding inner diameter and the packing ring flange being positioned proximate to the plurality of end turns
Data Source
AI summary
The invention includes a retention system and method for stator magnet wires. In embodiments, the retention system includes a packing ring that can swell to a larger size following installation. In embodiments, the lubricant used in the motor causes the packing ring to swell. When the packing ring swells, it exerts pressure against the end turns of the stator magnet wires, and can contour to the shape of the wires so that there are no pressure points on the wires. A rigid support ring can be positioned concentric with the packing ring so that the packing ring does not swell toward the axis of the motor housing.