Bisimide Phenol Resin for Low Dielectric Traction Motor Insulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge is to develop a low dielectric-constant insulation coating material for traction motors that prevents partial discharge and dielectric breakdown, particularly in high-voltage applications where thicker insulation coatings increase size and electrical resistance, contradicting the goal of compactness and high-power output.
Innovation Solution
A novel bisimide phenol compound and its derivatives, including bisimide phenyl ester acid dianhydride, polyamic acid, and polyimide, are developed with specific structural features to create a resin composition with a low dielectric constant, suitable for use as an insulation coating in traction motors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the insulating resin is increased to prevent partial discharge, then the insulation performance is improved, but the volume fraction of the conductor decreases and the traction motor size increases
Solution Approach 1:
The invention changes the dielectric constant parameter of the insulating resin from conventional values (typically 2.5-3.5) to a lower value (2.0 or less). This parameter change allows the insulation coating to maintain adequate thickness for preventing partial discharge while occupying less volume, thus preventing traction motor size increase
Solution Approach 2:
The invention uses a composite resin system comprising a polyimide base resin and a specific low-dielectric-constant compound (Formula 1) with hydroxy groups. This composite material achieves both the low dielectric constant requirement and the insulation performance needed to prevent partial discharge, resolving the contradiction between insulation effectiveness and compactness
2Reliability
If the thickness of the insulating resin is increased to prevent partial discharge, then the insulation performance is improved, but the electrical resistance increases
Solution Approach 1:
By changing the dielectric constant parameter to a lower value (2.0 or less) through the use of the specific resin composition, the electric field distribution is optimized. This allows for reduced insulation thickness while maintaining adequate electrical insulation performance, thereby preventing excessive electrical resistance and associated energy losses
3Strength
If inorganic filler is added to suppress erosion due to partial discharge, then the erosion resistance is improved, but the dielectric constant increases
Solution Approach 1:
Instead of adding inorganic filler to improve erosion resistance (the conventional approach), the invention inverts the approach by developing an organic resin composition with specific molecular structure (Formula 1) that inherently provides both low dielectric constant and resistance to partial discharge erosion. This eliminates the need for inorganic fillers that would increase the dielectric constant
Solution Approach 2:
The invention changes the chemical structure parameter of the resin by introducing the specific compound of Formula 1 with hydroxy groups and imide rings. This structural parameter change provides both the low dielectric constant and the erosion resistance normally requiring inorganic fillers, thus avoiding the trade-off between erosion resistance and dielectric constant
Data Source
AI summary
A bisimide phenyl ester acid dianhydride represented by the following formula (2):where R3 and R4 each independently represents a hydrogen atom or an organic group having 1 to 10 carbon atoms; each m is independently an integer of 1 to 4; and each A independently represents an aromatic ring or an alicyclic ring.