Impregnating Compositions for Electrical Windings
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing impregnating compositions for electrical windings fail to provide effective electrical insulation and thermal stability at high temperatures, especially above 150°C, and are often non-homogeneous, leading to issues with storage and penetration into winding cavities.
Innovation Solution
A composition comprising 5-80 wt% polyolefin-containing unsaturated polyester resin, 0-60 wt% unsaturated polyester resin, 5-70 wt% reactive diluent, 0.01-15 wt% additives, and 0.1-20 wt% free radical initiator, which is formulated to provide excellent thermal transfer and electrical insulation properties, with adhesion and stability even at temperatures above 200°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If standard impregnating resins are used, then electrical insulation is provided at room temperature, but insulation properties decrease quickly at temperatures above 150°C
Solution Approach 1:
The patent uses a composite resin system combining epoxy resin (providing thermal stability) with unsaturated polyester resin and reactive diluents (ensuring impregnation capability). This composite approach allows the material to maintain electrical insulation properties at temperatures above 150°C while still achieving proper penetration into winding cavities during the impregnation process.
2Temperature
If epoxy systems are used to improve thermal resistance, then insulation properties at elevated temperatures improve, but viscosity increases making impregnation difficult and storage stability limited
Solution Approach 1:
The patent introduces reactive diluents (such as styrene, butyl acrylate, or hexane diol dimethacrylate) as intermediaries that reduce the viscosity of the epoxy-based resin system. These diluents enable the high-thermal-resistance epoxy resin to flow properly and penetrate into winding cavities during impregnation, while still maintaining the thermal stability benefits of the epoxy component after curing.
3Reliability
If inorganic fillers are used to improve insulation properties and thermal conductivity, then these properties improve, but the impregnation material becomes non-homogeneous causing storage and penetration problems
Solution Approach 1:
The patent carefully controls the particle size, concentration, and distribution parameters of inorganic fillers (such as silica, alumina, or titanium dioxide) within the resin system. By optimizing these parameters and using appropriate dispersants, the formulation maintains homogeneity during storage while still providing the electrical insulation and thermal conductivity benefits of the inorganic fillers.
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 composition achieves excellent electrical insulation and thermal stability at high temperatures, with improved adhesion and reduced dielectric loss, maintaining performance under humid conditions and high temperatures.
Implementation Method 1
0.1 to 20 wt% of at least one free radical initiator
Data Source
AI summary
The invention provides a composition for fixing wound items comprising A) 5 to 80 wt% of at least one polyolefin-containing unsaturated polyester resin, B) 0 to 60 wt% of at least one unsaturated polyester resin different from A), C) 5 to 70 wt% of at least one reactive diluent, D) 0.01 to 15 wt% of customary additives, and E) 0.1 to 20 wt% of at least one free radical initiator, the wt% being based on the total weight of the composition. The composition according to the invention provides excellent thermal transfer properties and a high level of electrical insulation properties under humid conditions, with excellent adhesion and thermal stability, even at high temperatures during the operation of the electrical devices, much higher than 200°C.