Thermoplastic Impregnation for Electric Machine Conductor Bars
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Solution Overview
Problem
Existing insulated conductor bars for electric machines, particularly in high-voltage generators, face challenges with lengthy curing times and hazardous, low-thermal-conductivity thermosetting resins, which hinder efficient manufacturing and performance.
Innovation Solution
The use of thermoplastic materials for impregnating conductor bars, which do not require curing and offer improved thermal conductivity, safety, and reduced processing time, achieved through a heat-vacuum-pressure process using low-viscosity precursor materials and oligomeric thermoplastics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermosetting resin is used for impregnating conductor bars, then insulation is achieved, but curing time is lengthy (hours of dwell time)
Solution Approach 1:
The patent changes the fundamental parameter of material type from thermosetting resin to thermoplastic material. This parameter change eliminates the curing process entirely, reducing processing time from hours to minutes while maintaining insulation quality through the thermoplastic material's inherent insulating properties and ability to be molded under heat and pressure.
Solution Approach 2:
The patent utilizes the phase transition properties of thermoplastic materials, which soften under heat and pressure to fill the conductor bar insulation space, then solidify upon cooling. This phase transition mechanism replaces the chemical curing process of thermosetting resins, achieving both space filling and insulation without lengthy dwell time.
2Reliability
If thermosetting resin is used for impregnating conductor bars, then insulation is achieved, but the material is hazardous and requires special precautions
Solution Approach 1:
The patent employs thermoplastic materials that are inherently safer and do not require special handling precautions. These materials can be processed and disposed of more easily compared to hazardous thermosetting resins, eliminating the need for special storage and handling infrastructure while maintaining insulation effectiveness.
Solution Approach 2:
The patent converts the previously harmful thermosetting resin into a beneficial thermoplastic material that provides the same insulation function without the hazardous properties. The thermoplastic material's ability to be reprocessed and its lack of noxious emissions turn the previously harmful material category into a beneficial alternative.
3Reliability
If thermosetting resin is used for impregnating conductor bars, then insulation is achieved, but thermal conductivity is low (0.18 W/mK for epoxy)
Solution Approach 1:
The patent utilizes thermoplastic materials that can be formulated as composites with enhanced thermal conductivity properties. By selecting appropriate thermoplastic base materials and adding thermal conductive fillers or modifiers, the insulation achieves both electrical insulation and improved heat dissipation capabilities, surpassing the thermal conductivity of traditional epoxy resins.
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
This approach significantly reduces processing time, enhances thermal conductivity by up to 30% compared to epoxy, and eliminates hazards associated with thermosetting resins, providing a safer and more efficient insulation method for electric machine conductor bars.
Implementation Method 1
a thermoplastic material in a melted state is injected into the conductor bar insulation
Implementation Method 2
The moulding tool applies a pressure
Implementation Method 3
the thermoplastic material is injected into the conductor bar insulation, where it solidifies
Implementation Method 4
the thermal conductivity of many thermoplastic materials being in the range of 0.25-0.3 W/mK... This helps to increase the thermal conductivity of the entire insulation by about 30%
Data Source
Figure 1~2
Figure 3~4
AI summary
The present disclosure relates to an insulated conductor bar, a use of a certain material for manufacturing an insulated conductor bar, and to a method for impregnating an insulated conductor bar. An object of the invention is to provide an alternative impregnation of a conductor bar for an electric machine. The invention discloses an insulated conductor bar for an electric machine having an insulation from a tape made from mica material, mica material on a glass fabric, or mica material on a polyester film, whereas a thermoplastic material is applied to the mica material or the mica material on a glass fabric.