Electric Machine Winding Insulation Using Electrostatic Resin Impregnation
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Solution Overview
Problem
The existing impregnation processes for electrical machines are inefficient due to high viscosity of reactive resins at low temperatures, leading to longer process times and potential dripping issues during impregnation, which hinder complete filling of windings and increase manufacturing complexity.
Innovation Solution
Applying a direct voltage between the winding and the body of the electrical machine creates an electrostatic capillary force that draws the multi-component reactive resin into the winding grooves, reducing process time and preventing dripping by utilizing the dielectric properties of the resin to enhance capillary forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If a multi-component reactive resin system is used at low temperatures to reduce energy consumption, then the resin has high viscosity which inhibits flow into winding grooves, but this leads to longer process times and incomplete impregnation
Solution Approach 1:
The patent applies a direct voltage field (electrical parameter change) to the resin system during impregnation. This electrical field reduces the effective viscosity of the reactive resin, enabling it to flow into the winding grooves at low temperatures without requiring high thermal energy input. The voltage parameter transformation allows the resin to achieve proper flow behavior while maintaining low process temperature.
Solution Approach 2:
The patent replaces thermal energy input (mechanical/thermal system) with electrical energy input (electrical field) to achieve resin flow. Instead of heating the resin to reduce viscosity, a direct voltage is applied between the winding and resin bath, creating an electrical field that drives the resin into the grooves through electrostatic forces, thus substituting a thermal-mechanical process with an electrical field-based process.
2Productivity
If the resin is kept at low viscosity to flow quickly into windings, then impregnation speed increases, but the resin drips out during removal from the resin bath due to lack of gelation
Solution Approach 1:
The patent employs a time-dependent process where direct voltage is applied during impregnation to maintain low effective viscosity and promote rapid resin flow into the windings. After a predetermined time period, the voltage is removed or reduced, allowing the resin to gel and solidify in place. This periodic application and removal of the electrical field enables both rapid impregnation and reliable resin retention.
Solution Approach 2:
The patent applies direct voltage during the impregnation phase to prepare the resin for optimal flow into the windings. This preliminary electrical field application ensures complete filling of the grooves before the resin is allowed to gel. The voltage is applied in advance during the critical impregnation period, and then removed to allow gelation, ensuring both complete penetration and proper retention.
3Productivity
If direct voltage is applied between winding and body to create electrostatic capillary force, then resin flow into grooves is accelerated and process time reduced, but additional equipment and process complexity are introduced
Solution Approach 1:
The patent makes the electrical connection system serve multiple functions: it provides the direct voltage for electrostatic capillary force generation, establishes electrical connection for process control, and enables both impregnation and gelation phases through voltage modulation. The same electrical infrastructure supports the entire impregnation process, reducing the need for separate dedicated equipment.
Solution Approach 2:
The reactive resin system itself responds to the applied direct voltage by reducing its effective viscosity and enabling spontaneous flow into the windings through electrostatic forces. The resin essentially serves itself by utilizing the electrical field to achieve proper distribution, eliminating the need for external mechanical pumping or heating systems. The process uses the inherent properties of the resin system activated by the electrical field.
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 method significantly reduces the impregnation time by accelerating the flow of reactive resin into the winding grooves, ensuring complete filling and minimizing air pockets, thus improving the quality of secondary insulation and streamlining the manufacturing process.
Implementation Method 1
Applying a direct voltage between the winding and the body of the electrical machine creates an electrostatic capillary force that draws the multi-component reactive resin into the winding grooves
Implementation Method 2
utilizing the dielectric properties of the resin to enhance capillary forces
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to an apparatus and a method for insulation of a body of an electric machine, said body carrying single-layer or multi-layer windings, and to an electric machine having this type of insulation. The invention first of all provides the possibility for increasing the flow speed of a reactive resin during impregnation, without negatively influencing the viscosity or the toxicity, by chemical additives, and/or the cross-linking, by temperature increase, and/or the volatility, by pressure increase, of the entire system. Rather, the properties of the system, electrical conductivity of the surrounding housing and dielectricity of the reactive resin specifically are advantageously used here without having to accept disadvantages in respect of production technology.