With the growing demand for high-performance electric motors—especially in the automotive sector—motor impregnation has become a vital process. Electrified powertrains require motors with maximum power density, reduced noise emissions, and enhanced durability. Learn how motor impregnation plays a vital role in improving electrical insulation, vibration resistance, and thermal conductivity in this article!
What is motor impregnation?
Motor impregnation is a process that seals and insulates voids within electric motor components such as stators and rotors. This process involves the application of an insulating material known as impregnating resin to fill gaps within windings. By eliminating these voids, motor impregnation enhances the reliability and durability of electrical components, preventing potential breakdowns.
The impregnation process
- Preparation: The motor’s wires and windings are coated with varnish for primary insulation.
- Impregnation: There are different methods of motor impregnation, including:
- Dipping: The motor is submerged in resin, allowing it to penetrate and fill all internal voids.
- Trickling: Resin is precisely applied to the motor windings by trickling in a controlled manner. This method allows for better control over resin application, reduced waste, and faster curing.
- Curing: After impregnation, the resin is hardened through a curing process, ensuring a solid, durable insulation layer.
- Testing: The motor coil is inspected and tested for improved performance.
Why is motor coil impregnation important?
In high-voltage motors, motor impregnation helps the external coil surfaces establish strong electrical contact with the laminated core. This is crucial because air gaps between the coil and core can cause electrical discharges under high stress, leading to insulation failure—a common cause of motor breakdowns.
According to a CIGRE study, 56% of generator failures were due to insulation issues [1]. Even though only certain coils experience extreme electric stress, it is standard practice to coat all coils with a suitable impregnating resin to ensure long-term reliability.
Benefits of impregnating
Impregnation of the electrical windings of rotors and stators in the electric motor, hybrid motor, generator, hydraulic motor, pumps, or the coils in transformers or substations improves the overall performance and helps to extend the operating life of the drive train.
According to insulating function, resin impregnation of windings and copper wires provides:
- Enhanced insulation: Prevents electrical discharges and potential short circuits.
- Increased vibration resistance: Reduces mechanical stress and wear during operation.
- Improved thermal conductivity: Ensures effective heat dissipation under high-load conditions.
- Greater mechanical stability: Strengthens the motor’s structure to handle operational stresses and temperature fluctuations.
- Curing benefits: Proper curing enhances the resin’s strength, stability, and overall insulating properties.
Quality testing after motor impregnation
To verify the effectiveness of motor impregnation, components undergo rigorous testing, including:
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Electrical Properties Testing | Partial Discharge Testing | Thermal Behavior Testing | Air Voids Eliminating and Mechanical Ability Inspect |
Thus, after the impregnation process, end-products are tested and demonstrate that impregnating helps to increase insulating, thermal conductivity, and mechanical properties but contributes to a better environmental balance.
However, the result of motor impregnation can vary significantly depending on the process and materials used. For this reason, choosing the right method and materials is crucial to achieving the desired performance. Prostech offers tailored solutions to meet your specific needs, ensuring optimal results for your electric motor components.
Prostech’s electrical insulation solution for EV motors
Our solutions are designed to provide comprehensive support for the entire motor impregnation process, helping you choose the right materials and methods for maximum performance and longevity. Contact us today to find out more.
Reference: [1] CIGRE, Hydrogenerator Failures – Results of the Survey. Paris, France: CIGRE, 2003.
