Ensuring Motor Lamination Quality with the Franklin Test


The Franklin Test, governed by ASTM A717, is a critical assessment tool for ensuring the integrity and performance of motor lamination coatings. It evaluates the electrical resistance of coatings applied to motor laminations, a factor that significantly influences the efficiency and longevity of electric motors.

What is the Franklin Test?

The Franklin Test is a specialized procedure designed to measure the electrical resistance of a coating on a metallic substrate. By piercing through the coating and conducting electricity, the test determines the surface resistance, providing insights into the coating's effectiveness and uniformity. The ability to perform this test at varying pressures and temperatures enhances its versatility, allowing for a comprehensive evaluation under different conditions as specified by ASTM A717.


The process begins with the specimen being loaded into the Franklin tester. Upon initiating the test, the device records the amperage reading, with lower values indicating higher resistance levels. This direct correlation between amperage and resistance is key as it quantifies the coating's capacity to insulate the underlying material.

Multiple readings are taken across various sections of the sample material. This thorough approach ensures a detailed assessment, highlighting any inconsistencies or deficiencies in the coating application. Such precision is particularly beneficial for Laser Technologies, enabling them to guarantee the highest quality standards in their products.

Implications for Motor Lamination Manufacturing

The Franklin Test's ability to accurately measure coating resistance has profound implications for the manufacturing of motor laminations:

Quality Assurance

It provides a quantitative measure of coating integrity, ensuring that only materials meeting stringent standards are used in production.

Process Optimization

Insights gained from the test can inform process adjustments, enhancing coating application techniques for better uniformity and performance.

Product Performance

By ensuring optimal coating resistance, the test contributes to the overall efficiency and reliability of the final motor, reducing electrical losses and improving thermal management.

Innovation and Development

The data derived from Franklin Testing can drive material innovation, leading to the development of new coatings that offer superior resistance and longevity.

For companies like Laser Technologies, adopting such standardized testing procedures underscores a commitment to excellence and innovation, setting new benchmarks in the motor manufacturing industry. As technology advances, the Franklin Test will continue to be an indispensable tool in the quest for superior motor lamination coatings, driving improvements in electric motor performance and sustainability.