The Role of Interlaminate Resistance Testing in Motor Lamination Manufacturing Quality


Electric motor design & manufacturing is continually advancing towards greater efficiency and reliability. The quality of motor laminations plays a key role to achieving this goal. One of the critical tests of motor laminations is the assessment of interlaminate resistance, also known as the AB Test, as defined by ASTM A937 standards. This test procedure not only ensures the optimal performance of electric motors but also sets a new precedent in manufacturing excellence.

Interlaminate Resistance in Motor Laminations

Electric motors thrive on the seamless integration of their components, with motor laminations being the foundation that dictates overall efficiency. The Interlaminate Resistance Test (sometimes referred to as the AB Test) evaluates the electrical resistance between laminations. This evaluation ensures that the laminations, when subjected to operational loads, exhibit minimal electrical interaction, thereby safeguarding the motor's integrity and performance.


The Interlaminate Resistance Test involves a series of steps designed to simulate operational stresses on motor laminations. Starting with the removal of the protective coating to establish direct contact, the test measures resistance across the laminations. The aim is to achieve resistance readings beyond the 100 Megaohm mark, a testament to the laminations' ability to resist unwanted electrical pathways. The procedure is not just about applying pressure and recording readings; it's a sophisticated process of simulating real-world conditions to ensure that when the laminations are finally assembled into a motor core, they perform optimally.

Implications and Innovations

The ramifications of the Interlaminate Resistance Test extend beyond quality assurance. They extend to process optimization, guiding manufacturers in refining their laser cutting and coating applications. This is not merely about adhering to standards but about redefining them, pushing the boundaries of what's possible in motor lamination manufacturing. These insights fuel innovation, advancing the development of new materials and lamination designs.