This is an instrument that allows us to verify a specific property of the enamel: its mechanical resistance to friction.
With this instrument, we aim to simulate the winding of the enamelled wire (or enamelled rectangular wire) as performed by the customer, including all friction phenomena that may occur due to contact between surfaces.
In accordance with customer specifications, we are able to perform two different abrasion tests: mono-directional and bi-directional. The test most frequently requested is the bi-directional one, where the abrading element (a steel wire), in constant contact with the sample, moves continuously back and forth.
A sample is fixed at the ends of the sample holder, and the abrading element is placed in contact with the wire (or rectangular wire).
Depending on the thickness of the rectangular wire being inspected, an additional weight is identified and applied to ensure contact with the enamel to be abraded. The weight is defined according to the customer’s specification (e.g., MLS), as international standards do not define these thresholds in detail.
An electrical voltage (equal to 7.5V) is applied between the abrading element and the sample. This allows the test to be stopped when electrical contact occurs, indicating that the surface insulation is no longer present.
The number of strokes (passes) completed is the resulting output of this test. The minimum required by MLS is a function of the enamel build (the total thickness increase) deposited on the conductor.
For a “Grade 2” conductor, 50 abrasion strokes are required; for a “Grade 3”, 75 are required. Our products achieve results that are 3 times greater than these requirements!
