Before determining any test procedures for core loss and core degradation, it is important to understand the nature of the steel properties. Iron-containing materials have a variety of electrical, magnetic, and mechanical properties that must be taken into account in the design of electrical equipment. The purpose of the design is usually to maximize output while minimizing associated electrical and mechanical losses.
　　There are two types of tests to determine the total iron loss of a motor core, the first of which is known as the separation loss method described in the Institute of Electrical and Electronics Engineers (IEEE) standard and the Canadian Standards Association standard. Using linear regression analysis and various percentage load characteristics, this test method determines the total loss and the subject motor efficiency. This type of test is more effective than other types of tests when the exact nature of the core losses of the entire motor system is needed. However, the main motor must be in complete working condition. This limits its use to motor repairs that can be classified as preventive maintenance repairs.
　　Second, the test procedure must be performed in a laboratory controlled environment. Laboratory subcontracting core loss testing dedicated to motor testing is a costly and time consuming undertaking. It is conservatively estimated that the time and cost of the isolation loss test is approximately one day per day for more than ,000 per engine, which further reduces the motor to non-emergency failure.