As the increasingly innovated technology and processing technique improves the service life of electrical slip rings to a large degree, a normal life test fails to get the life information about the slip rings under a normal working condition in a short time.
To acquire the desired information quickly, an accelerated life test for the parts should be designed conducted in an experiment. Based on a reasonable engineering and statistical hypothesis, the accelerated experiment is to transform the information attained under an accelerated condition of exceeded stress level, by the statistical model related to failure physics. Then, it can get a recurring value evaluation of a slip ring in a rated stress level. In essence, the experiment is a method for life test to reduce the experimental cycle through enlarging its stress like temperature, brush pressure, vibration, humidity, voltage, and current etc. In this way, it improves the efficiency of tests by minimizing the time, and cutting down the costs.
According to the number of the stress type and stress change with time, there are normally three typical types: constant stress test, step stress test, and progressive stress test. As is showed below, they represent three basic types of stress loading process of accelerated life tests.