On-line diagnosis of high-resistance connection for inverter fed induction motors

An on-line method for high-resistance connection (HRC) diagnosis in induction motors (IM) incoming circuit is presented in this effort. This automatic method is based on a signal injection strategy. It is possible to detect, evaluate the severity and determine the physical location of a HRC problem by using an exploratory signal injected to the IM. In order to validate the proposed method experimental studies were carried out in a laboratory set-up. Results showed high sensitivity of the method for detecting HRC, as well as a low error which indicates a high accuracy in the estimation of HRC. In addition, results have demonstrated the possibility to identify the IM phase affected by the HRC failure.