Experiments are conducted in this paper to acquire the data of the external field and the Search Coils (SCs) voltage in an eccentricity prototype motor, which can emulate different eccentricity faults of interior permanent magnetic motors (IPMSMs). By analyzing the experimental data, the pattern of the impact of the eccentricity parameters on the diagnostic signals is obtained to further form the basis of potential diagnostic methods. By comparing the values of the experimental data, it is believed that using the open-circuit external field as the diagnostic signal to carry out the diagnosis of the mixed eccentricity fault in IPMSMs can be as effective as using the SCs voltage, a well-studied diagnostic signal for that fault.