More attention in multiphase permanent magnet (PM) synchronous motors is increasing gradually due to the high power requirement of some applications including traction, aerospace, defense and so on. These motors have a fault-tolerant capability when the utilization of winding is achieved. In this paper, performance of a dual three-phase integer-slot PM motor with 12-poles is investigated. The advantages of using multiphase approach are also clarified in detailed. The integer slot PM synchronous motor is analyzed by both 2D and 3D finite element (FE) methods and in-depth comparison between the results is accomplished. A prototype motor has been manufactured and performance tests are performed. The motor performance results of both 2D and 3D FE analyses are compared with experimental results in order to validate the models. Good agreement between the test and FEA results is obtained.