Prototype tests of outer-rotor-type high-speed pm motor

Many kinds of servers for communication base stations are being installed to provide information technology (IT) services. Hence, the servers require not only high-performance processer but also their cooling system. Among the cooling systems, a cooling fan is the most suitable due to good balance between performance and cost. Nowadays, the cooling fans are required to be improved the cooling performance and efficiency because the heat generation in servers is increased. In a previous paper, several cooling fan motors are designed and compared each other. As a result, an interior permanent magnet (IPM) motor with the magnets equally divided in the circumference direction has the highest efficiency. This paper presents prototype test results of the proposed IPM motor, which are compared to the calculation results. Next, stray losses caused by eddy current and harmonic current are investigated by using three-dimensional finite element method (3D-FEM).