This paper presents a small power generation system motivated by a coreless stator AFPM (Axial Flux Permanent Magnet) generator which is driven by the rooftop ventilator. The generator consists of discs for the rotor and the stator geometry. The stator disc is sandwiched between two rotor discs and the magnets in the two opposite rotor discs may be placed N-S arrangements. Since there is no silicon steel inside the coils, we should eliminate the magnetic pulling force between the rotors and the stators. When the ventilator rotates, the flux of the permanent magnet rotors part move across the air gap and induces the emf in the coreless coils. After that, the ac voltage is rectified to dc voltage and finally charged to the 12 V 5 Ahr battery for household appliances. To analyze the magnetic circuit, the finite element analysis was used to simulate the magnetic flux density in the AFPM generator. The test is operated in electrical machines laboratory and essentially to determine the characteristics of prototype generator. Based on the experiments, the results of the output voltage can achieve 103 V with no-load, and 20 V on 100 Ω resistive loads at the speed of 200 rpm. For the results after installing the generator on the roof of a building to charge the 12 V battery, the minimum wind speed for enough charging to battery is at 10 rpm. Furthermore, the prototyped of the generator is relatively small and cheap. After the fabrication and testing of the prototype, this system has been proved feasible for practical application.
 Wind Is Ravine Ventilator CO. Ltd. http://www.0933772983.com.tw/start.htm
 Backward-Curved Fan. http://www.remco.co.uk/products/bcf.asp
 Y. Ting, H. Gunawan, A. Sugondo, K. L. Hsu and J. T. Teng, “Analysis and Design of Roof Turbine Ventilator for Wind Energy Harvest,” Proceedings of the 2nd International Conference on Mechanical and Electronics Engineering (ICMEE), Kyoto Japan, 1-3 August 2010, pp. 265-269.
 I. Daut, C. Shatri, M. Irwanto, A. N. Syafawati and S. S. Shema, “Power Generation Roof Ventilator,” Proceedings of the 2011 International Conference on Environment and Industrial Innovation IPCBEE, Singapore, 2628 February 2011, pp. 183-187.
 S. Dangeam, “An Electric Generator Driven by a Roof Ventilator,” Energy Procedia, Vol. 9, 2011, pp. 147-158. http://dx.doi.org/10.1016/j.egypro.2011.09.016
 J. F. Gieras, “Permanent Magnet Motor Technology: Design and Applications,” 3rd Edition, CRC Press, Boca Raton, 2009. http://dx.doi.org/10.1201/9781420064414
 J. F. Gieras, R. J. Wang and M. J. Kamper, “Axial Flux Permanent Magnet Brushless Machines,” 2nd Edition, Springer, Berlin, 2008. http://dx.doi.org/10.1007/978-1-4020-8227-6
 N. F. Lombard and M. J. Kamper, “Analysis and Performance of an Ironless Stator Axial Flux pm Machine,” IEEE Transactions on Energy Conversion, Vol. 14, No. 4, 1999, pp. 1051-1056. http://dx.doi.org/10.1109/60.815027