Browsing by Author "Mohammed, O. O"
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Item Field Loss Calculation of a Wind-powered Axial Flux Alternator by Analytical Equations.(Wiley Online Library, 2021-02) Otuoze, A. O; Mohammed, O. O; Ibrahim, O; Emmanuel, A. A; Usman, A. M; Dobi, A. MVarious techniques have been investigated and proposed for core loss minimization in electrical machines. Nevertheless, many of such methods are mostly complicated and not suitable for consideration at a preliminary design stage. In this work, a simplified procedure which uses an analytical approach to minimizing the field’s losses of an Axial Flux Permanent Magnet Alternator (AFPMA), is presented. First, the output equation of an AFPMA is referred, and then the minimization of the losses is investigated by analytical differential equations. The result of the derived-specific magnetic loading is investigated using three different core materials, namely 35RM300, 50JN350, and 65JN800, and is found to reduce with increased frequencies. The 35RM300 core material gives the maximum specific magnetic loading and minimum power loss at investigated frequencies of 50 to 500 Hz. Although the 35RM300 core material gives the best performance, the optimal values are only determined as suitable by the manufacturer’s design criteria. This study is a key indicator for a simple and efficient core material selection in the design of a Wind-Powered AFPMA without the need for complicated analyses at the preliminary design stage.Item Replacement Model for Street Lighting Systems(Faculty of Engineering, University of Nigeria, Nsukka, Nigeria, 2021-01) Usman, A. M; Adediran, Y. A; Otuoze, A. O; Mohammed, O. O; Zakariyya, O. SReplacing failed bulbs of streetlights in a location can be very tasking and expensive if the optimal time for replacement is not determined. In this paper, a model has been developed that helps to establish the optimal time for the replacement of streetlight bulbs. Burnt-out bulbs are replaced individually when they fail, and group replacement is carried out on all bulbs after a specified time. The costs for both individual replacement and group replacement are determined. The developed model was applied to locally sourced data from a field survey of a streetlight installation at the University of Ilorin, Ilorin, North-central Nigeria. The model gave the optimum replacement time of burnt-out bulbs as the eighteenth week when applied to the data used in this work. The optimum replacement time will be dependent on the dataset used. This makes the developed model useful in establishing the optimal replacement time of any stochastically failing items that are in large quantities. The model will help to reduce maintenance costs for facility managers.Item A Review of Smart Grids Deployment Issues in Developing Countries.(Faculty of Engineering, University of Maiduguri, Maiduguri, Nigeria., 2017-12) Otuoze, A. O; Usman, A. M.; Mohammed, O. O; Jimoh, A. ASmart Grids (SGs) have taken a centre stage in achieving a smarter, more reliable, robust, secured, economically efficient and more environmentally friendly mode of power generation and utilisation. Massive deployment is being recorded in developed worlds. While most of these countries are investing heavily in the development of SGs, well-articulated areas of research and development are key aspects with special emphasis on its security since it involves complex interconnection of units and systems which are expensive to install and maintain. In developing nations, especially those of Africa, realisation of adequate power supply to meeting the ever-growing demand has been a mirage with demand on geometric increase and with every increase largely meaning a drift away from the supply. Hence, attention is focused on capacity expansion in most developing nations rather than SGs deployments especially considering the various challenges militating against the development despite the huge advantages. Although, some of these nations have made tremendous achievements in this regard, the associated challenges have become major source of worry for most of the nations. This paper gives highlights of these issues and possible measures of overcoming them in order to enhance sustainable SGs deployments in developing countries like Nigeria.