Browsing by Author "Mark Nwohu"

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    Determination of the Wire size of a Three phase Squirrel cage Induction Motor with a Missing Nameplate
    (The Nigerian Journal of Engineering and Applied Sciences (NJEAS), 2014-06-29) Enesi Asizehi Yahaya; Mark Nwohu; Ayo Imoru; Tola Omokhafe; Ambafi .G. James
    An empty stator of a squirrel cage induction motor rated at 220/380V, 50Hz with a missing nameplate and without winding has been lying down in a factory for so long and now the factory wants to use it for production purposes. This is a motor whose class protection degree is IP44, IP54 or IP55. This paper presents a method of determining the wire size (diameter) required to rewind the motor to its full rating power capacity. With motor nameplate and using National Electrical Code (NEC) and National Manufacturers Association (NEMA) specifications, the diameter of the wire can be determined. In the absence of the nameplate and the windings, the motor is difficult to rewind in order to obtain its desired characteristics. This can be achieved by the measurement of main dimensions of motor stator, using standard rating specifications, standard performance curves and analytical method.
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    Harmonic Reduction Using Fractional Pitch Winding
    (3rd Biennial Engineering Conference, Federal University of Technology, Minna. Nigeria, 2013-05-16) Enesi Asizehi Yahaya; Mark Nwohu; Henry Ohize; O. Imoru; Usman N. Galadima
    The power source and the nonlinear loads on transmission line are major sources of harmonics and if these harmonics are not controlled, they could lead to heat loss, break down of machines and reducing the efficiency of any machine connected to the supply. The non-sinusoidal currents from the power source increase harmonic contents in the air gap of electrical machines with pole pitch winding which will lead to excessive losses, vibration and noise. This paper presents the use of fractional pitch winding technique for the stator of three phase motor for the purpose of suppressing harmonics. This is investigated between two windings of pole pitch and short-pitch and the results simulated using Emetor Electric Motor software.