http://repository.unn.edu.ng/handle/123456789/177 Wed, 02 Sep 2026 19:06:31 GMT 2026-09-02T19:06:31Z http://repository.unn.edu.ng/handle/123456789/9111 Load Equalization between Two Synchronous Motors Driving a Grinding Mill Onwuka, Ifeanyichukwu K. Large Grinding Mills in the cement and mining industries are conventionally driven by two synchronous motors on opposite sides of a girth gear. Operational experience in these grinding mills shows that due to certain unavoidable inaccuracies in the manufacturing of the girth gear, there is a sustained load pulsation, 180o out of phase in the two motors in every mill revolution. This presents a double problem of wear on the gear teeth due to peak torque loading and motor over heating due to peak stator phase currents. To mitigate this problem, a drive system is presented in which the two synchronous motors are electrically connected through their stator and field windings, and mechanically coupled through the girth gear. Model equations for this system was developed and simulated on the MATLAB/SIMULINK environment. Results obtained shows that in the worst case event of such load pulsations, the torque developed by the two motors remained equal. Also, winding currents in the two motors were observed to be constant without any peaks and dips, thereby overcoming the motor overheating phenomenon. If these motors are connected to the same source as the original three-phase motor from which it was derived, the power capability is found to be the same for both the three- and the six-phase motors. Thesis Mon, 01 Jan 2018 00:00:00 GMT http://repository.unn.edu.ng/handle/123456789/9111 2018-01-01T00:00:00Z http://repository.unn.edu.ng/handle/123456789/9108 Sizing a Standalone Solar Pv for a Rural Community Essien, Essien V. The sizing and implementation of a stand-alone solar PV system deployment in a community is easy to maintain, but the initial cost is high. A stand-alone solar PV system can be a solution to an unstable electricity supply when the sizing is done properly. This work presents the sizing of a stand-alone solar PV system for a rural community as a source of electricity for powering the small community in Kwali Area Council of Abuja – Kilankwa 1. The community consist of 78 households, 9 shops, I clinic, 5 churches, 2 schools and 2 mosques. The power requirement of the community was determined by enumeration of the individual load making up the total load of the community. The energy requirement of the community is 365,262.2W. The analysis shows that in order to supply the required average load in the community, it will require 240 number of solar panels (200W each) at the cost of seventy – five thousand naira only for each, 58 strings of batteries with capacity of 11,273.525 Ah each, at the cost rate of one hundred and ten thousand five hundred naira each, 10 charge controllers (60A each), at the cost rate of forty-two thousand naira each, 10 inverters (5kVA each), at the cost rate of two hundred and seventy thousand naira each, making it a total sum of twenty-six million, eight hundred and thirty-three thousand naira only (N26,833,000), to comfortably power Kilankwa 1 community in Kwali Area Council – Abuja. The analysis presented in this work can be applied to any community having similar load requirement. Thesis Mon, 01 Jan 2018 00:00:00 GMT http://repository.unn.edu.ng/handle/123456789/9108 2018-01-01T00:00:00Z http://repository.unn.edu.ng/handle/123456789/9106 Development of a Hybrid Model for Electric Load Forecasting for Semi-Built Up Area By Ezugwu, Cletus O. Electric load forecast is very vital for the reliable operation of power systems. In order to overcome the limitations of conventional statistical forecast algorithms, this work proposes a Neuro-Arima model for the forecast of electric load in semi-built up areas. The design carried out entailed the integration of an Autoregressive Integrated Moving Average (ARIMA) model with an Artificial Neural Network (ANN) model for the forecast of electric load. The digital model of the Abakpa Enugu Nigeria distribution substation (the case study distribution station) was created and the Neuro – Arima model was implemented using MATLAB/SIMULINK software. The Neuro – Arima model was trained and validated using historic load time series data obtained from the case study distribution substation. Results from simulation carried out showed high accuracy using the model to make hourly, three – hours ahead and weekly load forecasts. The high forecast accuracy is indicated by the high values of coefficients of multiple determinations of 0.9304, 0.9146 and 0.9192 for hourly, three – hours ahead and weekly load forecasts respectively. Comparative evaluation carried out showed that the proposed Neuro – Arima model achieved 60%, 24.83% and 39.40% improvements over the conventional ARIMA forecast model for hourly, three – hours ahead and weekly load forecasts respectively. Thesis Mon, 01 Jan 2018 00:00:00 GMT http://repository.unn.edu.ng/handle/123456789/9106 2018-01-01T00:00:00Z http://repository.unn.edu.ng/handle/123456789/9105 Modelling and Steady State Performance of Dual Winding Induction Motor Alhassan, Bernice O. Dual winding induction motors have aroused quite a lot of interest and controversy over the past years. The question of whether dual winding induction motors have improved performance characteristics over their single winding counterpart has yielded varying answers. In this research work, the equivalent circuit of the dual winding induction motor for steadystate operation is obtained through standard induction motor analysis methods. The equations derived are used to simulate the motor performance in MATLAB/Simulink environment and comparison is made between the dual winding induction motor and an equivalent single winding induction motor. The simulation results are presented and discussed. The results of the study show that the dual winding induction motor has a higher starting current than that of the single winding equivalent which is unattractive considering that high starting current is one of the drawbacks of the conventional motors. The high starting current is however responsible for the rather impressive starting torque in the dual winding induction motor which is desired. The starting and maximum torque of the dual winding motor are 18.4Nm and 36Nm respectively which is an improvement over those of the single winding motor (3.2Nm and 12.1Nm respectively). There is a marked improvement in other performance characteristics of the motor under study. The power factor is at 0.9 compared to 0.7 of the single winding motor and the efficiency of the motor also improved from 78% for the single winding motor to 88% of the dual winding induction motor. This shows a 12.8% improvement in motor efficiency, and translates to reduction in energy demand by this motor Thesis Mon, 01 Jan 2018 00:00:00 GMT http://repository.unn.edu.ng/handle/123456789/9105 2018-01-01T00:00:00Z