ABSTRACT
The design gives details on how the materials are selected, the techniques used, production drawing and the components in electric propulsion drive. The principle of operation of electric propulsion was used and how the electric power voltage (220V) current (5.1A) with power factors (cosФ) 8900.67 was converted to mechanical power output of 0.75KW (1HP) by applying P = V1I1cosФ where P is the output power to drive the shaft to produce effective power of 0.51KW to propel a vessel. The forces, output powers (Ps, PD and calculated; PS is shaft power, PD is the power delivered and PE is the Effective power. Calculated by PD = Ps × ƞS where ƞS is the efficient of the shaft. PE = PD × ƞD. PE is the effective power while the ƞD is the efficient of the propeller. The speed of electric motor (1HP) n is 310 revolutions per minutes while other speeds at a given delivered power were determined by applying propeller law that says PD ∝ n3.The result shows that the voltage varies from 220 – 240V as shaft power a nd effective power ranges from 0.75 – 0.82kw and 0.496 – 0.545kw respectively.
CHAPTER ONE
INTRODUCTION
1.1 Background of the Study
The marine propulsion system is the heart of ship; its reliability directly determines the safe navigation and operating costs of ship (Yan, 2011). The economy, space requirement, efficiency of propulsion and reliability are the most important parameters to the marine propulsion system (Conglin, 2013). Marine propulsion is a mechanism used to move a ship or boat across water. Most modern ships are propelled by mechanical system consisting of motors or engines which are propelled by turning a propeller (Rourke, 2000). A propeller is a type of a fan that transmits power by converting rotational motion into thrust, pressure difference is produced between the forward and rear surfaces of the airfoil-shaped blade, air or water is accelerated behind the blade (Shraddha., 2012).
In electric propulsion system, induction motor is used to drive the marine propeller. The control is affected by ocean surface waves, ocean currents, wind, weather and also ship motion. The speed of induction motor is controlled using flux compactor (Shraddha, 2012).
The use of electric plant has been increasing in recent years, particularly in areas such as deep-water drilling units, shuttle tankers, offshore supply vessels and other ships which require significant power for propulsion service. Today, the energy sector has available mature electric systems which are robust and have high availability (Peter, 2009).
