The characteristics of the temperature rise of the marine A.C. generator shall be obviously to settle the over current protective device for the generator or to get the fluctuation of the temperature rise of the generator applied on random variable loads, such as winches, cranes and so on. Though the temperature rises of electric machines generally have been represented by the single time constant, the result of the analysis on the marine A.C. generator indicates that the armature winding's and core's temperature rise is due to two time constants which are obtained easily from the actual load tests on shop. The armature winding is heated by copper loss in the winding itself and iron loss in the armature core. As the armature windings are covered by the materials which are electric and heat insulations, the temperature rise in the armature winding is more than in any other parts of the generator. This temperature rise make effect of electric insulation of the armature winding reduce and shortens the life of generator. In this paper, the equation calculating the temperature rise of the armature winding and core is explained in comparison with the actual generator's test results. The equation for the temperature rise of the armature winding is led from the block diagram showing the heat flow in the armature winding and core. The coefficients and time constants in this equation are obtained from characteristic curves expressing the features of the temperature rise. These characteristic curves are plotted referring to the load test on shop. The approximate equation can be derived from simplying the coefficients and time constants in the equation, and is available for calculation of the temperature rise on generator's over loads. In result of analysis and actual load tests, the temperature rise is determined by two different time constants which are commonly for the armature winding and the core.
As regards the economic analysis of ships, there is always an argument as to the method of analysis to be applied and the data to be inputted. In this paper, the author has tried to give an answer to this problem by presenting a simple and clear-cut method of analysis which is featured by the introduction of optimum conditions for the design and operation of a ship with special emphasis on those of her engine. Results obtained are summarized as follows; (1) There are two optimum points, i.e. profit maximum (Pmax) point and transportation cost minimum (Cmin) point, which are important in designing and operating a ship. (2) Optimum conditions for Pmax and Cmin points of a ship are presented showing that these conditions are influenced by the fuel consumption characteristics of her engine. (3) From the relations which define optimum conditions, the influence of economic factors such as freight rate, fuel price has been shown. (4) By applying the same relations, several problems pertinent to the design and operation of a ship have been discussed.
Since 1972 when the Japanese law for the prevention of marine pollution fully came into force, most large ships with Japanese flags have been provided with a waste oil incinerator and until now many experiences and operating results have been taken. Machinery Plant Committee Group I took up the standard on waste oil incinerators as one of its subjects in 1974, and made out this standard after consideration based on the results of inquiries to five Japanese ship-ping companies and nine Japanese shipyards. This standard consists of“waste oil quantity”, “burning solid waste”, “the burning capacity of waste oil incinerator”, “the rough flow chart of the waste oil burning system”and“the instrumentation and controls of the waste oil burning system”. For reference the results of the following inquiries are mentioned in addition. The trouble with incinerators. The waste oil treating method of ships not provided with incinerators. The incinerators for turbine ships.
So far, many studies have been published on the lateral vibration in marine shaft systems. These studies are, however, mainly on the critical speed of lateral vibration, and there are few total analysis on the responses caused by lateral vibration because evaluation of the factors (propeller exciting force, characteristics of shaft supporting systems, propeller damping, oil film damping of bearing, etc.) that have important effects on the responses is difficult. Today, with the tendency of the high-power shafting system, evaluation of the responses caused by the lateral vibration due to propeller exciting force is going to be required on the shafting design. Thereupon, the authors have made evaluation of the lateral vibration by utilizing the transfer matrix methods to meet the demand of shafting design. But, on the characteristics of propeller in these calculations, there are applied the conventional values.
This paper presents some results of the calculation on the forced response of lateral vibration in the line shafting of twin screw ships. The calculation, by means of the transfer matrix method, takes into account of the mass and stiffness of ship structure, the gyroscopic action of the propeller and the stiffness and damping of oil-film in bearings. In the case of the ships' line shafting, the oil-film stiffness in bearings can approximately be considered as rigid, since the relative deflection between bearing and journal is very small. The oil-film damping, existent as it is, is less than the damping of the propeller. In the case where the ship hull is assumed to be rigid, the orbit of shaft centre is nearly circular, which means considerable whirling. In the case of the bossing-type hull structure, however, the orbit changes to ellipse with very high eccentricity ratio, which means that the vibration is practically unidirectional and that the precessional direction such as forward or backward of orbit may be insignificant. Also, the authors present an approximate calculation method based on the modal analysis for covenient use in primary planning of ship hull and/or line shaft system designers. The resonant response amplitude by this method shows good agreement with the one by the transfer matrix method mentioned above.