Application of the a. c. system for the auxiliaries on the small carge ship

Abstract

It is said that electrification of the auxiliaries on small cargo ship is more usefulthan that of steam drive.The O.S.K steamer “Ondo Maru”(680 gross tons) had installed a main diesel engine=of 600 B.H.P., steam driven auxiliary engines and an oil burning boiler. The fuel consumption was too much and so the next ship of same type“Mihara Maru”had installedthe electric driven auxiliaries of d.c. system, and got good result.These valuable experiences tell us that the electrification is more useful than steam drive, The electrification of the auxiliaries had almost adapted the d.c. system, by the reasonthat the characteristics for winch and windlass are more suitable than a. c. system. Therefore, the a.c. system for auxiliaries of cargo ship has been disregarded.However, it is considered that the a.c. system for the auxiliaries of small cargo shipis worth studing.Now, our company decided to build two small cargo ships of “F”type (about 510gross tons) and I am planning the electrification of the a. c. 230 volts, 60 cycles, 3 phase, for the auxiliaries.Here we call, temporarily, the ship less than 500 gross tons, as the “small cargoship”. The ship of “F”type is installed a main Diesel engine of 550 B.H.P. and followingauxiliares, The generater for the source of these auxiliaries are two sets of 55 k.v.a. which are drived by a Diesel engine respectively.(a) Winches 4 sets of 15 k.w.(b) Windlass 1 _??_(c) Capstan 1 _??_ 2 k.w.(d) Pumps 6 _??_ of 0.75 to 5 k.w. There are other electric installations as follows:(a) Room heaters.(b) Ordinary illuminating lamps and navigating lamps etc.(c) Wireless telegraphy.(d) Radio direction finder.(e) Echo sounding equipment.The electrification of winch, windlass and capstan by the induction motors of polechange wound rotor type, shall have many points of consideration.In this paper, it is concluded that the electrification of the auxiliaries on small cargo ship by a.c. system is rather suitable for quick building of ship, and cheapness ofequipments and easy maintenance of auxiliaries.