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amperes, 250 volts, at full load. They are separately excited from a 120-volt exciter. There are two ex- citers, driven by the main engines through extension; of main gener- ator shafts. They are of the open, direct current, constant voltage, com- pound wound type, and are self-ex- cited. They each develop 25 kilo- watts at 120 volts and supply excita- tion for the propelling motor as well as the main generators and also pro- vide current for the vessel’s lighting. Only one exciter is on at a time. The main propelling motor is di- rect connected to the propeller shaft through a Timken roller’ bearing thrust block. There is a minimum length of shafting as the propelling motor is located aft. It is an open, direct current, shunt wound, double armature motor, separately excited at 120 volts. Each armature devei- ops 400 brake horsepower at 1285 amperes, 250 volts, and 250 revolu- tions per minute. This motor, which is also supplied by General Electric Co., is of specially rugged construc- tion to withstand the shock of sudden stopping due to the propeller strik- ing ice or driftwood. It has two separate field frames. Hither arma- ture can be disconnected from the propulsion circuit in case of emer- gency. Auxiliary Equipment Each vessel is provided with a mo- tor generator so that direct current for lighting and power may be avail- able by running the machine with al- ternating current from shore. It is Single screw, diesel electric, harbor cutter Calumet, for the Coast Guard a squirrel cage, 3-phase, 60-cycle, 220/440-volt, 1800 revolutions per minute, 25 horsepower motor. The at- tached direct current generator de- livers 15 kilowatts at 120 amperes. One auxiliary, diesel driven gen- erating set is installed on each vessel. The engine is qa 2-cylinder, 5%-inch bore, by 9-inch stroke, 26-horse- power, 600 revolutions per minute, McIntosh & Seymour diesel. The generator made by the General Elec- tric Co., has a capacity of 15 kilo- watts, 125 volts, 120 amperes, and is compound wound. A small oil burning boiler is in- stalled on each vessel to supply steam for the steam heating system. The propellers were made at the navy yard at Philadelphia. There are two Gen- eral Electric refrigerators. The wind- lass is of the hand capstan type, A full line of pumps for various purposes are fitted as follows: one each for fuel oil service and transfer, one for lubricating oil, one fuel vil hand pump, one motor driven sani- tary pump with hydro-pneumatic tank controls, one fresh water pump with hydro-pneumatie tank controls, and one motor driven fire pump. Other auxiliaries include; four maneuvering air bottles; one motor driven air compressor; one motor driven ventilating fan for main mo- tor; three bilge eductors, two of which are in the engine room; one fuel oil purifier; one lubricating oil purifier; three spark arrester silen- cers; two drinking fountains; and one air signal horn with tank com- pressor motor and control. General Electric Reviews Marine Activities In summarizing the activities of the General Electric Co. during 1934, in the review prepared by John Lis- ton, the following interesting refer- ence is made to marine equipment: In connection with the govern- ment naval building program, there were constructed equipments con- sisting of turbine-gear propelling ma- chinery of an advanced design for destroyers, auxiliary turbine gener- ator sets, motors and contrcel for nu- merous auxiliaries, searchlights, radio, ordnance control, switchgear, and miscellaneous apparatus. Diesel electric propelling equip- ments and electric auxiliaries were provided for four United States coast guard harbor cutters, The completion of designs for the use of alternating-current motors to meet practically every navy shipboard requirement made possible the first practical installation of this type on the U. S. S. FARRAGUT. The advantages that the substitu- tion of alternating-current auxiliaries offered over those of the direct-cur- rent type comprise simplified design for the synchronous generators, the squirrel-cage induction motors, and the motor starters and a notable re- duction in the weight of the electric equipment particularly cable which is especially important in marine equipment. The simplicity in design thus secured will tend toward great- er reliability in service and will un- doubtedly effect a reduction in main- tenance expense as compared with that of previous equipments. Before the substitution could be made, however, there were two ma- jor difficulties to be overcome. In the first place, there was the ques- tion of such adjustable-speed appli- cations as the steering gear, the an- chor windlass, and certain kinds of deck machinery which required direct current. Secondly, a certain amount of direct current was essential for searchlights and battery charging equipment. The adoption of electro-hydraulic systems, employing constant speed mctors, solved the first problem, The second was overcome by adding a small direct-current generator to the ship’s turbine generating set. This generator also supplies excitation for the synchronous generators, Motor generator sets give direct current. MARINE REVIEwW—January, 1935 Navigation Methods Giving Formulas and Examples Navigators will be interested in a chart recently published and distri- buted by the United States Hydro- graphic office as a supplement to the North Atlantic pilot chart, 1934. On this chart, 29 different methods of navigation, from 1763 to the present time, are tabulated, listing author, publisher, title and date for each method. Given also are the formulas used, the general descrip- tion of the method with an example common to each method, an analysis of the steps in the solution, the rules for the method and notes on the ad- vantages and disadvantages in each case, No originality is claimed fer this work, it being only a matter of research, The tabulations are entitled Resume of Navigation Methods, by Soule and Collins, copyrighted by the United States Naval institute, Annapolis, Md., and reprinted by permission of the copyright owner, Capt. C. C. Soule, U. S. N., is in command of the U.S. S. New MExIco. 15