The Birmingham age-herald., 1919-06-01
THE BIRMINGHAM AGE-HERALD SUNDAY, JUNE l, 1919

the power plant. The electric current thus generated is led through copper ca- bles and suitable control appartus to electric motors and it is these motors which actually drive the propellers of the ship. Thus electricity acts as con meeting link between the steam or other motive force and the propellers. The in ternal combustion engine, which is some- what similar to ordinary gasoline engine,
 is also coming into prominence as power for the generation of electricity. This apparatus, whether it be a steam turbine or an oil engine, is called the prime mover.
 The question, What is a steam tur- bine?" may we'll be asked at this point. Conceive an enclosed water wheel with steam playing against the paddles in- stead of water, and you have sim ple elementary idea of what a turbine is and how it operates.
 NO MECHANICAL GEARS
 Next there need be no gears in the electrically driven ship. The function usually performed by gears Ohat is, to make a connection between the turbine which is to be efficient must revolve at a relatively high speed, and the pro- peller which to be also efficient must
 
 electrically, thus permitting both tur- bine and propeller to operate at high efficiency.
 Just as in the automobile it is desir- able to shift gears it is also desirable at times to accomplish the same result CT board ship. though not necessarily for the same reason.
 Electricity lends itself admirably to effecting these changes, whereas no bac Uot n accomplish this mechanically in large ships.
 In addition to this factor. electric drive has appealed especially to naval men from military point of view.
 MILITARY ADVANTAGES The primary military advantages of the electric ship, as recently pointed out by Commander S. NJ. Robinson, U. S. N, rests on the ability to arrange the pro- polling machinery in a number of sepa- rate watertight compartments throughout the ship placed near the center so that they may be protected from damage due to torpedo attack, shell fire, grounding, collision, etc.
 The capability to form new combina- tions of control and operation by the convenient isolation of defective appara- tus, simply by cutting off the electric connections; the low cost of maintenance; the reliability of the equipment and an economical operation at many different speeds are also valuable considerations. Let us now examine these principles in actual practice. The best example to- day is the United States battleship New Mexico, the first capital ship of the navy to be equipped for electric propulsion. She was built at the Brooklyn navy yard and launched in 1917. The electrical pro- pulsion equipment was made and in- stalled by the General Electric company.
 THE NEW MEXICO DESCRIBED The New Mexico weighs 32,00O tons and requires 2S,O0O horse power nearly one horse power for every ton of weight. She is of the oil burning type, with a total oil capacity of 340O tons or 6,S0O, 600 pounds, or about 100000 gallons. The oil burners heat nine steam boilers each of which can deliver 4000 horse , power at pressure of 250 pounds to the square inch. The steam from these boil CTS operates two turbo- generators which constitute the power plant, each capable of producing 14,0O0 horse power. The cur rent generated from the turbines oper- ates four motors-one for each propeller. The motors are F feet in diameter. They are operated from a central switchboard or control station where the engineers on receipt of instructions from the ships 8 bridge can start the ship forward, or backward, run the propellers at different speeds in either direction. They can run all four motors from one turbo-generator or they can run the two port motors from one generator and the two star board motors from the other generator FLEXIBILITY OF CONTROL If one of the propellers breaks down, | by simply dsconnecting the motor circuit, | the power of the two power plants can l be used to opereate the remaining three | propellers. These are only few of the | .arious combinations of control and op eration which form one of the main fea- | lures of the electric ship.
 l Besides utilizing electricity for propul- sion purposes, there are many auxiliary
 uses to which the current can be put on a battleship. Current from the main gen.