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January, 1917 gers, and as the motors would be installed on deck where explosive gases might be present, this condi- tion would be dangerous; consequently it was decided to use the ordinary squirrel-cage type. This motor, how- ever, does not have torque sufficient to start a pump against full line pres- sure, and it was necessary to install a bypass on the cargo pumps. Pumps are brought up to full speed with the bypass open, which is gradually closed, at the same time opening up the valve in the discharge line. As already stated, there are 22 of these cargo pumps, and each is equipped with a motor of the following rating: Forty- horsepower, 600 revolutions per min- ute, 3-phase, 60-cyclé, 220-volt, hori- zontal, squirrel-cage of the open type construction. The motors are enclosed in a water- tight casing, as stated above, and this was made of cast iron. When loaded it is necessary for the motors to have proper ventilation, and the enclosing case is equipped with several hand- hole covers, which are opened when the motor is in service. ordered for the next installation are exactly the same, except they are en- closed and no additional water-tight casing will be required. One of the novel features in con- ‘nection with this installation, and which is part of the switchboard, is the method of starting the cargo pumps. Ordinarily the practice is to use a starting compensator with each Ss b Ee dl = a. is pris 15 meses (fs seem iti a Nl ELEVATION H FIG. 7 — GENERAL ARRANGEMENT OF CARGO PUMP The motors THE MARINE REVIEW 11 Table I : Voyage No. 7 of La Brea Compared With Voyage No. 6 of Los Angeles La Brea Los Angeles July lto July 29 to Aug. A : Per cent greater. Percentage less or greater fuel used steaming Percentage less or greater fuel used in port Percentage less or greater time in port discharging Percentage less or greater fuel per knot steaming Percentage less or greater fuel per knot steaming and in port 73.80 81.50 21.13 21.84 Percentage greater or less barrels pumped per hour *36 days, 16 hrs., 50 min. +37 days, 5 hrs., 6 min. squirrel-cage motor. For various reasons it was not considered advis- able to use any starting devices where the circuit would be made or broken on the upper deck, on account of possible presence of explosive gases, and a scheme was worked out by which all the motors were started from the engine room switchboard. Arrangements were also made to start all motors from two compen- sators, one of which is a spare. This is accomplished as follows: The three panels controling the cargo pump mo- tors have running and starting buses, the running bus energized direct from the generators, and the starting bus through the compensators. The start- ing bus is not energized until the contactor at bottom of panel No. 4 is closed. The switches starting the motors are triple pole, double throw. The upper contacts are connected to the starting bus and the lower con- tacts to the running bus. When the switch is thrown into the upper posi- tion, the blades engage the contacts, but no power is available until the switch is pushed all the way in, which closes a small auxiliary contact, which in turn closes the main contactor on bottom of panel No. 4. This in turn energizes the starting bus through the compensators, and the mo- tors start. An ammeter is installed in the starting circuit, which indicates when the motor is up to speed. When the motor is ‘up to speed the motor switch is thrown into the lower posi- tion—that is, on the running bus— and the motor is then operating on full voltage. When throwing the mo- tor switch from the upper to lower position, the auxiliary contact is the first to open, which in turn opens the main contactor, with the result that the making and breaking of the starting current is made on the main contactor. Each motor circuit is sup- plied with three fuses, installed on a rack back of the switchboard to protect the motors from overload. By referring to voyage seven of La Brea and voyage six of Los ANGELES, Table I, it will be observed that the des- tination in each case was Antofagasta, Chili, and that Los ANGELES preceded La Brea by two days. Notwithstand- ing La Brea had been out of dock a month longer than Los ANGELES and a greater time in warm water, it is stated that she could have overhauled Los ANGELES and discharged first had the contrary not been arranged. ‘The weather conditions were reported as follows: La Brea—July 1 and 2, rough follow- ing sea; July 3 to 7, fine weather; July 8, rough; July 9 to 12, fine weather; July 13 to 22, strong head wind and sea; July 23 to 30, fine weather; August 1 to 9, strong southwest wind and sea. Los ANGELES—June 29 to July 5, fine weather; July 6 to 10, fresh head wind and sea; July 14 to 17, strong head wind and sea; July 18 to 28, fine weather; July 29 to August 7, moderate head wind. It will be noted that La Brea con- sumed 17.09 per cent less fuel steaming, 42.47 per cent less fuel in port, 44.92 per cent less time in discharging, 17.43 per cent less fuel per knot steaming, 17.92 per cent less fuel per knot steaming and in port, and discharged 83.65 per cent more barrels of oil per hour.