32 



THE CUBA REVIEW 



SERVICE AND TESTS OF 3-IN. WIRE CABLE 



Wire cable over 2 inches in diameter is 

 unusual, and a 3-inch cal)ie is the largest ever 

 made. The first of this size was made for the 

 Spanish-American IronC().,in 1910, for use in 

 operating an inclined cable railway at Mayari 

 iron mines, where 5()-ton cars are lowered in 

 3-car trains on a maximum grade of 25%. 

 These conditions required a cable having a 

 safe tensile strength of about 150,000 pounds. 

 Each cable is about 7,900 feet long and 

 weighs in the neighborhood of 125,000 

 pounds. The most recent of these cables 

 was installed in March of last year. 



The cables at the Mayari mines pass over 

 drums 20 feet in diameter and are carried 

 along the track on manganese-steel rollers, 

 although wood rollers were first used. The 

 newest of the cables, placed over a year ago, 

 has four laps around the drum; all previous 

 cables had but three laps. 



Service records were kept for the first two 

 3-inch cables installed, designated as No. 2 

 and No. 3 cables; No. 1 cable wasof2-^-in. 

 diameter, and its service was only 1332 

 months. The following tabulation gives the 

 service records of the two 3-inch cables: 



No. 2 No. 3 



Placed in service 1-16-1911 7-3-1912 



Removed 7-1-1912 3-21-1914 



Time in service 173^2 mo. 203^ mo. 



No. trips with oi*e: 



Three-car trips 4 



Two-car trips 10,154 5,966 



One-car trip 2,194 12,488 



Total trips 13,068 17,718 



Total ore cars lowered 23,222 22,992 



Trips with other cars . 408 



Tons of ore lowered. . . 1,144,689 1,104,926 



During the period that the No. 3 cable was 

 in service important changes were made, and 

 owing to the conditions of operation this cable 

 received unusually severe treatment. To 

 minimize slippage the amount of cable lubri- 

 cant was reduced, and as a result the corrosion 

 of inside wires in tlie samples of No. 3 cable 

 was noticably greater than in the samples of 

 No. 2 cable. The total stretch of No. 2 cable 

 was 32 ft. 3 in., or 0.41% of the total cable 

 length of 7,830 feet, and the total stretch 

 of No. 3 cable was 22 feet, or 0.28%, of its 

 length of 7,980 feet. 



Cable No. 3 was made with a 1 1-8-inch 

 wire-rope center composed of six strands of 



19 wires each al)out a hemp center. Around 

 the 1 1-8-inch center wire rope were six 

 strands of 19 wires each. The wires were 

 plow steel, having a tensile strength of about 

 225,000 pounds per square inch; they varied 

 in size from 0.061 inch to 0.225 inch. The 

 steel in the cross section of the cable No. 3 

 was 4.1178 square inches, which gave an 

 assumed tensile strength for the caljle of 

 723,350 pounds. 



Strength of Wor7i Cable. 



The greatest number of broken wires in a 

 length of 6 inches was 40 out of a total of 72 

 outside wires. Theoretically 40 broken wires 

 would reduce the tensile strength of the cable 

 about 30%. In addition to this, the wear 

 somewhat reduced the area of outside wires. 

 Tests of the worn cables showed ultimate 

 strengths of from 47.8% to 70%, of the 

 strength of the new cable. 



Tests on 14-foot sections of cable No. 2 

 gave 582,000 pounds and .594,600 pounds as 

 strengths of used cable and 728,100 pounds 

 as strength of unused cable. Used section 

 of cable No. 3 developed strengths of 216,200 

 pounds, 342,800 pounds, 723,350 pounds 

 (practically uninjured), 719,200 pounds (part 

 of the same specimen as preceding) and 506,- 

 000 pounds. Tests of unused cable gave 

 strengths as follows: Cable No. 2, 728,100 

 pounds; cable No. 3. 723,350 pounds, and the 

 new cable now in use. No. 4, 751,600 pounds. 

 — Engineering News. 



NEW SUGAR CENTRAL 



It is reported that a contract has been made 

 with J. G. White & Co., of New York for a 

 sugar central to be erected at Mefan, Oriente 

 Province, capacity 80,000 bags, to be ready in 

 time for the sugar season of 1917. 



EARNINGS OF THE SANTIAGO ELECTRIC 

 LIGHT AND TRACTION COMPANY 



1915 1914 



May gross $40,463 .$39,867 



May net 20,479 20,169 



First4mos., gross 148,913 148,874 



First 4 mos., net 68,995 73,081 



According to The Havana Post, an inventor, 

 Senor Morales of Holguin, has patented a new 

 cannon in which the French Government has 

 become interested to the extent of offering 

 the inventor .$5,000 for his invention. 



