830 



THE INDIA RUBBER WORLD 



August 1, 1921 



m. SPECIFICATIONS FOE HIGH-TENSION (SECONDARY) IGNITION 



CABLES 



Conductors shall be stranded and covered with rubber in- 

 sulation. 



High-tension (secondary) ignition cables shall be plain rubber 

 covered, single braided, rubber face taped and single braided or 

 double braided. Weatherproof braid shall not be used on this 

 type of cable. 



High-tension (secondary) ignition cable sizes shall be as shown 

 in Table 2. 



VI. SPECIFICATIONS FOR VARNISHED CAKBRIC INSULATION LIGHT- 

 ING AND STARTING CABLES 



Conductors shall be constructed as described in Section V, and 

 shall be stranded as shown in Table 4. Lighting and starting 

 cables of this class shall have two or more layers of overlapping 

 varnished cambric tape. .-Mternate layers shall be laid in opposite 

 directions. Lighting and starting cables of this class may be 

 either single or double braided. 



Table 5. Additional Speofications for Varnished Cambric 

 1nsui..\tion .and .'\rmored Lighting .^nd St.\rtinc Cables 



IV. SPECIFICATIONS FOE LOW-TENSION (PRIMABY) IGNITION CABLES 



Conductors shall be bunched or stranded and covered with 

 rubber insulation. Low-tension (primary) ignition cable shall be 

 plain rubber covered, single braided, rubber face taped and single 

 braided, or double braided. Low-tension (primary) ignition 

 cable sizes shall be as shown in Table 3. 



Table 3. Low-Tension Ignition Cable Sizes 

 NoM. Size, 

 No. Wires in Strand 



Wires ,— ^ ^ Max. Outside 



NoM. Size In Strand A.w.c. In. Diam. In. 



5 mm. 12 26 0.0159 0.207 



(0.197 in.) 19 27 0.0142 



MiN. 



Outside 



Diam. In. 



0.187 



V. SPECIFICATIONS FOR RUBBER-COVXBED LIGHTING AND STARTING 



CABLES 



Conductors of cables Nos. 16 to 10 A.w.g. inclusive shall be 

 either bunched or stranded as desired. Stranded construction is 

 recommended for flexibility. Conductors of cables No. 8 and 

 larger shall be stranded and may be either concentric or rope lay. 



Conductors shall be covered with rubber insulation. 



Note — Lighting and starting cables shall be single braided, rubber face 

 taped and single braided, or double braided. 



Lighting and starting cable sizes shall be as shown in Table 4. 



Conductors shall be constructed as described in Section V and 

 shall be stranded as shown in Table 4. Lighting and starting 

 cables of this class shall have two or more layers of overlapping 

 varnished cambric tape. Alternate layers shall be laid in opposite 

 directions. Lighting and starting cables of this class may be either 

 single or double braided. 



BUREAU OF STANDARDS ANALYZES PNEUMATIC TIRES 

 The Bureau of Standards, Washington, D. C., is carrying on 

 an interesting series of investigations in order to develop a 

 standard specification for pneumatic tires. A tire-testing dyna- 

 mometer has been installed with a view to determine the amount 



Bureau of Standards Tire-Testing Dvnam(imi;ii.k 



of energy dissipated in heat in tires operated under different con- 

 ditions of axle load, inflation pressure, speed in miles per hour, 

 and tractive efifort. By means of this machine the pressure of 

 the tire against the wheel with which it is in contact may be 

 measured. 



In analyzing various brands of autonioliilc tires, the Bureau 

 of Standards makes use of what is scientifically termed an 

 accelerated aging test. During a year, for instance, "the Rubber 

 Section of theiBureau of Standards analyzed for the War De- 

 partment more4than 500 samples of rubber, representing 250,000 

 tires, and having a valuation of $20,000,000." 



As a result of these tests valuable assistance has been ren- 

 dered tn rubber manufacturers, while the quality of rubber com- 

 pounds has been greatly improved. 



