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VOX.0ME 74 POWER 18S4--UeOnw>HlU Pnbllittlfic Catnap. loe. ELY C. HUTCHINSON. Editor NOVEMBER 10, 1931 1 PLAINTIFF'S t EXHIBfT NUUBER 19 Fictitious Price Bait Being in the market for the equipment of an extraordinarily important power house, a reputable public utility engaged a profes sional purchasing agent of wide local reputation to do the buying. Competition was desperately keen, so here Was the opportunity, thought the machinery men, to cash in on their assiduously-developed friendship with the purchasing Pooh-Bah. The buyer's representative, sensing the situation, was also anxious to prove to his employer the wisdom of selecting him for such an important work. . So, choosing two competitors for each principal division of the job. the agent told each confidentially of the purity of his desire to befriend him. But, since his price was high, the best that could be s done was to offer half the units at the other fellow's lower figure, which he then pretended to name. Thus each of the selected bidders -I . -..'V was used in an attempt to force a competitor to accept a fictitious at-'' price for his product. When the scheme was discovered the purchasing agent blandly called off the deal and announced he was ready to receive "final" prices from all. And that purchasing agent occupies an important place in the business of his community today. New Control Cables Have Improved Characteristics By H. M. FRIEND Developments made in insulated wire and cable based on recent discoveries by rubber chemists and physicists and the experimental research work of the cable manufacturers in applying these discoveries TITHIN' the iast two years important improvel ments have been made in control cable. These may be classified as improvements in insulating materials; improvements in protective coverings; and new specifications. Insulating materials used for con trol cable are rubber, asbestos, and combinations of varnished cambric and asbestos. Of these rubber is the most generally used. Rubber-Ixsulated Control Cable When conditions are not severe, such as when high temperatures, chemical fumes, or fire hazards are not present and when the control cable is installed in a conduit system, rubber-insulated cable is satisfactory. When moisture is a serious factor in a conduit system, rubber is the most suitable insulating material. Before discussing the improvements that have been made recently in rubber insulating compounds it is neces sary to mention the two most important discoveries in rubber chemistry made in recent vears. One of these is the use of organic accelerators in place of those of the inorganic types, such as litharge and magnesia, which had been universally employed since the days of Good- vear. By the aid of these new organic accelerator' vulcanization may be accomplished at a lower tempera ture and in a shorter time. Besides lowering the co-: of manufacture the resulting product has better physiem and aging properties. The other discovers' is the use of anti-oxidants that greatly improve the aging qualities of the rubber com pound. These antioxidants were developed by the rub ber chemists working on the accepted theory that tim deterioration of rubber with time is due chiefly to oxida tion. While there have been numerous other development- in rubber chemistry in recent years, these two grcai discoveries are recognized as the most important sinci the work of Goodyear. Thev are now in general n-- in the rubber industry and have added materially to m life of rubber products. Recently cable manufacturers have devoted a con-" enable amount of work to adapting these discoveries v- rubber chemistry to their rubber insulating compound- for cable. On account of the many characteristics oi tn< compound which can be changed by varying the "r gredients added to the rubber, more interest has beer aroused in rubber-insulated cable during the last t'v,` years than in any recent period of equal length. _ This research work bv the cable manufacturers n-' produced rubber insulating compounds in which tn inherent weaknesses of rubber, such as, aging with turn rapid aging with heat; deterioration by oils, acids aw is M! I f*r-' v* - *> ^. *5^ -.* V ."*>" S -r t '? f-r C-;~: % :e u- -Sjy, :e e:TV- 'ill lev** m as Jr**? le id aikalies; and injury bv ozone, which is formed'when corona is present, - have been largely overcome. As control systems operate at voltages of 250 or less, coronaresisting compounds need not be discussed here. Xhe problem of reducing the inherent tendency of rubber to deteriorate with age has been studied for a long time. As applied to rubber-insulated cable this subject was attacked by one cable manufacturer some vears ago before the recent discoveries in rubber chem istry by developing an insulating material that has the characteristics of a rubber compound but is softer and of lower mechanical strength than the standard rubber compounds. The composition of this insulation has been kept secret, but it is. understood to consist of an oil-base compound with only a small.amount of rubber added for mechanical strength. Therefore the properties of the compound do not depend on the characteristics of rubbeT. and it has superior aging qualities, resistance to the deteriorating effects of heat, oils, acids and alkilies as well as being iess affected by corona. However, the physical properties and insulation resistance are lower than those of the standard 30 per cent rubber insulations, or the recent improved types. In two articles on control cable in Power, Nov. 19, 1929, page 796, and Dec. 3, 1929, page 881, the writer various percentages of rubber with the new organic accel erators and anti-oxidants added to give superior qualities. In physical and electrical characteristics they meet the requirements of the standard specifications for 30 per cent rubber insulation with the exception of the chemical analysis, which they will not pass because of the presence of the organic accelerators and anti-oxidants. To check the improvements in the aging character istics of rubber compounds the rubber chemists have developed new tests for measuring die aging under accelerated conditions. This is necessary because to do so under service conditions would require too long. These tests depend on exposure to oxygen, usually at tem perature and pressure higher than normal atmospheric. Two of these tests are rapidly coming into general use. the Bierer-Davis oxygen bomb test and the Geer test. In the Bierer-Davis test the samples are heated to 70 deg. C. in oxygen under a pressure of 300 lb. per square inch. This test is quicker and more nearly dupli cates natural aging than the other. In the Geer test the samples are heated in a current of air maintained at 70 deg. C. for 96 hr. After the samples have been subjected to these tests their physical properties are measured. The depreciation in tensile strength and elongation must not exceed certain limits. Leading specifications now include or are being revised to include accelerated aging tests made by the Geer dry-heat and the Bierer-Davis oxygen-bomb methods. As an illustration of the improvement in the aging properties of these new rubber compounds data are given from an address delivered by Charles R. Boggs. May 13. 1931, before the Signal Section of the American Railway Association. A rubber compound conforming to the specifications of this section is given in Table I. Table II and Fig. 2 give the results of tests made on shelf-aged rubber insulation and Table III and Fig. 3 give the results of Bierer-Davis bomb tests made to deter mine the effects of aging on bare-rubber-insulated wire at room temperature in the diffused light in Mr. Boggs' Fig. 1--Section of multi-conductor robber-insulated control cable that may be laid directly In the ground stated "At the present time the question of the most suitable rubber compound for insulated wire has not been settled. The fact that leading cable companies have recently developed new compounds possessing resistance qualities to ozone, heat and aging superior to the 30 and 40 per cent rubber compounds shows that there is a trend away from the old standard." This development work on the part of the cable manu facturers and their application of the discoveries in rubber chemistry have resulted in great improvements in rubber insulation for cables. Some of these earlier developments gave compounds which, though possessing superior aging qualities and resistance to corona, were as inferior in physical properties as they were soft and mushy. Further research work, however, has improved these properties, with the result that rubber insulation is now available which has superior aging qualities, does not deteriorate rapidly with heat, is less affected by oils, acids and alkalies and has great resistance to the effects of corona; as well as possessing high tensile strength, elasticity, toughness, density (impervious to moisture) and the electrical characteristics required of the stand ard high-grade rubber compounds. These new insulating compounds consist, in general, of TABLE I--RUBBER COMPOUND CONFORMING TO THE SPECIFI CATIONS OF THE AMERICAN RAILWAY ASSOCIATION'S SIGNAL SECTION Percentage by Weight Up-riTer. fine,dry Para rubber..................................................... whiting................................................................................................ Zino oxide...................................................... Litharge............................................................................................... Paraffin and oaokehta..................................................................... Sulphur................................................................................................. 32 23 36 5 2 2 Total................................................................................................. 100 TABLE n --TEST RESULTS OBTAINED WITH SHELF-AGED RUBBER INSULATION Age in Yean . Compound Ai-------------- . Tenaile Elongation, Strength, Inchee; 2-In. Lb.perSq.In. Sample to Break ------------Compound BJ--------------. Tenaile Elongation, Strength. Inchee; 2-in. Lb. per Sq.ln. Sample to Break 1 1,312 n.oo 1,770 11.51 1 690 9.62 1,766 11.10 2 647 7.96 1.662 10.59 3 769 6.55 . 1.641 10.49 4 702 5.37 iCompound A coaforma to the specification* of the "c"*1 section of the Ameri cas Railway Aaeodation, Table 1. lCompound B eame ae A plus organic accelerator and anti-oxidant. TABLE III -- TEST RESULTS OBTAINED ON RUBBER INSULATION AFTER ACCELERATED AGING IN OXYGEN AT 300 LB. PER 8Q.IN. PRESSURE AND 70 DEG. C. Hour* Heated Compound Ai-------------- . Compound B* -. Tenaile Elongation- Tensile Elongation. Strength, Inchee; 2-In. Strength. Inches: 2-In. Lb.perSq.In. Sample to Break Lb.perSq.In. Sample to Break 46 464 6.41 96 Brittle ____ 1.430 1,204 10.44 10.29 Compounda A and B are the eame as in Table II. tezrotL i i i ! ! ii : i "Kg 2DC0 CiX1Ji"`rZii&oimcf S ! l-ttoo lsVe strength ' . 1' | Lywo r 1400 sjr L200 ; two ! 800 !1 ii 600 i 4C0 i1 ! \ 11 !' || i [ i ji [i'illll Hi 'S J1 FT i 11 Age in Years Fit;. 2--Reunite of test obtained with sbelf-sfed robber imoLatioo Compounds A and B are the same as in Tables II and 111 testing laboratory. The physical results reported are average figures for a number of samples. Mr. Boggs, commenting on the tests, said that com parison of the physical properties of compounds A and B, whether judged by shelf aging or by accelerated aging, shows the wonderful improvement obtained by the addition of an anti-oxidant and accelerator to the compound that the manufacturer is now required to use. In general all-asbestos insulated cable should be con fined to open work. It may be used in conduit systems where moisture conditions are not severe, but either the combination varnished-cambric-asbestos type or rubberinsulated cable is better suited to conduit systems. Recent improvements in all-asbestos insulated cabkhave been mainly in the impregnating compounds. A compound is now available that greatly improves tin. moisture-resisting properties of the felted asbesto* and the outer asbestos braided covering. This is a biaci. compound which is both flame- and moisture-proof Where white braids are required the finishing compoundare flame-proof only. Research is being conducted or these impregnating compounds and improvements ar-, soon expected to be available. Multi-Conductor Asbestos-Insulated Control Cable Combination asbestos and varnished-cambric insulation multi-conductor control cable is a recent improved tvp For conduit installation this cable possesses the desirable qualities of asbestos for certain operating conditions and will withstand constant temperatures up to 250 deg. F. It is suitable for conduit installations, as the varnished cambric gives protection from moisture. Where sew: Asbestos-Insulated Control Cable For severe operating conditions where high tempera tures. acid fumes and vapors, oil, grease, or fire hazards are present asbestos insulation is superior to rubber. A standard type of this cable, consisting of a felted asbestos insulation impregnated with special compounds and covered with an asbestos outer braid, also specially impregnated, can be operated under constant exposure to temperatures up to 400 deg. F. For services such as rheostat-grid connections, open wiring in boiler rooms, wiring around chemical soaking pits, and for back-ofswitchboard wiring exposed to high temperatures this type of cable is the most serviceable. The all-asbestos insulated type is made only in single-conductor cable: for multi-conductor control cable a combination of var nished cambric and asbestos is used. Fig. 4--Multi-conduetor type control cable with sbeu>t> and varnished-cambric insulation moisture conditions are present, such as when the cahii is submerged, rubber-insulated cable is better. In the construction of this cable the conductors an stranded tinned copper insulated with a felted-ashcsmwall especially impregnated. Three varnished cambric tapes are applied over the asbestos. A second layer of felted asbestos specially impregnated is then applied Colored-cotton marker braids are woven over each insu lated single conductor. The conductors are cabled with a lay and are then wrapped with a special moisture-pnx" tape which also prevents the outer black finishing com pound from soiling the identifying braids. The oniccovering consists of a heavy woven-asbestos firm impregnated with special black moisture-resisting an-, flame-proof compound which finishes smooth. Anothei manufacturer makes this type of cable with a varnishdcambric jacket replacing the special moisture-proof tape- Flc- 3--Test results on rubber insulation obtained after accelerated using In osyiren at 300 lb. per sq.in. pressure and 70 dec. C. Compounds A and B are the same as in Tables II and III Improvements in Protective Coverings In addition to the improvements in rubber insulatin'1 the cable manufacturers have done considerable "'r to develop better protective coverings for cable and hm' recently put on the market cables with non-menm*sheaths suitable for laying directly in the ground. The-'1 cables were developed mainly to replace the park^A type that was laid in the ground without conduit which depended for its protection on a lead sheath v' galvanized-steel-armor tapes and impregnated .,im coverings. ^ . ]>!( Several manufacturers have modified this type 01 Cl. for control service. These new types are so recem ^ they have not yet been extensively used in contro ,ems. but they possess characteristics which make them <;!oerior for certain services and they allow the design of a control system where the control cable is laid directly in the ground without conduit. This type also offers another choice for use in a conduit system in place of t.he conventional types of lead-sheathed or weather-proofhraided cable. Difference of opinion among engineers regarding the relative advantages of lead-sheathed and weather-proof-braided cable in conduit systems may lead manv installations to adopt the new type with noninetallic sheath as it offers better protection than the weather-proof-braided type without the disadvantages of lead. Several manufacturers have put on the market cables of this type. While differing in construction details, ihev all depend on moisture-resistant rubber compounds and non-metallic protective coverings. The conductors for this new type of cable made by one manufacturer saturant and covered with a seal of the asbestos base calking material is next applied. Two wraps of krai: armor tape are wrapped in opposite directions, making a wall at least 0.060 in. thick. A layer of the asbestos-basv calk is placed over this armor to provide a moisture-pro? ' seal. An outer covering consists of pre-saturated asphaltum-filled jute finished with special impregnating compounds and dusted with soapstone. When this cable is to be used in conduit, where it is unnecessary to pro vide so much mechanical protection, the outer covering is simplified. The protective properties of this cable depend mainly on the calking material, the asbestos braided covering, and the protecting kraft armor tapes. The calking material was developed by research. It is claimed that it is impervious to moisture and the attack of earth acids and earth alkalies, and that it is practically men and remains in a plastic state even at freezing tempera tures. The asbestos sheath filled with the calking mate rial takes the place of the usual lead sheath. It is claimed to be unaffected by electrolysis and is not subject to induced-current sheath losses, is not subject to crystalliza tion and other defects inherent in lead. The kraft armor tapes which are saturated are claimed to be impervious to decay or oxidation. This article has not attempted to cover all the im provements in rubber insulating compounds which have been made, but has merely touched on the most important ones. The next few years will undoubtedly show addi tional improvements in control cable insulation and con struction. The author wishes to thank the Rockbestos Products Corporation, New Haven. Conn.: and the General Cable Corporation, New York City, for their assistance in the preparation of this article. Controlling the Akron Fie. 5--Over 12.000 ft. of asbeBtos insulated wire was used to connect the control of this rheostat to the resistance grids are soft tinned copper. The insulation consists of intermediate-grade rubber that has good aging qualities and a thickness in accordance with A.I.E.E. specifica tions. A colored cotton braid for identification is placed over each insulated single conductor and coated with a clear moisture-proof finish. The individual conductors are cabled with a lay. and paraffined jute is used to round out the cable. Where conductors are numerous and consist of a core and outer layers a single-faced rubberized-cloth tape is applied over the core portion and over each subsequent layer. To protect the colors in the outer layer of conductors a single-faced rubberized-cloth tape is wrapped over each of these conductors. The valleys between individual conductors of the outer layer are filled with an asbestos-base calk that provides a seal over the entire surface of the assembly. An asbestos-braid sheath to in., depending on the diameter of the cable thoroughly impregnated with a This diminutive Westingbouse switchboard on the navy airship Akron, 42 in. wide, 35 In. high and 12 in. deep, with its 2,170 ft. of wire, controls all the power and lighting circuits of the ship. It weighs only 200 pounds f.r.'',