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THE WINDER is one of the more important machines in the paper industry. In general, every paper machine has a winder intimately associated with it and there are many others used in the finishing room.

THERE are two distinct types of paper machines to be found in the industry; the Fourdrinier machine, named after its sponsor, and the cylinder machine. These machines with modifications are used in the manufacture of all grades of paper and paperboard.

Static switching control, with its greatly improved reliability, is another step toward automated industrial sytems. A general view of this field including a specific application to a paper mill digester is presented.

Adjustable-speed drives of small and medium horsepower are divided into seven types and the general characteristics of each are described and compared with reference to their application in the paper industry. Mill experience suggests that the flexibility of the adjustable-voltage d-c drive and the simplicity of the wound-rotor drive are satisfactory for most drive applications.

Using motors rated from a fraction of a horsepower up to 3,000 horsepower, the pulp and paper industry is driven largely by electric power. This article gives the method of determining motor requirements for some of the more important applications in this industry.

Three types of wiring systems in common use in the pulp and paper industry are evaluated and compared in terms of such important criteria as reliability, safety, installed cost, adaptability, weight, and installation time.

Chipper drive is one of the most exacting applications to which motors are applied. The size of the motor is determined primarily by the high peak loads which occur intermittently when large logs are fed. Motors for this application must be made mechanically stronger than standard to withstand the shock loads and vibration imposed by the chipper.

Power ties to pulp and paper mills provide standby capacity for the mills, supply them with essential services during protracted shutdowns, and sometimes the tie can operate in reverse to the benefit of the utility. In regions where fuel is available at moderate cost, power ties are limited to carrying a marginal amount of power not available as by-products from process steam passing through mill turbines.

ON THIS and the following 45 pages appear discussions submitted for publication, and approved by the technical committees, on papers presented at the sessions on communication, electric welding, electronics, instruments and measurements, power distribution, selected subjects, and synchronous machinery at the 1937 AIEE winter convention, New York, N. Y., January 25–29. Authors' closures, where they have been submitted, will be found at the end of the discussion on their respective papers. Other discussion of winter convention papers will be published as it is made available.

For many years shellac or synthetic-resin-coated paper has been used in winding condenser bushings. Two years ago work on the development of oil-impregnated-paper condenser bushings was undertaken. When a shortage of shellac was imminent because of the war, effort to complete the development was greatly increased, resulting in its being completed well ahead of the date originally set. Manufacturing processes and impregnating treatments were developed and bushings built and tested. The processes and treatments are described, and the data obtained from tests on representative bushings are given. Complete interchangeability for transformer and circuit-breaker bushings has been obtained for current apparatus designs in the voltage ratings in which the bushings are produced. To a large extent, the new bushings are also interchangeable with bushings of older design in the same voltage rating. The entire insulating portion of the bushing is enclosed in porcelain and metal and this enables the bushing to be held in storage without special provisions for keeping it dry. The oil-impregnated-paper condenser bushings, built for voltage ratings 92 kv to 230 kv, are susceptible to careful control of quality in the processing operations. Exceptionally consistent performance and high dielectric strength are obtained. Consistently low power-factor readings on both hot and cold bushings were obtained. Radio-influence voltage measurements were below proposed standards.

ON THIS and the following 16 pages appear discussions submitted for publication, and approved by the technical committees, on papers presented at the sessions on tensor analysis, synchronous machinery, and protective devices at the 1937 AIEE winter convention, New York, N. Y., January 25–29, and on one paper not presented at an AIEE meeting. Authors' closures, where they have been submitted, will be found at the end of the discussion of their respective papers.

On this and the following 17 pages appear discussions of papers presented at the 1934 A.I.E.E. summer convention, Hot Springs, Va., June 25–29, as follows: (1) one paper presented at the session on electrical machinery (closure); (2) one paper presented at the session on power generation; (3) all papers presented at the session on automatic stations; and (4) all papers presented at the session on insulators. All discussions on the foregoing papers (except that in item No. 1) received in complete and acceptable form at Institute headquarters, and subsequently reviewed and recommended for publication by A.I.E.E. technical committees, are included. Authors' closures, where they have been submitted, will be found at the ends of the discussion on their respective papers.

ON this and the following 33 pages appear discussions submitted for publication, and approved by the technical committees, on papers presented at the sessions on electrophysics, electrical machinery, induction machinery, power transmission, and tensor analysis at the 1937 AIEE winter convention, New York, N. Y., January 25–29. Authors' closures, where they have been submitted, will be found at the end of the discussion on their respective papers. Members anywhere are encouraged to submit written discussion of any paper published in ELECTRICAL ENGINEERING, which discussion will be reviewed by the proper technical committee and considered for possible publication in a subsequent issue. Discussions of papers scheduled for presentation at any AIEE meeting or convention will be closed 2 weeks after presentation. Discussions should be (1) concise; (2) restricted to the subject of the paper or papers under consideration; and (3) typewritten and submitted in triplicate to C. S. Rich, secretary, technical program committee, AIEE headquarters, 33 West 39th Street, New York, N. Y.

On this and the following 18 pages appear discussions submitted for publication and approved by the technical committees on papers presented at the sessions on cables, noise, overhead line problems, and electric welding at the 1935 A.I.E.E. winter convention, New York, N. Y., January 22–25. Other discussions of winter convention papers, and authors' closures, will be published in later issues. The first discussions of winter convention papers appear in Electrical Engineering for March 1935, pages 322–35.

Electrical developments have contributed materially to the efficient operation of pulp and paper mills throughout the United States. This can be appreciated readily when consideration is given to the extensive use of power throughout the industry. In the year 1947, the industry required some 14 billion kilowatt-hours to produce 21 million tons of paper.

Careful analysis of the characteristics of a power system has been found to be necessary before applying Petersen coils to a system which has been operating either with the neutral isolated or grounded. In these two companion papers on Petersen coils, accent has been placed on the analysis of system characteristics in order to determine whether or not the application of Petersen coils will be satisfactory.

THE capital investment in the underground cable system of any large metropolitan utility is so great that any means of increasing its usefulness is of great and immediate interest. The operation of paper-insulated cables at higher copper temperatures than are accepted as normal, offers one obvious means of increasing the usefulness of the cable system where voltage regulation does not limit load.

AUTHORS' abstracts of papers presented at the sessions of the committee on electrical insulation of the National Research Council held in Baltimore, Md., October 11 and 12, 1932, follow. Requests for additional information should be addressed to National Research Council, 29 West 39th Street, New York, N. Y.

THE purpose of this paper is to outline procedures and discuss pertinent problems that arise when restoring service to a metropolitan system following a major shutdown. In the discussion, consideration is given to the fundamental plan of the system, pointing out the inherent features in the design which prevent such failures. Several cases of trouble which have been the cause of service curtailment have been discussed and the service restoration procedure outlined. A brief outline of the essential procedure is given for two types of service restoration.

AN underground high-voltage cable system is made up of two major components: the cable with its joints and accessories and the underground duct and manhole structure. The question of what size of conductor should be chosen ground facilities already exist and when only a few additional feeders are being considered it might seem logical to make use of them. A study of the annual charges may show, however, in some cases, that it will be more economical to for a particular transmission feeder or as a general standard for distribution feeders has confronted every planning group. The voltage for the system is frequently limited to one or to relatively few different values already existing as a system standard, deviations from which would result in increased cost to obtain terminal facilities. Frequently some under-build additional new underground facilities rather than further to congest already existing structures.

THE co-ordination of telephone and power systems has been studied for about 15 years under the auspices of the Joint Subcommittee on Development and Research of the Edison Electric Institute and the Bell Telephone System. Until 1935 the noise frequency studies on distribution systems related chiefly to the types of systems employed in urban and suburban areas.1 Between 1935 and 1937, the work was extended to include rural power and telephone systems, which differ in several respects from the systems employed in urban areas. Measurements of power circuit influence and telephone circuit noise were made on a number of representative rural systems in Nebraska, Iowa, Michigan, Ohio, Indiana, and Virginia, with the co-operation of the operating companies. These tests were supplemented by a theoretical analysis of the problem.

ON THIS and the following 2 pages appear all remaining discussions submitted for publication, and approved by the technical committees, on papers presented at the 1937 AIEE winter convention, New York, N. Y., January 25–29. Discussions of papers presented at the sessions on general power applications, vibration and balance, communication and research, power transmission, education, power generation and electrical machinery, instruments and measurements, insulation co-ordination, and lightning protective equipment at the 1937 AIEE summer convention, Milwaukee, Wis., June 21–25, now are being reviewed by the technical committees, and will appear in ELECTRICAL ENGINEERING as they are released for publication.

Discussion and authors' closure of a paper by J. B. Whitehead and T. B. Jones published on pages 1492–1501 of volume 56, 1937, AIEE TRANSACTIONS (December 1937 issue of ELECTRICAL ENGINEERING) and presented for oral discussion at the cables and research session of the winter convention, New York, N. Y., January 27, 1938.

THIS abstract of a preliminary report gives some results of a study of the life of impregnated paper insulation under way at the School of Engineering, Johns Hopkins University. The work is being supported by the subcommittee on impregnated paper-insulated cable research of the National Electric Light Association. In an earlier work under the same auspices, a study was made of the influence of residual air on dry impregnated-paper insulation. Results of that study (Vol. 47, No. 1 Transactions A. I. E. E., January, 1928) showed the desirability of investigating the effect which different amounts of residual air would have upon the life of impregnated paper insulation. A brief summary of the results so far obtained is given here in the form of eight conclusions, briefly qualified.

THE two criteria of the performance of any system for the delivery of electric energy are, first, its dependability as measured by continuity of service, and second, the quality of the service as measured primarily by the ability of the system to keep the deviations from normal voltage within acceptable limits. The purpose of this paper is to consider the influence of the second of these two factors, namely voltage regulation, on the design and operation of the system.

INTERPRETIVE abstracts of the majority of papers presented at the A.I.E.E. winter convention (January 25–29, 1932) or articles based upon them, were published in the January issue of ELECTRICAL ENGINEERING. Interpretive abstracts of all remaining papers are presented herewith. Members vitally interested and wishing to obtain immediately pamphlet copies of any available papers are requested to use the order form appearing on p. 148 of this issue. In response to popular demand and within its space limitations ELECTRICAL ENGINEERING subsequently may publish certain of these papers, or technical articles based upon them.

A brief survey of the history of paper making in Mexico takes us back to the civilization existing before Cortes. The original races Mayas, Nahoas, Zapotecas, and Tarascas, made sheets of paper from “cactus” and “amacuahuitl.” At the beginning of the conquest, the Spaniards used the paper they brought with them, and later when they needed greater quantities, they installed a small paper mill close to the “Gran Tenoxtitlan.” Later, in the colonial period, the first printing shop in America was installed and during the years 1550 to 1600 the different monastic orders printed more than 100 religous works on paper coming from Spain.

INTERPRETIVE abstracts of all papers definitely scheduled for presentation at the A.I.E.E. summer convention (June 26–30, 1933) are published herewith, excepting only those papers published in this issue of ELECTRICAL ENGINEERING.

INTERPRETIVE abstracts of the majority of papers to be presented at the A.I.E.E. winter convention (January 25–29, 1932) are presented herewith, excepting only those papers published in this issue of ELECTRICAL ENGINEERING and those not available for publication at the closing date of this issue. Abstracts of the remainder of winter convention papers are scheduled for publication in the February issue. Members vitally interested and wishing to obtain immediately pamphlet copies of any available papers are requested to use the order form appearing on p. 70 of this issue. In response to popular demand and within its space limitations ELECTRICAL ENGINEERING subsequently may publish certain of these papers, or technical articles based upon them.

INTERPRETIVE abstracts of all technical papers to be presented at the A.I.E.E. summer convention, June 20–24, 1932, are included herewith, excepting only two papers. One of these is published in full on p. 390–1 of this issue; for the other, manuscript had not been received at the time this issue went to press. Members vitally interested and wishing to obtain pamphlet copies may do so by writing to the A.I.E.E. Order Dept., 33 W. 39th Street, New York, N. Y., stating title, author, and number of paper desired. In response to popular demand and within its space limitations ELECTRICAL ENGINEERING subsequently may publish certain of these papers, or technical articles based upon them.

INTERPRETIVE abstracts of all papers which at the time of this issue are definitely scheduled for presentation at the technical sessions of the winter convention of the American Institute of Electrical Engineers (January 23–27, 1933) are published herewith, excepting only those papers published in this issue of ELECTRICAL ENGINEERING. Abstracts of the remainder of winter convention papers are scheduled for publication in the February issue. In addition to the papers, 4 addresses are scheduled for presentation at the technical sessions.

ON THIS and the following 15 pages appear discussions submitted for publication, and approved by the technical committees, on previously published papers presented at the AIEE winter convention, New York, N. Y., January 24–28, 1938. Authors' closures, where they have been submitted, will be found at the end of the discussion on their respective papers.

INTERPRETIVE abstracts of all papers which at the time of this issue are definitely scheduled for presentation at the A.I.E.E. Pacific Coast convention (Aug. 30-Sept. 2, 1932) are published herewith. In response to popular demand and within its space limitations ELECTRICAL ENGINEERING subsequently may publish certain of these papers, or technical articles based upon them.

On this and the following 2 pages appear all remaining unpublished discussions of technical papers presented at the general session of the AIEE North Eastern District meeting, New Haven, Conn., May 6-8, 1936. Members anywhere are encouraged to submit written discussions of any paper published in ELECTRICAL ENGINEERING, which discussion will be reviewed by the proper technical committee and considered for possible publication in a subsequent issue.

INTERPRETIVE abstracts of all papers presented at the Pacific Coast A. I. E. E. convention (August 25–28, 1931) are presented herewith, only excepting those papers already published in this or preceding issues of Electrical Engineering. Members vitally interested and wishing to obtain immediately pamphlet copies of any of these papers are requested to use the order form appearing on p. 770 of this issue. In response to popular demand and within its space limitations Electrical Engineering subsequently may publish certain of these papers, or technical articles based upon them.

CONSIDERABLE DIFFERENCES of opinion and corresponding differences in practice exist about the safe height for vertical terminations of solid-type paper-insulated cables. The limitations are vacuum formation at the top of well-sealed risers, leads stretching at their base, and moisture effects if the potheads are not hermetically sealed.

A new type of insulation has been developed by the Bell System engineers and put into use for exchange area cables. This insulation consists of a continuous pulp or paper sleeve formed directly on the conductor by a modified paper making process. The manufacture and use of pulp-insulated wire cables involves unique changes in manufacturing equipment, materials and methods, in cable design and installation practises. The development has covered a period of some ten years and is the result of combined manufacturing, engineering, and field studies.

Highly unfavorable operating conditions are often created by the depositing of static charges on teletypewriter paper tape and rolls. This phenomenon of static electrification will cause delays and require the attention of operating personnel. Messages can even be lost as the copy may jam in moving mechanisms and be mutilated. Although radium devices have been employed for a number of years by the Bell System for static control,1 the increasing number of state laws regulating the use of radioactive substances made it desirable to find some suitable substitution. The paper discusses the operating principles and design features of a static eliminator utilizing a high-voltage discharge.

The diversity of equipment used in any finishing room depends upon the types of paper being produced in the mill, and also on the amount of fancy finishing desired. Some mills such as those producing newsprint normally confine their finishing operations to rewinding and splitting defective rolls; others, such as those in the fine paper field, go in for a multitude of finishing or secondary processes which change the visual or physical characteristics of the original paper. These may be something vastly different, but, nevertheless, very important in their relation to the end use of the paper.

THE INVESTIGATION described in this paper was initiated in 1931 by The Rubber Insulated Wire and Cable Section of The National Electrical Manufacturers' Association (NEMA), for the purpose of determining the current-carrying capacities of rubber-insulated wires and cables installed in buildings. The reasons for this investigation were as follows

THE GRAPH-SCOPE is an electronic graph plotter which is designed to provide for the research worker a facility for plotting data which is equal in refinement to those facilities with which he obtains data. In the design of the Graph-Scope four aims have been primary: to provide great flexibility in the finished picture, to reduce the chance for human error, to reduce graph plotting time, and to reduce the eyestrain involved in the usual point plotting on graph paper.

The second largest consumption of d-c power in the United States for electrochemical use is by the chlorine-caustic industry which is expected to have a capacity of about 494,000 kw before the end of this year. Two major types of electrolytic cells — the diaphragm type and the mercury cathode type — are used to produce chlorine and either potassium or sodium hydroxide. Since 1936 most of the conversion equipment installed for supplying these cells has been mercury-arc rectifiers.

Today's large multiplant complexes in the chemical industry not only produce consumer products but also the chemical intermediates necessary to their manufacture. The competitive nature of the industry demands high-quality systems engineering techniques in the design and operation of such a complex. The present extent of these techniques, the nature of the decisions to be made, and the use of computers in their solution are discussed

THE PRINCIPLE of building the larger capacity rectifiers in sectional form was discussed in a paper presented before the Institute at the 1932 winter convention. Obviously, the successful achievement of a sectional rectifier, without its becoming prohibitively large, involved the development of a rectifier section much reduced in size from the familiar conventional rectifier of 500 kw to 1,000 kw capacity. Due to the characteristics of the device, this reduction in size of section inevitably resulted in a corresponding reduction in arc drop with a further enhancing of the advantage of the sectional arrangement. The design was based on a 1,250-amp section, which is approximately the rating above which difficulties due to size begin. The 1932 paper briefly described the first design of sectional rectifier. Since that time, considerable improvement has been made both as to performance and convenience of operation. The present paper describes the 2,000-kw 625-volt unit being installated on the Fulton Street line of the independent subway system of the city of New York for the New York board of transportation. This unit is typical for any capacity above 750 kw at 600 volts. The paper also briefly describes smaller rectifiers for capacities below 750 kw.

In the paper are presented new data on (1) arc-voltage drop and current-limiting effects for arc faults in bar-conductor structures, (2) current-limiting effect of insulated-cable arc faults, (3) cable impedance in an iron conduit, and (4) impedance of low-voltage switchgear circuit assemblies, derived from tests at short-circuit currents in circuits with open-circuit line-to-line voltages of 208-600 volts at 60 cycles. The currents ranged from less than 10,000 amperes to values as high as 100,000 amperes rms in some cases. The new data dispel several illusions with respect to accidental faults in low-voltage bus structures and other low-voltage gear. Contrary to inferences frequently drawn from previously published data, the paper shows that (a). Faults in the typical low-voltage bus structures tested are not self-clearing. (b). Fault arcs do not show the drastic current-limiting effect which they are frequently assumed to exert upon short-circuit currents. Instances are shown where actual fault currents reach 100 per cent of the rms symmetrical values calculated for bolted faults. This study shows a self-clearing tendency for representative types of accidental faults in cable, but it was found that a large current-limiting action prior to current interruption cannot be depended on. The new data, supplementing existing impedance data, definitely indicate the possibility of reasonably accurate calculation of short-circuit currents in low-voltage circuits.

Open wire circuits recently have been developed for transmitting radio broadcast programs with greater naturalness and over greater distances than heretofore (see companion paper ``Wide-Band Open-Wire Program System'' in this issue). The simultaneous utilization of these circuits for the transmission of broadcast programs and carrier telephone messages requires the use of line filters to restrict the program and carrier currents to the proper circuits. The low pass line filter developed for the program circuits and its contribution to the maintenance of good quality in the programs transmitted are described in this paper.

A 220-kv line, 150 miles long has been constructed between Powerton Station near Peoria, Illinois, and Crawford Station in the city of Chicago. This line will probably operate continuously near the static stability limit and will deliver 150,000 kilowatts to the city from Powerton Station near the coal fields of southern Illinois. This line has the highest capacity of any in this area and includes several novel features, such as a unique carrier current system for tripping the breakers at the remote end of the line, for telemetering, load control, and communication. The 180,000-kva transformer bank at Powerton has two 22,000-volt primary windings connected to different busses. The Crawford transformer bank has a 150,000-kva winding at 220-kv, a 75,000-kva winding at 12-kv, and two 90,000-kva windings at 69-kv for connection to separate 66-kv systems. Regulating transformers are provided at both terminals. A 75,000-kva synchronous condenser at the Crawford terminal is connected to the 12-kv transformer winding for voltage control. No 220-kv breakers are used at either end of the line. This paper describes only the operating features and the terminal facilities; a companion paper by Messrs. Oldacre and Wollaston describes the construction features of the line.

This paper summarizes the results of an investigation of the harmonic currents and voltages in the a-c circuits of grid-controlled rectifiers and inverters. The principal part of the paper presents the development of a theoretical method for predetermining the magnitude of the harmonics in terms of the d-c load current, the commutating reactance, the rectifier transformer secondary voltage, and the amount of grid control. Harmonic voltages in the supply circuit may then be calculated from the harmonic currents and the supply-circuit reactances at the various harmonic frequencies. General curves are given to facilitate the calculation of the harmonic currents for the range of conditions usually encountered. In addition, curves are included for the easy determination of the product of the supply-circuit current and its own telephone influence factor, the I.T product, which quantity is useful in inductive co-ordination studies. Comparisons are given between the results of tests and the results of calculations by the theoretical method presented in this paper. These and other comparisons show very satisfactory checks so that the method may be considered to be established. The case of the inverter is treated in a manner similar to that used for the grid-controlled rectifier. The general curves for the rectifier may also be applied to the inverter by appropriate choice of the defining angles. The case of a-c circuits with nonlinear frequency-reactance characteristics is briefly considered, and an empirical modification of the theoretical method is suggested.

This paper is written to present the point of view of the practical operating engineer to whom ``reactive power'' is something that he has to generate and deliver to his customers much as he does ordinary or real power. It happens that this kind of reactive power is the kind which causes the current to lag behind the voltage when it happens to be flowing in the same direction in the circuit as the ``active'' power. However, when it happens to be flowing in the direction opposite to that of the active power (which, in a transmission system is just about as likely to happen), it makes the total current in the circuit appear to lead the voltage and deceives the technician who observes this phenomenon into thinking that a different kind of reactive power (viz., leading reactive power) is flowing in the same direction as the active power. The paper presents an interpretation of such observations in terms of the one kind of reactive power with which the practical operation and control of power systems has to deal and points out the parallelism between active and reactive power in their operating aspects. It also presents an unorthodox metering technique for keeping track of the flow of reactive power in a complicated power transmission network which greatly clarifies and simplifies the problem of dispatching reactive power in such a system; such dispatching being necessary to obtain maximum transmission system capacity and efficiency as well as for system voltage control.