Standpoint Of Economy Research Articles

Mechanical Features Affecting the Reliable and Economical Operation of Hydroelectric Plants

Abstract This paper deals with the subjects of flashboards, trashracks, rack rakes, sluice gates, headgates, penstock valves, air vents, and discharge-measuring devices, from the standpoint of economy and reliability of operation, based almost entirely on the New England Power Company’s practice. It stresses the importance of reducing head losses and leakage and adhering to strength and simplicity in the design of hydraulic equipment.

Temperature limits in large machines

The prevent Institute standards allow a maximum limit of 105 (leg. for fibrous insulation and 125 deg. for mica insulation with an allowance of 150 deg. subject to special guarantees of the manufacturer. In high-voltage machines of large size, the effect of actual copper temperatures higher than 105 deg. may cause softening and disappearance of binding materials, bulging of insulation, and consequent powdering of insulation under periodic pounding of copper on softened material, and, ionization at voids so created. Operating experience of four large size machines demonstrated the above effects to repeatedly take place in machines operating at copper temperatures of 150 deg. cent. None of these effects were noted in machines operating at copper temperatures of 105 deg. cent. or under. Two machines have safely operated for over three years at maximum copper temperatures of 130 deg. cent. Incorrect conclusions may be made as regards the safe temperature limits by judging the performance of machines unless actual copper temperatures are known. Lower ambient temperatures and fractional loads may reduce the operating temperatures 25 to 35 deg. below the assumed limits. Machines designed for high temperatures are less efficient than machines designed for cool temperatures, in one instance the difference being as great as several hundred kilowatts at all loads. The calculation of ventilation of large machines is relatively uncertain; it is of importance to aim at a conservative limit rather than set it too near the danger point. From the standpoint of economy as well as greater safety, it appears that large machines should not be operated at higher copper temperatures than 105 deg. cent. This means that with outside air ventilation seldom exceeding 20 deg., the maximum standard limit with the standard reference of 40 deg. ambient should be 125 deg. equivalent to 85 deg. maximum rise at the copper. In all cases where the room air is close to 40 deg. the maximum copper rise should be limited to 65 deg. Other correlated and important features discussed incidentally in the paper are the typical proportionality of life at different temperatures for fibrous insulation, and the new tentative conventional allowance for reducing to maximum copper temperature, readings taken outside the insulation.

Electric Power Application to Passenger and Freight Elevators

This Committee has been requested to report on the application of electric power to passenger and freight elevators. An enormous amount of electric energy is used for the operation of elevators and it is therefore fitting that the problem be studied from a power economy standpoint as well as from the more important standpoint of protection to life and limb. It is assumed that the reader knows little of this subject and that practically nothing up-to-date has been published. It is not believed that the reader will be particularly interested in accurate technical details, but that he will want to know the range of application of elevators, their motors, controllers and all safety appliances as represented by best present practise. Included in this report are six chapters as follows: I. History and service requirements. II. Types of elevator machines and the limitation of each. III. Charateristics and limitations of d-c. and a-c. motors. IV. Elevator controllers. V. Brakes and other safety accessories. VI. Power consumption.

Marketing as a Problem for Farm Demonstrators

Clearly marketing is one of the most difficult problems confronting the farmer. It will continue to be difficult for years to come, and in all probability will never be entirely settled. One explanation of the difficulty is the fact of the human relationships involved. When any worker on the production side of agriculture goes out to fight for humanity against the leaf hoppers or the San Jose scale, he is cheered on the occasion of every success and encouraged in every effort. All society is against the San Jose scale. In the marketing world the offenders are human beings, with the same rights as the rest of us. It may happen that the supposed offenders are as efficient and honest as the people who criticize them. Even so, the system in which they are involved may need change. It may be imperative that a change be made, and the very fact of a change may hurt certain individuals. These individuals and their friends will not welcome the innovation. During these times of high prices the middleman comes in for a new scrutiny. His margins are the subject of suspicion. The justifica tion of his very existence in the capacity of a merchant is questioned. The concern of those interested in marketing is whether the market ing machinery is reasonably well adapted to the work it has to do, and the manner in which it operates. We might take up much time with the history of marketing, but it will be necessary to pass over this very interesting phase of the sub ject with a few words. The marketing problem is new because it is but a relatively short time back to the self-sufficing farm and the neighborhood when farm produce, with few exceptions, was able to make its way into the national and world markets. For years after farmers were producing for the great markets they were completely out of touch with the forces governing such markets. Following the Civil War the center of production moved toward the west more rapidly than the center of population. Within a few years production outgrew its markets. Corn was worth five to twenty cents a bushel, oats about the same, and wheat fell below a half dollar locally in many districts. Transportation systems were new and badly planned from the standpoint of economy, with the result that 194

The Problems of Interior Illumination

The practise of illuminating engineering as a separate profession is a recent development of applied science. So short a time ago as 15 years there was little if any room or need for such work, and the “art of illumination” was largely a matter of guess work, precedent, and simple attempts to produce artificial light with little attention given to its distribution from the standpoint of economy as that word is understood today.

The problems of interior illumination

The practise of illuminating engineering as a separate profession is a recent development of applied science. So short a time ago as 15 years there was little if any room or need for such work, and the “art of illumination” was largely a matter of guess work, precedent, and simple attempts to produce artificial light with little attention given to its distribution from the standpoint of economy as that word is understood today.