IEEE 750.1

Description / Abstract: Material comprising this report is directed primarily at the attainment of improved application technique—the attainment of the highest possible quality of performance from a combination of particular devices to perform a given function. The performance qualities exhibited by a composite system composed of numerous devices will be influenced by the character of devices which are selected to work together and the manner in which they are interconnected or correlated. The extent to which such composite systems may be benefited by proper application technique is great.

Realization of the stated objective involves comprehensive treatment of the following character expressed quantitatively in simple compact form.

a. An explanation of the fundamental electrical problems involved.

b. Typical characteristic performance data of the various elements and devices of which the system is composed, which shall define inherent limitations as well as meritorious qualities.

c. Methods of analysis or test by which the qualities and limitations of a particular composite system may be evaluated.

d. Formulation of particular application practices which experience and judgment confirm as assuring good performance.

e. Formulation of a general analysis procedure outlining the various factors which must be examined or checked.

Although this report will refrain from defining or dictating specific characteristics of particular devices, it is quite possible that desirable features brought out by application considerations may assist other groups in creating new devices or improving existing ones.

Electrical applications in aircraft assume many peculiar aspects. Weight and space are of great importance, and reductions in these quantities deserve infinitely greater consideration in equipment for land service. Equipment must be capable of successful operation in the presence of wide variations in ambient temperature, humidity, and altitude. In general, equipment must be capable of withstanding severe vibration in the member which supports it and it may be subjected to intense acoustic energy. Apart from these considerations which are peculiar to aircraft service, all knowledge accumulated through years of industrial experience should be used to the fullest advantage in bettering the performance of aircraft electric systems.

Aircraft electric systems have grown over the years from the early nonessential automobile-type systems to the present-day general-purpose systems which perform many vital functions. Installed capacities have grown also, to an extent that more attention to system protection is necessary for safety. This has occurred during a period when the electrical divisions of the aircraft manufacturers have been expanding in size. In fact, much of the engineering expansion has resulted from the increased dependence upon the aircraft electric system and the consequent growth in system size and complexity. In view of the influx of new engineering talent into these organizations it is apparent that immense benefits can result from a comprehensive summary of good application principles which are founded on sound engineering fundamentals. The unprecedented expansion of size and number of aircraft with ever-increasing electric systems which has occurred since 1941, principally for military service, has resulted in the accumulation of much knowledge and experience relative to good electrical application practice. It is important that this vast reservoir of knowledge be tapped, coordinated, and compiled in the form of a permanent record.

In the final analysis, the resulting benefits will be measurable in terms of:

a. Improved reliability; fewer outages, less maintenanc

b. Lighter weight

c. Simplification of installation, operation, maintenance

d. Greater safety to personnel, airplane, electric equipment

e. Lower monetary cost of aircraft electric service

f. Better quality of electric service, such as voltage and frequency regulation.