NATIONAL BUREAU OF STANDARDS REPORT

3621

ISOCMDLE DISTRIBUTION OF

PRE PRO DUCT ION 100- PAR 56 LAMP

FOR LEAD-IN SYSTEMS

by

R. T. Vaughan

R. W. Crouch

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS
U. S. DEPARTMENT OF COMMERCE

Sinclair Weeks, Secretary NATIONAL BUREAU OF STANDARDS

A. V. Astin, Director

THE NATIONAL BUREAU OF STANDARDS

The scope of activities of the National Bureau of Standards is suggested in the following listing of

the divisions and sections engaged in technical work. In general, each section is engaged in specialized research, development, and engineering in the field indicated by its title. A brief description

of the activities, and of the resultant reports and publications, appears on the inside of the back

cover of this report.

Electricity. Resistance and Reactance Measurements. Electrical Instruments. Magnetic

Measurements. Electrochemistry.

Optics and Metrology. Photometry and Colorimetry. Optical Instruments. Photographic

Technology. Length. Engineering Metrology.

Heat and Power. Temperature Measurements. Thermodynamics. Cryogenic Physics. Engines

and Lubrication. Engine Fuels. Cryogenic Engineering.

Atomic and Radiation Physics. Spectroscopy. Radiometry. Mass Spectrometry. Solid State Physics. Electron Physics. Atomic Physics. Neutron Measurements. Infrared Spectros- copy. Nuclear Physics. Radioactivity. X-Ray. Betatron. Nucleonic Instrumentation. Radiological Equipment. Atomic Energy Commission Radiation Instruments Branch.

Chemistry. Organic Coatings. Surface Chemistry. Organic Chemistry. Analytical Chemistry.

Inorganic Chemistry. Electrodeposition. Gas Chemistry. Physical Chemistry. Thermochemistry.

Spectrochemistry. Pure Substances.

Mechanics. Sound. Mechanical Instruments. Fluid Mechanics. Engineering Mechanics. Mass

and Scale. Capacity, Density, and Fluid Meters. Combustion Control.

Organic and Fibrous Materials. Rubber. Textiles. Paper. Leather. Testing and Specifications. Polymer Structure. Organic Plastics. Dental Research.

Metallurgy. Thermal Metallurgy. Chemical Metallurgy. Mechanical Metallurgy. Corrosion.

Mineral Products. Porcelain and Pottery. Glass. Refractories. Enameled Metals. Concreting

Materials. Constitution and Microstructure.

Building Technology. Structural Engineering. Fire Protection. Heating and Air Conditioning. Floor, Roof, and Wall Coverings. Codes and Specifications.

Applied Mathematics. Numerical Analysis. Computation. Statistical Engineering.

Electronics. Engineering Electronics. Electron Tubes. Electronic Computers. Electronic

Instrumentation. Process Technology.

Radio Propagation. Upper Atmosphere Research. Ionospheric Research. Regular Propagation

Services. Frequency Utilization Research. Tropospheric Propagation Research. High Frequency

Standards. Microwave Standards.

^Office of Basic Instrumentation ^Office of Weights and Measures.
NATIONAL BUREAU OF STANDARDS REPORT

ISOCANDLE DISTRIBUTION OF

PREPRODUCTION 100-PAR56 LAMP

FOR LEAD-IN SYSTEMS

Prepared by

R. T. Vaughan

R. Wo Crouch

Photometry and Colorimetry Section

Optics and Metrology Division

Tested for

AIRWAYS ENGINEERING DIVISION

CIVIL AERONAUTICS ADMINISTRATION

Washington 25, D. C.

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

The publication, repr Approved for public release by the pa „, is prohibited

unless permission Is o Director of the National Institute of idards, Washington

NBS PROJECT

0201-20-2303

NBS REPORT

3621

Test 21A- 7/5*+

25, D, C. Such perm

cal ly prepared If tha Standards and Technology (NIST) on October 9, 2015

>rt has been specifiort for its own use,

ISOCANDLE DISTRIBUTION OF PREPRODUCTION 100-PAR56 LAMP

FOR LEAD-IN SYSTEMS

By R. T. Vaughan and R. W. Crouch

1.

SCOPE

This report shows the isocandle distribution of two preproduction samples of the IOO-PAR 56 lamp ) as determined from

vertical candlepower distribution measurements taken at rated

voltage.

2.

LAMPS TESTED

The lamps tested are preproduction samples of a new lamp

developed by the General Electric Company for the Airways Engineering Division of the Office of Federal Airways. They are

identified by the numbers U 57U5-B“ (over )'*100W-115V' 1 and are

distinguishable from each other by a

t4 2l* and a “6 U written in

grease pencil on the rear surfaces of the lamps.

These lamps were specified by the Airways Engineering

Division to have bulbs consisting of standard PAR56 reflectors, cover-lenses of the type used on the Navy 399-PAR lamps,

and a power consumption of 100 watts at 115 volts. The voltage and power consumption were selected to meet the requirements of the CAA r4 le ad-in'4 systems.

3.

TEST PROCEDURE

To provide measured horizontal and vertical rotations of

the test lamps, they were mounted in a special fixture on the

table of a goniometer. The primary axis of rotation was

horizontal and normal to the photometric axis. The line perpendicular to the vertical plane of the fixture at the center

of the aperture which enclosed the lamp was taken as the axis

of the lamp. The angles of the goniometer corresponding to

this axis were determined by clamping a plane mirror behind

the aperture of the fixture in the place normally occupied by

the test lamp and then rotating the goniometer until the image

of the standard lamp and its filament appeared to be in line

for an observer having his eye centered with respect to the

photocell. The isocandle curves have been plotted with the

axis of the lamp at the origin of coordinates but the goniometer angles have been indicated to show the relationship

between the figures.

2

J?he candlepower distribution was measured with an automatic photometer, the recording element of which was a Leeds & Northrup recording potentiometer driven in synchronism with the goniometer on which the lamp under test was mounted. The photometer was calibrated with

ts flr lamp No. BS 3315 at a distance of 1 . 9 meters; the photometric distance was 30.C meters (98.4 feet).

When the calibration was completed, a record was made on the candlepower distribution chart. In figure 1 this record has been marked to show the test lamp candle - power which would be equivalent at the photocell to that 01 tne standard lamp.

AH measurements were made with a 60 cycle constant

so

!arce

. adj uste d

< to give 115 volts between the

avf? 7 oKT

iP

£

ermmals. Since total lumen ratings are not available for preproduction lamps, no correction factors were introduced for the lumen output of the test lamps.

4 . RESULTS

^Te ^tiCal 9 andle P°wer distribution curves show a limp

Candlepower of approximately 2.5 kilocandles for each

o Ihe distribution of candlepower as shown in figures 2 and 3 is remarkably free from the irregularities which are usually found in curves of this type.

In the absence of total-lumen ratings, an estimate Ca

5

dl

?

P°We L

for ai

? average lamp of the type tested can be made from the nominal and actual wattage of the

Were °Perated at 96 . 4$ (No. 2) and

thL

b

/l °n^3

1T rated Power. Using the average of these values, 96. 5/^ ? and the formula,

operating lumens

rated lumens

r operating watts > 2.19

rated watts * h„1

f<

- e

1Snn

mat

??

that

,an averaS e lamp of this type operat- at 100 watts may be expected to have a candlepower in the indicated directions equal to the values shown on the isocandle curves increased by the factor 1.08.

General Electric Lamp Bulletin LD-1, October 1950 Page 19. ’ ’

"V *n »i? 30 VW

t? OM
<p.

0

<
NBS

Test

21A-7/54

Figure
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THE NATIONAL BUREAU OF STANDARDS

Functions and Activities

The functions of the National Bureau of Standards are set forth in the Act of Congress, March

3, 1901, as amended by Congress in Public Law 619, 1950. These include the development and

maintenance of the national standards of measurement and the provision of means and methods

for making measurements consistent with these standards; the determination of physical constants and properties of materials; the development of methods and instruments for testing materials,

devices, and structures; advisory services to Government Agencies on scientific and technical

problems; invention and development of devices to serve special needs of the Government; and the

development of standard practices, codes, and specifications. The work includes basic and applied

research, development, engineering, instrumentation, testing, evaluation, calibration services, and

various consultation and information services. A major portion of the Bureau’s work is performed

for other Government Agencies, particularly the Department of Defense and the Atomic Energy

Commission. The scope of activities is suggested by the listing of divisions and sections on the

inside of the front cover.

Reports and Publications

The results of the Bureau’s work take the form of either actual equipment and devices or published papers and reports. Reports are issued to the sponsoring agency of a particular project

or program. Published papers appear either in the Bureau’s own series of publications or in the

journals of professional and scientific societies. The Bureau itself publishes three monthly periodicals, available from the Government Printing Office: The Journal of Research, which presents

complete papers reporting technical investigations; the Technical News Bulletin, which presents

summary and preliminary reports on work in progress; and Basic Radio Propagation Predictions,

which provides data for determining the best frequencies to use for radio communications throughout

the world. There are also five series of nonperiodical publications: The Applied Mathematics

Series, Circulars, Handbooks, Building Materials and Structures Reports, and Miscellaneous

Publications.

Information on the Bureau’s publications can be found in NBS Circular 460, Publications of

the National Bureau of Standards ($1.00). Information on calibration services and fees can be

found in NBS Circular 483, Testing by the National Bureau of Standards (25 cents). Both are

available from the Government Printing Office. Inquiries regarding the Bureau’s reports and

publications should be addressed to the Office of Scientific Publications, National Bureau of Standards, Washington 25, D. C.
f(