The Rating Problem — Lamps in Luminaires

The standard “Recommended Practice for Reporting Photometric Performance of Incandescent Filament Lighting Units Used in Theatre and Television Production,” has been very useful for the industry. It, however, refers only to such lamp specifications as nominal wattage, design voltage, rated life, specified initial lumens and approximate color temperature. Little is stated about how these factors vary for individual samples of a particular lamp type. Testing laboratories can determine the performance of a specific lamp, but the user has limited knowledge and facilities for dealing with lamp rating variations that may affect acceptability for a specific use. The incandescent lamp is a highly precise device with operating parameters principally governed by the tungsten filament. Normally voltage is the first and basic factor establishing the lamp design based on the available power supply, and wattage is established by desired performance. Life, lumens and color temperature are all related variables with well-established interrelationships. It is important to know what variations may be expected in these factors for any specific lamp. Various illustrations show the effects on a lamp's performance in a luminaire. Other factors which can affect performance are considered along with the tolerances which can be anticipated.

Print ISSN

0361-4573

Published

1969-12

Content type

Original Research

DOI

10.5594/J10759