PROJECTOR LAMPS are installed in indoor and
outdoor display lighting fixtures. They use a self-
contained reflector but have an advantage over the
reflector type since they are suitable for extreme
temperature conditions and provide more accurate light
HEAT AND DRYING LAMPS, available with
built-in reflectors or with separate reflectors, are an
inexpensive answer to a requirement for instantaneous
infrared energy. The reflector bulb keeps the initial cost
to a minimum and provides a new reflecting surface
with each new lamp.
HARD-GLASS LAMPS, made of special glass
with high resistance to thermal shock, are effective
where rain, splashing liquids, insects, snow, fixture
parts, or hot metallic spray may touch the glass bulbs.
VIBRATION SERVICE LAMPS are available
that withstand excessive vibration that cannot be
eliminated by flexible fixture mounting.
Where the lamp will be subjected to shock, such as
at the end of a drop cord or near machinery, you will
want to select ROUGH SERVICE LAMPS. With
filament supports, these lamps can withstand severe
shocks without failure.
High-cost replacement areas, such as towers,
industrial high bays, theater marquees, halls, and
stairwells, are lighted with LONG-LIFE LAMPS.
QUARTZ-IODINE LAMPS offer a concentrated
source of incandescent light with excellent light control
characteristics, good color, and a life twice that of
regular general service incandescent lamps. They
depreciate at a lower rate than the general service lamp.
The lamp cost is considerably higher, however, than a
general service lamp, and a special fixture is required.
There are two principal types of fluorescent lamps:
instant-start and rapid-start preheat lamps. Both have
practically the same physical dimensions but different
internal construction. The type of circuit in which the
lamp should be used is etched on the end of the lamp.
The rapid-start preheat lamp operates satisfactorily with
either the preheat or rapid-start circuits. It has a short
lamp life in an instant-start circuit. The instant-start
lamp operates satisfactorily with an instant-start ballast,
burns out the ballast in a rapid-start circuit, and does not
light in a preheat circuit. Preheat lamps dominated the
field for many years but are no longer considered a
major type. They continue to be in use, however,
particularly in fixtures using lamps smaller than 40
Examples of circuits for the major types are readily
found in current manufacturers publications. Example
of some circuits are shown in figure 5-76. The 4-foot
rapid-start lamp is the preferred lamp for most
Figure 5-76.Representative fluorescent circuits.