This document provides information on fluorescent lighting fixtures and lamps. It discusses the components of fluorescent lamps including the glass tube, mercury vapor, phosphor coating, and inert gas. It describes different types of fluorescent lamps such as pre-heat starting hot-cathode lamps, cold cathode lamps, instant-starting hot-cathode lamps, and rapid-start lamps. It also discusses the functions of starters, ballasts, and the average lifespan of fluorescent lamps.

1. INFORMATION SHEET 5.1
FLUORESCENT LIGHTING
FIXTURES

2. FLUORESCENT LAMP
• a form of electric discharge light source. It
consists of a glass tube containing mercury
vapor at a low pressure and inert gas like
argon and krypton. The interior is coated
with phosphor, which glows or fluoresces
when exposed to ultraviolet light.

3. PEC Rules on Wire Dressing and Termination:
Article 6.3.1.3 Live Parts. Fixtures, lamp holders,
lamps, rosettes, and receptacles shall have no live parts
normally exposed to contact. Exposed accessible terminals
in lamp holders, receptacles, and switches shall not be
installed in metal fixture canopies or in open bases of
portable table or floor lamps.
All joints/splices to be done must be properly
insulated with spaghetti sleeving, wrapped with electrical
tape having a similar thickness of the conductor used.

4. TYPES OF ELECTRIC
DISCHARGE
FLUORESCENT
LAMPS

5. Pre-heat starting,
hot-cathode
requires starter (glow
switch) and is pre-heated
during starting. It uses a
ballast to produce high
voltage to start the lamp
into operation and to limit
the flow of current.

6. Operation of pre-heat type fluorescent lamp
The tube filaments, starter (glow switch), and ballast are all
in series, which constitute a complete circuit once the switch, is
closed. As a current flow through, the gas (inert) inside the starter
glows and the electrodes are heated. Since one of the electrodes is
bi-metal, it bends and makes contact with the other. At this instant,
the circuit is metallically complete. The filaments of the fluorescent
tube are then heated and partial ionization takes place. The bi-
in the starter cools and the contacts open. The magnetic field in the
ballast collapses rapidly producing an inductive kick, which
establishes a current between the filaments and fires the tube into
operation.

7. Cold cathode
Requires high voltage in its
operation. This lamp has electrodes
made of thimble-type iron. It is not
pre-heated and does not require a
starter for starting. Special high
voltage transformers operate it.
Neon and mercury lamps are
classified under cold cathode
lamps.

8. Instant-starting,
hot-cathode
The lamp cathode in the instant-
start is not pre-heated. Sufficient
voltage is applied across the
cathodes to create an
instantaneous arc. As in preheat
circuit; the cathodes are heated
during lamp operation by the arc.
The instant-start lamp require
single-pin bases, are generally
called slim line lamps.

9. Hot-cathode,
rapid-start
These are similar in construction to
the preheat lamps; the basic
difference is in the circuitry. This
circuit eliminates the delay inherent
in preheat circuits by keeping the
lamp cathodes constantly
energized (preheated). When the
lamp circuit is energized, the arc is
struck immediately.

10. Classifications
of Fluorescent
Lamp

11. Regular
Fluorescent
Lamp

12. Compact
Fluorescent
Lamp

13. Parts and functions of fluorescent
lamp
C:UsersHPDesktopCLIFFORDless
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14. Function of a Starter
Current moves in utilizing the rare gas as
conducting means and the rare gas produces a
“glow”. The glow generates heat and causes the
bimetallic blade to expand.
When the bimetallic blade is heated, it changes
shape and touches the fixed contact. The close
contacts of the two starter contacts produce an
path for the current to flow.

15. In common with all gaseous discharge lamps, the
fluorescent must be provided with some device for
limiting the current drawn by the discharge. Without
a limiting device, the current would rise to a value
that would destroy the lamp. A device or auxiliary
called ballast can best meet this requirement.
The ballast for operating lamps on an alternating
current consists of a small choke coil woven on an
iron core.

16. Important Functions of a Ballast:
1. It preheats the electrodes to make available a
large supply of the electron.
2. It provides a surge of relatively large potential
start the arc between the electrodes.
3. It prevents the arc current to increase beyond
the limit set for each size and lamp.

17. THE LIFE SPAN OF FLUORESCENT LAMP
The life of fluorescent lamp is affected not only in the
fluctuation of voltage and current but also by the
of times it is started. Electron emission material is
“sputtered off” from the electrodes continuously during
the operation of the lamp and in larger quantities each
time the lamp starts.
Many fluorescent lamps have a rated average life span
to 30,000 continuous burning hours but with an average
of 3 hours burning per start, it could only last for 12,000
hours.