Ignitor:
An electronic device which provides, by itself or in combination
with other circuit components, the appropriate electrical conditions
to start a discharge lamp
Initial Lumens:
The light output of a lamp at rated power on a reference ballast
after 100 hours of operation
Input Power:
See System Power
Lag Ballast:
A magnetic ballast having a lagging lamp current with respect to
the supply voltage. Current limiting is primarily inductive; holds
lamp power reasonably constant with respect to lamp voltage variations
Lamp Power
Factor: Power consumed by the lamp divided by the product of
RMS lamp volts and RMS lamp current; It is less than unity on magnetic
ballasts operating at 50 or 60 hz
Lamp Voltage:
The RMS voltage at which lamps operate when they are fully warmed
up
Lamp Power:
The power consumed by a lamp after warm-up, measured in watts
Lamp Regulation:
The ratio of lamp power to lamp voltage often expressed in graphical
format
Lead Ballast:
A magnetic ballast having a leading lamp current with respect to
the supply voltage; current limiting is accomplished by means of
an inductor as well as a capacitor connected in series with the
lamp; this includes CWA and CWI ballasts
Light Center
Length (LCL): The distance from the center of the visible arc
discharge to the bottom contact of the base
Line Regulation:
The ratio of lamp power to ballast input voltage often expressed
as a percentage
Lumens:
A measurement of light; takes into account the human eye sensitivity
curve so that more weight is given to the yellow-green part of the
light spectrum (photopic)
Lumen Maintenance:
The lumen output of a lamp at a given operating time or a percentage
of 100 hour lumens at that time
Lumens Per Watt
(LPW): See Efficacy
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Maximum
Overall Length (MOL): The maximum allowable distance from the
top of the glass bulb to the end contact of the base
Mean Lumens:
Light output at 40% of rated lamp life
Normal (Low)
Power-Factor (NPF) Ballast: A ballast designed so that the input
power factor is less than 90% when the ballast is operated at the
rated supply voltage using a reference lamp
Open Circuit
Current (Line): The RMS current measured at the input terminals
of a ballast with lamp removed or inoperative
Open Circuit
Voltage, Ballast (OCV): The voltage across the output terminals
of a ballast when no load is connected (RMS, unless otherwise stated)
Open Rated
Lamp (Medium Base): Designed for open luminaires; has a narrower
neck than standard medium base lamps in order to fit into an exclusionary
medium EX26 socket
Open Rated
Lamp (Mogul Base): Designed with an extended contact pin on
the bottom of the base; should be used with an open fixture mogul
sockets (EX39) which prevents electrical contact if a non-O-rated
lamp is used
Operating
Current (Line): The RMS current measured at the input terminals
of a ballast which is operating a reference lamp
Operating
Voltage: See Lamp Voltage
Opti-Wave™
Ballasts: A Venture lag (magnetic) or electronic ballast designed
with a low current crest factor for improved lamp performance. Opti-Wave
lag ballasts are also optimized for low open circuit current
Peak
Lead Ballast: A CWA ballast that produces a highly peaked open
circuit voltage wave shape and a peaked current wave shape
Photopic
Light: Describes lumen values measured using the high luminance
eye sensitivity function centered at 555 nm (yellow-green)
