Crestron electronic Green Light GLPS-HSW-FT - Manual (Page 81)

Crestron Commercial Lighting Design Guide
77
Appendix C – Glossary of Lighting Ter
m
s
LUMINANCE: A photometric term that quantifies brightness of a light
source or of an illuminated surface that reflects light. It is expressed as
foot lamberts (English units) or candelas per square meter (Metric units)
LUX (LX): The metric unit of measure for illuminance of a surface. One
lux is equal to one lumen per square meter. One lux equals 0.093 foot
candles
M
MAINTAINED ILLUMINANCE: Refers to light levels of a space at other
than initial or rated conditions. This term considers light loss factors
such as lamp lumen depreciation, luminaire dirt depreciation, and room
surface dirt depreciation
MAGNETIC LOW-VOLTAGE (MLV): Magnetic low-voltage lighting uses a
magnetic (core and coil technology) transformer to convert line voltage
(120 VAC) to low voltage (typically 12 VAC). This lower voltage is then
used to power an incandescent low-voltage lamp. Recessed lights are
most often magnetic low-voltage. Magnetic low-voltage lights tend to be
larger and heavier than electronic low-voltage
MERCURY VAPOR LAMP: A type of high intensity discharge (HID) lamp in
which most of the light is produced by radiation from mercury vapor.
Emits a blue-green cast of light. Available in clear and phosphor-coated
lamps
METAL HALIDE: A type of high intensity discharge (HID) lamp in which
most of the light is produced by radiation of metal halide and mercury
vapors in the arc tube. Available in clear and phosphor-coated lamps
MR-16: A low-voltage quartz reflector lamp, only 2" in diameter.
Typically the lamp and reflector is one unit, which directs a sharp,
precise beam of light
N
NADIR: A reference direction directly below a luminaire, or "straight
down"
NEMA: Abbreviation for National Electrical Manufacturers Association
NEON/COLD CATHODE: Highly inductive boost transformer for neon/cold
cathode lighting
NIST: Abbreviation for National Institute of Standards and Technology
NPF (NORMAL POWER FACTOR): A ballast/lamp combination in which no
components (e.g., capacitors) have been added to correct the power
factor, making it normal (essentially low, typically 0.5 or 50%)
O
OCCUPANCY SENSOR: Control device that turns lights off after the space
becomes unoccupied. May be ultrasonic, infrared or other type
OPTICS: A term referring to the components of a light fixture (such as
reflectors, refractors, lenses, louvers) or to the light emitting or light-
controlling performance of a fixture
P
PARABOLIC LUMINAIRE: A popular type of fluorescent fixture that has a
louver composed of aluminum baffles curved in a parabolic shape. The
resultant light distribution produced by this shape provides reduced
glare, better light control, and is considered to have greater aesthetic
appeal
PARACUBE: A metallic coated plastic louver made up of small squares.
Often used to replace the lens in an installed troffer to enhance its
appearance. The paracube is visually comfortable, but the luminaire
efficiency is lowered. Also used in rooms with computer screens
because of their glare-reducing qualities
PHOTOCELL: A light sensing device used to control luminaires and
dimmers in response to detected light levels
PHOTOMETRIC REPORT: A photometric report is a set of printed data
describing the light distribution, efficiency, and zonal lumen output of a
luminaire. This report is generated from laboratory testing
POWER FACTOR: The ratio of the AC Volts x Amps through a device to
the AC wattage of the device. A device such as a ballast that measures
120 Volts, 1 Amp, and 60 Watts has a power factor of 50% (Volts x Amps
= 120 VA, therefore 60 Watts/120 VA = 0.5). Some utilities charge
customers for low power factor systems
PREHEAT: A type of ballast/lamp circuit that uses a separate starter to
heat up a fluorescent lamp before high voltage is applied to start the
lamp
Q
QUAD-TUBE LAMP: A compact fluorescent lamp with a double twin tube
configuration
R
RADIO FREQUENCY INTERFERENCE (RFI): Interference to the radio
frequency band caused by other high frequency equipment or devices in
the immediate area. Fluorescent lighting systems generate RFI
RAPID START (RS): The most popular fluorescent lamp/ballast
combination used today. This ballast quickly and efficiently preheats
lamp cathodes to start the lamp. Uses a "bi-pin" base
ROOM CAVITY RATIO (RCR): A ratio of room dimensions used to quantify
how light will interact with room surfaces. A factor used in illuminance
calculations
REFLECTANCE: The ratio of light reflected from a surface to the light
incident on the surface. Reflectances are often used for lighting
calculations. The reflectance of a dark carpet is around 20%, and a
clean white wall is roughly 50% to 60%
REFLECTOR: The part of a light fixture that shrouds the lamps and
redirects some light emitted from the lamp
REFRACTOR: A device used to redirect the light output from a source,
primarily by bending the waves of light.
RECESSED: The term used to describe the doorframe of a troffer where
the lens or louver lies above the surface of the ceiling.
REGULATION: The ability of a ballast to hold constant (or nearly constant)
the output watts (light output) during fluctuations in the voltage feeding
of the ballast. Normally specified as +/- percent change in output
compared to +/- percent change in input.
RELAY: A device that switches an electrical load on or off based on small
changes in current or voltage. Examples: low voltage relay and solid
state relay
RETROFIT: Refers to upgrading a fixture, room, or building by installing
new parts or equipment
REVERSE PHASE DIMMING: Rather than attempting to restrict the
amplitude of the current flowing through a lamp, as in other forms of
dimming, reverse phase control works by switching off the end part of
each cycle of the alternating current supply