The Venture technical glossary outlines key terminologies used in the HID commercial lighting industry.
Arc Tube: A completely sealed quartz or ceramic tube where the electrical discharge (arc) occurs and generates light.
Auxiliary Light: Back-up light source to the HID light; typically a quartz halogen type.
Ballast: A device that, by means of resistance, inductance, capacitance or electronic elements, singly or in combination, controls the current, voltage and waveform to the required values for proper lamp starting and operation for a HID ballast operating at a given supply voltage.
Ballast Characteristic Curve: The curve of lamp wattage vs. lamp voltage over a range of normal lamp voltages, when a HID ballast operates at a given supply voltage.
BTL: The distance from ballast-to-lamp.
Ballast Power Factor: Power consumed by the lamp and ballast (watts) divided by the product of line voltage and line current (“volt-amps” or “VA”); A measure of power quality and of concern to utilities.
Burning Position: The position in which lamps are designed to operate.
Cold Start Time: The amount of time from the application of ballast voltage to ignition.
Color Rendering Index (CRI or Ra): A measure of a light source’s ability to render colours relative to a standard of 100.
Constant Wattage Autotransformer (CWA) Ballast: A magnetic autotransformer lead ballast circuit incorporating a capacitor in series with the lamp; compared to other ballasts the CWA regulates over a wider input voltage range, holding lamp current nearly constant.
Correlated Colour Temperature (CCT): The perceived “colour” of the light emitted by a lamp expressed in Kelvin (K units) Current Crest Factor: The ratio of the peak to the rms value of lamp current; metal halide values range from 1.5 to 1.8.
e-Lamp®: Venture’s 4000K colour temperature pulse start lamps specifically designed for use on high frequency electronic ballasts; capable of dimming down to 35% lamp power.
Economic Life: The number of hours a group of lamps will burn before it is economically and aesthetically advisable to group relamp (typically 60% to 75% of rated life).
Efficacy (Lamp): A ratio of lumens to watts; often calculated with either lamp watts or system watts; measured in lumens per watt (LPW).
Formed Body Arc Tube: Precisely reproducible ellipsoidal arc tube formed by Venture’s quartz sculpting process; has 2/3 less quartz mass than standard arc tubes for equivalent lumens; has no starter electrode.
HID: High Intensity Discharge lamps; includes metal halide, mercury vapour and high pressure sodium.
Hot Restart or Restrike Time: The amount of time from return of power after an interruption to the point of lamp ignition.
Ignitor: An electronic device which provides, by itself or in combination with other circuit components, the appropriate electrical conditions to start a discharge lamp.
Ignitor CWA Control Gear: CWA control gear using an ignitor to start the lamp.
Initial Lumens: The light output of a lamp, based on photometry results, at rated wattage after 100 hours of operation.
Input Voltage at Lamp Dropout (Extinction Voltage): The rms value of supply voltage at which a reference lamp extinguishes when the supply voltage is uniformly reduced from rated value at 2% to 3% of rated voltage per second.
Input Power: See System Power.
Input Watts: The power measured on the input terminals of a ballast which is operating a reference lamp.
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 voltage and RMS lamp current; it is less than unity on magnetic ballasts operating at 50 or 60hz.
Lamp Voltage: The voltage at which lamps operate when they are fully warmed up.
Lamp Wattage: The power consumed by a lamp after warm-up.
Light Centre Length (LCL): The distance from the centre of the arc discharge to the end contact of the base.
Lumens: A measurement of light output; takes into account the human eye sensitivity curve so that more weight is given to the yellow-green part of the light spectrum.
Lumen Maintenance: The lumen output provided by a lamp at a given point in or percentage of its life.
Lumens Per Watt (LPW): A ratio of lumens to watts; often calculated with either lamp watts or system watts; measured in lumens per watt (LPW).
Luminaire Requirements: The type of luminaire a lamp requires; i.e., enclosed or open rated.
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.
Natural White®: Venture’s line of pulse start lamps that have 5000K colour temperature, 90+ CRI and 90% lumen maintenance.
Occupancy Sensor: Control device that dims or turns lights off after the space becomes unoccupied; may be ultrasonic or infrared-actuated.
Open Circuit Current (Line): The RMS current measured through 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 (E27): Designed for open luminaires; has a narrower neck than standard E27 base lamps. Lamp arc tube is surrounded by a protective quartz shroud.
Open Rated Lamp (E39 & E40): Designed for open luminaires. Lamp arc tube is surrounded by a protective quartz shroud.
Operating Current (Line): The power factor corrected current measured through the input terminals of a ballast which is operating a reference lamp.
Operating Voltage: The voltage at which lamps operate when they are fully warmed up.
Peak Lead Ballast: A ballast that produces a highly peaked open circuit voltage wave shape and has a capacitor in series with the lamp.
Photopic Light: Applicable during normal daytime lighting conditions; describes lumen values measured using the high luminance eye sensitivity function centred at 555 nm (yellow-green).
Position Oriented Mogul Base (POMB, EP39, EP40): Used with horizontal burning lamps; has an aligning pin embedded in the base for proper lamp orientation when it is screwed into its socket; should only be used in yellow POMB sockets with a slot in the screw shell to accommodate the aligning pin.
Power Factor (Ballast): The quotient of the ballast input power divided by the product of the rms ballast supply voltage and ballast supply current.
Probe Start Lamp: A metal halide lamp which uses a starter electrode (probe) to assist in starting without the use of an ignitor pulse; also contains a bimetal switch and resistor.
Pulse Start Lamp: Specially designed metal halide lamp that requires a high voltage pulse for starting; has no starter electrode (probe) and has high starting gas pressure.
Rated Life: The number of operating hours at which 50% of most metal halide lamps, or 70% to 80% for some Uni-Form® pulse start lamps, initially installed will still be operating.
Rated Supply Voltage: The voltage for which a ballast or transformer is designed and for which operation and performance characteristics are referred.
Reactor Ballast (Lag Ballast): An inductive component connected in series with an HID lamp to limit the current; uses a coil of wire wound around an iron core connected in series with the lamp.
Regulation: The percent change in lamp watts as the line voltage is changed over the designated voltage range of the ballast.
Restrike: To re-ignite the arc of a HID lamp.
Restrike Control (Hot/Cold Start): A control device that powers an auxiliary lamp in an HID luminaire after a momentary power interruption and when the HID lamp is first turned on.
S/P Ratio: The ratio of photopic lumens to scotopic lumens.
Scotopic Light: Applicable during dark nighttime lighting conditions; describes lumen values measured using the low luminance eye sensitivity function centred at 507 nm (blue-green).
Short-Circuit Current (Ballast): The current at the output terminals of a ballast when the output is shorted (RMS, unless otherwise stated).
Shroud: A quartz cylinder surrounding the arc tube to protect against hot arc tube particles breaking the glass bulb if an arc tube rupture occurs: reduces the risk when using metal halide lamps in open luminaries.
Spectral Power Distribution: The distribution of radiant power (watts) of a lamp as a function of wavelength (nm).
Starter: An electronic device which provides, by itself or in combination with other circuit components, the appropriate electrical conditions to start a discharge lamp.
Starting Current (Line): The RMS current measured through the input terminals of the ballast five to 15 seconds after the lamp has started.
Starting Pulse: A high-voltage, low-energy pulse superimposed on the open circuit voltage of some HID ballasts to aid in starting a lamp.
Sustaining Voltage: The instantaneous voltage available to the lamp from the ballast at the time the lamp current passes through zero.
System Watts: The power measured on the input terminals of a ballast which is operating a reference lamp.
Tipless Arc Tube: An arc tube made without an auxiliary exhaust tube for dosing gases and other ingredients.
Uni-Form®: Venture’s pulse start lamp and ballast systems that contain a formed body arc tube; requires a high voltage pulse for starting; has improved lumen maintenance.
Warm-Up Time: The amount of time from ignition of the lamp to 90% light output.
Watts: A measure of energy (in joules) being used or emitted each second.
White-Lux®: Venture’s line of retrofit metal halide lamps that operate on high pressure sodium ballasts.