Essential Parameters and Auxiliary Gear for Light Sources

Parameters of Light Sources

The common parameters of light sources include luminous flux, mean and useful life, mortality, and distribution of light intensity. Lamps must comply with specific electrical characteristics:

• Voltage and Current Ratings
• Starting Current and Ignition Voltage
• Voltage values of Reactance and Impedance

Luminous Flux, Depreciation, and Lamp Life

The light output of lamps, after the first 100 hours of operation, must not be less than 90% of the nominal light specified in the manufacturer's catalog. Luminous depreciation shall not exceed 5% (meaning the output must be at least 95%).

Average lamp life is the arithmetic mean of the operating hours of all lamps, representing a statistical value. Useful life is the number of hours after which the luminous flux has decreased to a point where the light source is no longer economically profitable. The higher the luminous depreciation, the lower the useful life.

Light Intensity Distribution

The radiated light is influenced mainly by the position of the cap and the shape of the light source. Understanding light distribution is fundamental for the design and development of the luminaire's optical system.

Ancillary Equipment for Discharge Lamps

The performance of discharge lamps diminishes as the current intensity flowing through them increases. Therefore, it is necessary to stabilize the current intensity to prevent lamp destruction, which is achieved using an inductive reactance (ballast) to limit the current.

Furthermore, certain discharge lamps require high voltages for ignition, necessitating the installation of starters. Auxiliary equipment devices (ballasts, capacitors, and starters) are essential for lamp ignition and normal operation.

Ballasts: Current Stabilization Devices

Ballasts are crucial for stabilizing the current flowing through discharge lamps.

Types of Ballasts

Inductive Ballast (Choke)

Composed of a coil with a magnetic core, connected in series with the lamp. This inductive reactance is widely used but offers poor power factor control.

Autotransformers

Controls the current and steps up the voltage. Constituted by two magnetically decoupled windings.

Self-Regulatory Ballasts

These ballasts combine multiple components in an electric circuit. They provide good regulation of current and lamp power.

Two Power Level Ballasts

Designed for energy savings by reducing current intensity and lamp power. They can achieve energy savings in the order of 40%.

Ballast Requirements

Ballasts must meet certain basic specifications to ensure adequate performance.

Capacitors (Condensers)

Capacitors are associated with the reactance, serving for current regulation and power factor compensation. All capacitors must meet certain basic specifications.