Electric lighting fixtures are used to fix the light source, supply of electricity to it, appropriate shaping of the luminous flux and to protect the light source against external influences. The main components of the luminaires are diffusers and reflectors. The lampshades provide a mechanical cover for the light source, and at the same time they protect the eyes from glare through a distracting effect. The reflectors are designed to increase the luminous intensity in a certain direction. Spherical reflectors are used, parabolic, ellipsoidal and multi-curved.
The characteristic feature of the lighting fixtures is their light distribution curve. This curve is given in the catalogs in the form of a diagram of the luminous intensity of the luminaire la in the direction of a given angle a as a function of this angle in relation to a light source with a flux 1000 lm.
The characteristic feature of the lighting fixtures is also their efficiency. It is a measure of the luminous flux losses caused by the absorption of a part of the radiation energy by the luminaire.
The efficiency of luminaires is significantly reduced as a result of their dust and dirt. Therefore, the fittings should be periodically cleaned during operation.
Light fixtures, like other electricity consumers, it is divided into classes of protection against electric shock and degrees of IP protection against external influences. The division of lighting fittings depending on the degree of protection against external influences is given in the table.
Classification of luminaires according to the IP protection levels
Depending on the distribution of the luminous flux in space, lighting fixtures are divided into 5 class. The division of luminaires into classes and the corresponding division of the luminous flux are given in the table.
Classes of lighting fixtures.
Depending on the type of light source, the luminaires are divided into the following groups:
— oprawy do żarówek,
- fixtures for fluorescent lamps,
- fixtures for mercury lamps,
- fixtures for sodium lamps,
— oprawy do rtęciowo-żarowych,
— inne oprawy.
In addition, lighting fixtures can be divided depending on their purpose. These will be the following groups:
— oprawy oświetleniowe przemysłowe,
— oprawy oświetleniowe zewnętrzne,
— oprawy oświetleniowe do pomieszczeń użyteczności publicznej,
— projektory oświetleniowe,
— oprawy oświetleniowe o specjalnym przeznaczeniu.