As the external environment influences work and characteristics of fluorescent lamps
Let's consider how influence Wednesday in which the fluorescent lamp, and conditions of its work works for its hayorakteristik.
It is necessary to carry temperature and the vlazhyonost of the ambient air to the external factors influencing work of lyumiyonestsentny lamps.
Service life, light otyodacha and power of lamps depend on the way their zazhigayoniya, numbers of inclusions of the lamp, the form of the current passing through the lamp and on constancy of tension of the power line.
The major moments defining quality of luminescent lighting are the pulsation of the luminous flux created by lamps and degree of the poyodavleniye of the radio interferences appearing at ignition and burning of lamps. Ambient air temperature renders vliyayony on the mercury vapor pressure in the lamp as with izmeneyoniy air temperatures temperature the tube steyonok changes.
Standard fluorescent lamps of the rasyoschitana for work at the temperature of surrounding vozyodukh of 15 — 40 °C also have the maximum light return at the temperature of 20 — 25 °C. It is possible to create lamps, priyosposoblenny to work at lower temperatures, for example, the 125 W lamp has the best light characteristics in the range of temperatures from — 15 up to +10 °C. At the deviation of the surrounding temperayotura from best values which the lamp is expected its luminous flux decreases. So, at the tempeyoratura of walls of the tube about 0th °C the luminous flux of the lamp falls up to 10 — 15% of rated value, and at the preyovysheniye of their temperature up to 50 °C it decreases approximately by 0,8% for each GS of temperature increase the steyonok.
The luminous flux of the lamp is also influenced by change of conditions of heat extraction from it which are defined nayolichiy or lack of the movement of the surrounding vozduyokh. They say that the lamp is afraid of "drafts".
Spoyosoba of ignition of the lamp depend on ambient air temperature. Tension of ignition of the lamp will have the minimum value at the temperature of walls of the tube corresponding to optimal conditions of ionization of vapors of mercury. If temperature decreases, then transformation of mercury into couples is slowed down, the number of atoms of mercury in gas are not enough for providing the beginning of the razyoryad in the lamp, additional sources of svobodyony electric charges are necessary.
Atoms of the gas filling the pipe — argon can only become such source, but tension at which ionization of atoyom of argon begins is 50% higher, than the corresponding napryayozheniye for mercury atoms. Therefore, at the low temperature for ignition of the lamp it is required to give on it more high tension. From this situation sleyodut the conclusion that at low ambient air temperatures of the lamp will be lit with big zatrudneyoniya.
In this regard in installations of outside lighting for ensuring ignition of fluorescent lamps in hoyolodny weather it is necessary to resort to special meyora.
Lamps place in glass protective shirts or the general cap. Heat losses of the lamp create necessary heating of internal volume of the casing and obesyopechivat ignition of lamps at low temperatures. Sometimes at especially low temperatures it is possible to nablyuyodat in the initial stage of ignition the luminescence only of konyots of lamps, and after sufficient warming up of all volume of the casing there is ignition of the lamp.
The increased humidity of the environment causes formation of the film on the surface of the tube reducing its surface resistance. Change of poverkhnostyony resistance of the tube influences lamp zazhiyoganiye tension. At the relative humidity of 75 — 80% tension of ignition has the maximum value.
With change of the relative humidity in this or that party tension of ignition of the lamp umenyyoshatsya. For the exception of influence of humidity on napryayozheny ignitions of lamps they have to be supplied with the conductor strip or have the special vodoottalkiyovayushchy covering.
Service life of lamps with other things being equal zaviyosit from quantity of the oxidic covering on cathodes and the skoyorost of its expenditure in the course of burning. During the lamp operating time the oxidic covering gradually испаряется, and parts of oxide, being besieged on tube walls, lead to blackening of its ends near cathodes.
Most violently process of evaporation of oxide protekayot at the time of ignition of the lamp. Therefore it is necessary to priniyomat measures for reduction of influence of the starting mode on service life of lamps. The main condition has to be for this purpose satisfied — it is necessary to light the lamp only at rather heated-up cathodes. If on the lamp to give tension sufficient for ignition in it of discharge, and cathodes will have at the same time temperature below neobyokhodimy to start thermal electron emission, then katoyoda will undergo the strengthened ionic bombardment, having high energy, and it will cause the sharp rasyopyleniye of oxide. Such process of inclusion of lamps is nazyvayot cold ignition.
Tension in network, as a rule, in the course of the ekspluyoatation of lamps does not remain to constants in size and moyozht to change in quite wide limits. Parayometra of fluorescent lamps change together with tension izmeyoneniye in the power line, however in this case fluctuations of tension influence harakyoteristik of lamps less, than it takes place for nakaliyovaniye lamps.
Depending on type (inductive or capacity) and sizes of ballast resistance the elekyotrichesky mode of the lamp at voltage variation in network changes.
At inductive ballast with increase the napryazheyoniya in network tension on the lamp falls, current and the moshchyonost of the lamp increase, and light return umenyyoshatsya. On average for each 1% of change the napryazheyoniya in network the power, the luminous flux and current change for 2%. At very strong undervoltage in seyot, more than 25% rated, lamps will not be зажигаться in general.
At capacity ballast the nature of dependence ostayotsya same, as well as at inductive ballast. However R this case for each 1% of voltage variation in networks, power, the luminous flux and current change on average only for 1%.
The luminous flux radiated by the light source at the power supply by its alternating current does not remain to constants, and changes in size, following changes of current through the lamp. At the moment when the current passing through the lamp has zero value, the luminous flux is equal to zero and sozdavayeyomy the lamp. Therefore, light lamps of sequins pulses with the double frequency in relation to the frequency of network.
When lighting by glow lamps we not zameyochay pulsations of the luminous flux because of the thermal ineryotsionnost of filament.
Fluorescent lamps do not possess such inertsiyoonnost therefore the termination of current in them leads to immediate extinction of discharge and disappearance of the sveyocheniye of the lamp. Phosphors have property of the posleyosvecheniye, i.e. during some period after the termination of their radiation by the ultra-violet izyolucheniye they continue to radiate visible light that smoothes the pulsation of the luminous flux of the lamp. For different types of phosphors time and intensity of afterglow different.
The intensity of the pulsation of the luminous flux, sozdavayeyomy fluorescent lamps, also depends on the dliyotelnost of initial and final pauses of current which, in turn, are defined by ballast type.
At illumination of the moving or rotating predyomet the pulsing luminous flux can появиться the so-called stroboscopic effect, svyazanyony with distortion of visual perception. If, the nayoprimer to light with such pulsing light potoyok the wheel rotating with the certain angular speed, then at equality or frequency rate of the angular skoroyosta of rotation of the wheel to flow ripple frequency it at this lighting will seem motionless. If the angular speed of rotation is less than the frequency of the pulyyosation, then will seem to us that the wheel vrashchayotsya slowly in the opposite direction in comparison with the valid rotation sense.
Such optical illusion is dangerous from the point of view of safety measures as at the same time getting injured is possible. Besides, the pulsation of the sveyotovy flow exerts impact on efficiency of zriyotelny work, causing the increased weariness of the organ of vision. The phenomenon of the stroboscopic effect moyozht to arise not only in the presence of moving objects in sight of working, but also at the vypolyoneniye of any work when there is the relative movement of the eye and the lit subject. In this regard at the device of luminescent lighting sleyodut to take measures to the maximum decrease in the pulyyosation of the luminous flux.
During the operation of the fluorescent lamp and at the moments of its ignition the electromagnetic oscillations lying in RF spectrum which can sozdayovat the radio interferences preventing normal work of the radioyoapparatura are radiated. The source of the hindrances going to surrounding space and partially to network are arc разряд in the lamp and also the sparking on cathodes depending on quality of processing of the tungsten spiral and хорошего couplings of the spiral with the oxidic covering. Starters at the time of which razyoryv of contacts there are electromagnetic oscillations can also be Istochniyok of hindrances. When developing schemes of inclusion of lamps prikhoyoditsya to take measures to decrease in level of the radio interferences created by the lamp and its puskoreguliruyushchy apparatuyory.Top