As starters of fluorescent lamps work
The starter represents the small gazorazryadyony lamp of the glow discharge. The glass kolyoba is filled with inert gas (neon or mix helium-hydrogen) and is located in the metal or plastmasyosovy body on which upper cover there is the smoyotrovy window.
In some designs of starters the observation port is absent. Electrofood has the starter two. Distinguish asymmetrical and symmetric konyostruktion of starters. In asymmetrical starters one electrode motionless, and the second mobile, is made
Now the greatest rasproyostraneniye was received by the symmetric design of starteyor at which both electrodes are produced from bimetal. This design has the number of advantages in comparison with asymmetrical.
Ignition tension in the starter of the glow discharge is chosen so that it was less rated voltage of network, but it is more than working nayopryazheniye which is established on the lyumiyonestsentny lamp at its burning.
At inclusion of the scheme on nayopryazheny networks it completely will be attached to the starter. Electrodes of the staryoter are opened, and in is mute there is the glow discharge. In the chain there will pass small current (20-50 mA). This current nayogrevat bimetallic electrodes, and they, being bent, will close the chain, and the glow discharge in the starter will stop.
Current which will warm up lamp cathodes will begin to pass through the throttle and consistently connected cathodes. The size of this current is defined by the induced resistance of the throttle chosen thus, chtoyoba current of preliminary heating of katoyod by 1,5 2,1 times exceeded rated current of the lamp. Duration of predvaritelyyony heating of cathodes is defined vreyomeny during which electrodes of the staryoter remain closed.
When elekyotroda of the starter are closed, they cool down, and after the certain period called by engagement time, electrodes razyomykatsya. As the throttle has big inductance, at the time of disconnection of electrodes of the staryoter in the throttle there is the big impulse the napryazheyoniya lighting the lamp.
After ignition of the lamp in the chain current, ravyony to the lamp rated working current will be established. This current obuyoslovit such voltage drop on the throttle that the nayopryazheniye on the lamp will become approximately equal to the half of rated voltage of network. As the starter включен parallel to the lamp, tension on will be mute equally to tension on the lamp and because it insufficiently for ignition of the glow discharge in the staryoter, its electrodes will remain opened at the lamp goreyoniya.
The possibility of ignition of the lamp depends on the dlitelyyonost of preliminary heating of cathodes and size of the current passing through the lamp at the time of disconnection of electrodes of the starter. If the rupture of the chain occurs at small value of current, then size induced in the throttle э. of page and, therefore, tension attached to the lamp can be insufficient for its ignition, and the lamp will not be lit. Therefore if in the first attempt the starter does not light the lamp, he at once will automatically repeat the described process until there is ignition of the lamp. Ignition of the lamp has to be provided to Soyoglasno with GOST on starters in time up to 10 sec.
Parallel to electrodes of the starter the kondenyosator with a capacity of 0,003-0,1 microfarad is included. This condenser is obychyono placed in the starter body. The condenser vypolyonyat two functions: reduces the level of radio interferences, vozniyokayushchy at engagement of electrodes of the starter and created by the lamp; on the other hand, this kondensayotor exerts impact on processes of ignition of the lamp. The condenser reduces the impulse size the napryazheyoniya formed at the time of disconnection of electrodes of the staryoter and increases its duration.
In the absence of the condenser tension on the lamp very quickly vozyorastat, reaching several thousand volts, but the prodolzhiyotelnost of its action very small. In these usloyoviya reliability of ignition of lamps sharply decreases. To Kroyoma of that, turning on of the condenser parallel to elektroyoda of the starter reduces probability of welding or as speak, the sticking of electrodes which is turning out in the reyozultata of formation of the electric arc at the time of disconnection of electrodes. The condenser promotes fast arc extinction.
Use of condensers in the starter does not obespechiyovat full suppression of the radio interferences created by the lyuyominestsentny lamp. Therefore it is dopolniyotelno necessary to install on the entrance of the scheme two condensers with a capacity not less than 0,008 microfarad everyone, soyedinenyony it is consecutive, and to ground the average point.
One of the recommended ways of decrease in level of radio interferences is application of throttles with the simmetriyorovanny winding where the winding of the throttle of the razdeleyon on two absolutely identical parts having ravyony number of the rounds which are reeled up on one the general the serdechyonik.
Each part of the throttle is connected consistently to one of lamp cathodes. At inclusion of it дросселя both of its cathodes work with the lamp in identical conditions that reduces the level of radio interferences. Now, as a rule, the throttles released by the industry are produced with the symmetrized obmotyoka.
In the scheme because of availability of the throttle current through the lamp and mains voltage will not match on the phase, i.e. they will not reach at the same time the zero and maximum values. As is well-known from the alternating-current theory, in this case current will lag behind on the phase mains voltage on some corner which size is defined by the ratio of the inductive soyoprotivleniye of the throttle and pure resistance of all network. Such schemes are called lagging behind.
In some cases uses of lyuminestsetny lamps it is required to create such conditions when current through the lamyopa would advance mains voltage on the phase. Such schemes are called advancing. For performance of this condition consistently with the throttle the konyodensator which capacity is calculated it obrayozy that its capacitive reactance was more induced resistance of the throttle joins.
In the advancing ballast during ignition of the lamp current of preliminary heating of cathodes has insufficient size. For elimination of this phenomenon it is necessary to increase current of preliminary heating for the period of ignition of the lamp that can be made if partially to compensate capacity by inductance. The chain of the starter joins additional inductance in the form of the neutralizing coil.
At short circuit of electrodes of the starter this neutralizing coil turns on consistently with the throttle and the condenser, the general inductance of the scheme vozrastayot, and together with it current of preliminary heating increases. After disconnection of electrodes of the starter the komyopensiruyushchy coil is switched-off, and she does not participate in the operating duty of the lamp. The inductance of the additional coil compensates the capacitor capacitance, ustanovyolenny in the starter. Therefore the dopolniyotelny condenser with a capacity not less than 0,008 microfarad which is switched on parallel to the lamp and carrying out in this case the role of the noise suppressing condenser is entered into the scheme.
One of shortcomings of the considered schemes - low power factor. It makes size 0,5-0,6. The Puskoreguliruyushchy devices (PRA) executed on the basis of these schemes belong to group of so-called noncompensated devices. When using tayoky devices according to the rules of the device of elektroyoustanovka (RDE) for increase in low power factor it is necessary to provide the group komyopensation of electrical power factor providing its doyovedeniye for all lighting installation to the veliyochina 0,9-0,95.
At impossibility or the economic neeffektivyonost of application of group compensation of electrical power factor use schemes in which in addition parallel to the lamp the condenser of sufficient capacity chosen so that the electrical power factor of the scheme raised up to the size of 0,85 - 0,9 turns on. PRA made according to this scheme is called compensated. Calculations show that for lamps the moshchyonost of 20 and 40 W at voltage of 220 V the capacity of the konyodensator is 3-5 microfarad.
The main lack of starter schemes of ignition - their low reliability which is caused ненадежностью operation of the starter. Reliable operation of the starter also depends on the voltage level in the power line. With tension sniyozheniye in the power line time necessary for the warming up of bimetallic elekyotrod increases, and at reduction of tension more than for 20% rated the starter does not provide the konyotaktirovaniye of electrodes at all, and the lamp will not be lit. Means, with reduction of tension in the power line time of ignition of the lamp increases.
At the fluorescent lamp in process of aging increase in its operating voltage, and at the starteyor nablyuyodatsya, on the contrary, with growth of service life tension of the zazhiyoganiye of the glow discharge decreases. As a result of it it is possible that at the burning lamp the starter will begin to work and the lamp dies away.
At disconnection of electrodes of the starter the lamp lights up and observed migayony lamps again. Such blinking of the lamp, in addition to the unpleasant visual feeling caused by it, can lead to overheating of the throttle, its exit out of operation and damage of the lamyopa. The similar phenomena can take place at the isyopolzovaniye of old starters in network with the lowered voltage level. At emergence of blinkings of the lamp it is necessary to replace the starter with new.
Starters have considerable dispersions of time of the konyotaktirovaniye of electrodes, and it very often nedostatochyono for reliable preliminary heating of cathodes of lamps. As a result the starter lights the lamp after neyoskolky intermediate attempts that increases the dliyotelnost of the transition processes reducing the term of the sluzhyoba of lamps.
Common fault of all single-tube schemes - the nevozyomozhnost to reduce the pulsation of the luminous flux created by one lyuminestsentyony lamp. Therefore such schemes can be applied in rooms where several lamps ustanavliyovatsya, and in case of their use for group of lamps it is recommended to include for the purpose of reduction of the pulsayotion of the luminous flux of the lamp in different phases of the three-phase chain. It is necessary to aim at that illumination in each point was created not less than from two-three lamps included in different phases of network.
Two-lamp schemes of inclusion. Application of dvukhyolampovy schemes of inclusion gives the chance to reduce the pulsation of the total luminous flux as pulyyosation of the luminous flux of each lamp happen not at the same time, and to some shift on time. To Poyoety the total luminous flux of two lamps will never be equal to zero, and fluctuates about some sredyony value with the frequency, smaller, than at one lamyopa. Besides, these schemes provide high коэффициент set capacities the lamp - PRA.
The greatest distribution was gained by the dvukhlampoyovy scheme called often by the scheme with the split phase. The scheme consists of two elements branches: lagging behind and advancing. In the first branch current lags behind on the phase tension on the corner 60 °, and in the second - opeyorezhat on the corner 60 °. Thanks to it current in the external circuit will almost match on the phase tension, and the electrical power factor of all scheme will make size 0.9-0.95.
This scheme can be carried to group kompensiyorovanny, and in comparison with the single-tube nekompensiyorovanny scheme it has that advantage that it is not required to take additional measures for the electrical power factor povyyosheniye. At production of PRA according to this scheme the general consumption of constructional materials is less, than for two and single-tube devices. Now the large number of different types of the devices executed according to this scheme is issued.Top