SU287709A1 - - Google Patents

Description

Pulsed gas-discharge light sources, owing to their high light-intensity characteristics and relatively small dimensions, are becoming more and more widespread in various fields of technology. In particular, they begin to appear as light sources for film projectors.

3 different cases of imimus gas discharge nred1; There are various requirements for both the lamps and the electric threading schemes and their operation. Among these requirements, one of the most important is the requirement of providing the necessary frequency of light pulses. Depending on the required frequency of the light pulses, devices using flash lamps can be divided into two groups: devices in which the frequency of the light pulses can be a multiple of the frequency of the sech (50 or 100 gi), and instruments in which the frequency of the light pulses should be different from the frequency of the network. In the latter case, the circuit of the power supply device should have a frequency driver and a duration of nmnulses. Power supply and operation of pulsed gas discharge lamps with a pulse frequency different from the mains frequency (asynchronous varnant) are usually complicated and cumbersome.

It is also known to use semiconductor triodes for control) 1i and domal lalgpa. The dimensions and weight of the device made on such triodes are much smaller, but they are nevertheless large enough to prevent the use of pulsed gas discharge lamps in small-sized devices, pappmer, in any eight-millimeter-sized projector.

Also known are devices for powering a pa6oToii pulsed gas discharge | | Lamps for the case when the frequency of light pulses is a multiple of the frequency of the setpoint (50 or 100 Hz).

The complexity of devices for powering and controlling the operation of pulsed gas discharge lamps, both for synchronization and synchronous operation with the network, prevents the further expansion of the application of pulse-type gas discharge, while the engineering and dimensional parameters of the lamps create for this all the conditions . In particular, this circumstance does not use imimage lamps as a source of light for sixteen i; eight meter optical love projection equipment.

Flashlights for flash lamps.

For this purpose, an impulse lamp fed from an AC network and operating in the standby arc mode and with a flash frequency equal to or a multiple of the network frequency is proposed to include a rectifier forming the duration of the flashes of the lamp and allowing current to pass through it only in the neurodes the time when the mains voltage increases the voltage on the lamp when the current is in standby mode.

FIG. 1 shows the scheme of the proposed device; in fig. 2 - diagrams illustrating his work; pas figs. 3 is a device variant.

The initial ignition of a pulsed gas discharge lamp L (Fng. 1) is carried out by the button K using a high voltage pulse transformer Tr, the primary winding of which discharges capacitor C The current of the pilot arc is maintained by a device including the secondary winding of the transformer Tpz, the rectifier on the diodes D | -D / ,, filter with capacitor Ca and the ballast resistor i. Resistor Ry. prevents shorting of the power source of the pilot arc when pressing the button K.

As is well known, in order to ensure the passage of powerful current pulses through a lamp, it is necessary to periodically supply a voltage from a source of considerable power to it, which is greater than the voltage drop across the lamp at the current of the pilot arc. This function is performed by the secondary winding W of the transformer and the diode Dz operating in the limiter mode.

A voltage is applied to the diode Dj at any time, the difference between the voltage drop on the line at the arc current and the voltage taken from the winding Wz of the transformer Tpz. If, in this case, the amplitude of the voltage Ik (Fig. 2, a) on the secondary winding Wz is in absolute magnitude greater than the voltage drop I.P-lh on la.mpe at the arc duty, then at some moment (L, h) the diode This opens, and through the lamp, the current input is a powerful current discharge (pulse). The discharges end in .moments of time / 2, and, when the voltage Ui on the winding Wl becomes less than the voltage drop on the lamp during the discharge, and the diode Dy closes.

Characteristic changes in the voltage t /; and current / l in the lamp are shown in the fng. 2.6 and 2, c.

Since the internal resistance of the power supply network of the memory is less than the resistance of the lamia, the impulse value of the current is independent of the parameters of the supply network.

No pulses will be equal to twice the frequency of the network.

In a number of cases of impulsive l.n.mensions, the ratio

duration and period of the pulse following (pulse duty cycle). In the proposed device, the duration of ipulses depends on the ratio between the magnitude of the voltage drop across the lamina (The unit rate at the current of the arcing duty and the amplitude of the voltage Itz, removed from the secondary winding Wa of the transformer. At a pulse frequency of 50 Hz time m flashes can be changed from 4 to 7-8 msec; the duration of the pause is

varies from 16 to 12 msec. For a frequency of 0 Hz, the flash time varies in the same range, and the pause varies from 6 to 2 ms.

Practically, due to the fact that the diode D has a non-linear volt-amp characteristic, the duration of the light flashes turns out to be several. (0.5-1 ms).

The ratio t / w. ,,. The pack can be adjusted as a change in the amplitude of the voltage removed from the W-z winding C / "from the winding W-z. , so and change2

voltage drop (Ul. beginning on the lamp when the arc is on duty. In the first case, when the regulation is made by changing the LTOJ (when the type of lamp is selected), the change in the duration of the impulse is inevitably accompanied by a simultaneous change Changes in the magnitude of Ud.iach can be achieved only by changing the meters of the lamna itself.

If the voltage drop / ln. On the lamina at the standby arc current is such that for the lamp to release the rated power, the voltage f / tt-j is equal to the mains voltage (127 or 220 V), the need for a transformer

to provide high current discharges. Then, the entire device, ensuring that .iee passing high-power current pulses through the lamp (not counting the low-power device to maintain the duty arc), is reduced to a single diode (Fig. 3).

Prev Invention

Device for supplying a non-current current to a pulsed gas discharge lamp operating in the stand-by arc mode and with a flash frequency equal to or a multiple of the line frequency, containing initial ignition circuits and maintaining the stand-by arc current that is different in size , weight and increase the reliability of the device, the circuit of the lamp's main electrodes includes a rectifier that forms the duration of the lamp flashes, which ensures that the current through the current lamp only during those periods of time when the network is connected Witzlaus voltage drop across the lamp at a current pilot arc.

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