【South Guangdong stage lighting network】 light, is the life of television art. Dimming system is safe and reliable, is to use light to shape the objective world of a strong guarantee. Any one of the professional use of the dimming system, the power is very large, a single light bulb is 5kW or even 10kW, and a show can be used thousands of light bulbs. Thus, the total power consumption of a dimming system is staggering. Therefore, the efficiency and cooling of the dimming system is very important, it is the long-term operation of the dimming system to maintain its reliability of the key.

    The dimming device has gone through four generations: the first generation is a resistive dimmer. The second generation of transformer-type dimming equipment. The third generation is the electromagnetic amplifier type dimming equipment. The fourth generation is thyristor dimming equipment. The efficiency of the first generation is the lowest, the fourth generation is the most efficient.

    If the efficiency of the dimming system is not high, the power consumed by itself is considerable. Assuming its efficiency is 96% (it seems to be a very good number), when it wants to push a 6kW load, its own power consumption is already:

    6 × (100% -96%) = 0.24kW

    And assuming that a dimming stand has 60 6kW load, then its total power consumption is as high as:

    0.24 × 60 = 14.4 kW

    Therefore, it is important to improve the efficiency of the dimming system. It not only reduces the temperature rise of the dimmer stand (because the temperature rise and power consumption are proportional), but also reduce the power consumption, thereby reducing operating costs. At present, the more advanced dimming system uses the latest solid switch and efficient.

    Choke, the efficiency of up to 98% or more, reducing the non-100% dimming so that the rapid rise in current generated by the great interference. (The thyristor adjusts the voltage by changing the conduction angle, and its conduction time is only about 1μs. This current waveform is actually a steep pulse with a leading edge.

    However, even a very efficient dimming system, the performance and design of the cooling system is still very important. Even 98% of the efficiency of the above, for example, its own power consumption is still as high as 7.2kW. To such a large power effectively discharged outside the system, to keep the system components within a reasonable temperature environment, the rational design of the cooling system can not be ignored.

    At present, the world's popular counter cabinet cooling system has three kinds: forced air, forced ventilation and intelligent ventilation.

    (1) forced air supply

    The heat dissipation system is to install the blower at the bottom of the stand, so that fresh air from the bottom of the cabinet to enter after the accelerated blowing up, thus taking away the heat generated by thyristor.

    The benefits of this approach are high efficiency, with a small fan can be a lot of heat away. Its drawback is that the cold air drawn from below is continuously heated by the power consumption of the SCR at the top of the flow, so the top of the SCR temperature is much higher than the bottom, resulting in the top of the SCR The reliability and life expectancy decline.

    (2) forced ventilation

    The system is designed to install the exhaust fan at the top of the stand. Through the appropriate process design to make fresh air from the front of each SCR into, and then through the ventilation of the hot air out of the cabinet.

    This method through the precise design (hydrodynamics) and rigorous process control, can be done from the top to the bottom of each thyristor into the air volume are roughly the same, so that each can be a silicon in an acceptable Of the temperature range to run, to ensure the reliability of each SCR. But this design also has shortcomings, is a larger wind resistance, the need to increase the power of the exhaust fan, and thus the noise is also large.

    (3) intelligent ventilation

    Due to the general operating conditions, the dimming system is rarely loaded, so that the required amount of ventilation can be relatively reduced. Intelligent ventilation is based on this theory, by detecting the temperature rise inside the cabinet, and then determine the amount of ventilation in the general operating environment, the fan only low-speed operation, the noise is relatively reduced, but when the load increases, the fan will be correspondingly accelerated. In this way, both to retain the advantages of forced ventilation, but also to solve the shortcomings of high noise.

    Finally, it is worth mentioning that, although there is a high dimming efficiency and good cooling system, but the dimming system is always a great power of the electrical system. High temperature and the emergence of arc ignition and other phenomena can not be completely avoided. Only in the high efficiency and good heat on the basis of supplemented by the necessary anti-high temperature and fire protection measures (such as the use of high temperature flame retardant), can ensure the safe use of the entire dimming system.