Light is the life of TV art. The safety and reliability of the dimming system is a powerful guarantee for using light to shape the objective world. The power of any professional dimming system is very large. A single light bulb is 5kW or even 10kW, and a performance can use thousands of light bulbs. This shows that the total power consumption of a dimming system is amazing. Therefore, the efficiency and heat dissipation of the dimming system are very important. It is the key to maintaining the reliability of the dimming system for a long time.

    There are four generations of dimming equipment: the first generation is a resistive dimmer. The second generation is transformer-type dimming equipment. The third generation is an electromagnetic amplifier type dimming device. The fourth generation is SCR dimming equipment. The first generation has the lowest efficiency, and the fourth generation has the highest efficiency.

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

    6 × （100% －96%） = 0.24kW

    Also assume that a dimming vertical cabinet has 60 loads of 6kW, at this time, its total power consumption is as high as:

    0.24 × 60 = 14.4kW

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

    The choke coil has an efficiency as high as 98% or more, which reduces the great interference caused by the rapid rise of the current due to non-100% dimming. (The thyristor adjusts the voltage by changing the conduction angle. Its conduction time is only about 1μs. This current waveform is actually a pulse with a steep front.)

    However, even for a very efficient dimming system, the performance and design of the heat dissipation system is still very important. Even with an efficiency of 98%, taking the above example as an example, its own power consumption is still as high as 7.2kW. To effectively discharge such large power consumption out of the system and keep the internal components of the system working in a reasonable temperature environment, the rational design of the heat dissipation system cannot be ignored.

    At present, there are three kinds of popular cabinet cooling systems in the world: forced air supply, forced air extraction and intelligent air extraction.

    (1) Forced air supply

    This heat dissipation system is to install the blower on the bottom of the vertical cabinet, so that the fresh air enters the bottom of the vertical cabinet and accelerates to blow up, thereby taking away the heat generated by the thyristor.

    The advantage of this method is high efficiency, a small fan can take a lot of tropical. Its disadvantage is that the cold air drawn from below is continuously heated by the power consumption of the thyristor during the upward flow, so the temperature of the thyristor on the top is much higher than that of the bottom, resulting in the thyristor on the top The reliability and lifespan of the system are reduced.

    (2) Forced ventilation

    The design of this system is to install the exhaust fan on top of the cabinet. Through proper process design, make fresh air enter from the front of each thyristor, and then exhaust the hot air to the outside of the cabinet through the exhaust air.

    This method through precise design (fluid dynamics) and rigorous process control, can achieve the same air intake from the top to the bottom of each thyristor, so that each thyristor can be acceptable Operates within the temperature range of each other, ensuring the reliability of each thyristor. However, this design also has the disadvantage that the wind resistance is large, and the power of the exhaust fan needs to be increased, so the noise is also large.

    (3) Smart ventilation

    Under normal operating conditions, the dimming system is rarely fully loaded, so that the required amount of ventilation can be relatively reduced. Smart extraction is based on this theory, by detecting the temperature rise in the cabinet and then determining the amount of extraction. Under normal operating conditions, the fan only needs to run at a low speed, the noise is relatively reduced, but when the load increases, the fan will accelerate accordingly. In this way, not only the advantages of forced ventilation are retained, but also the shortcomings of high noise are solved.

    Finally, it is worth mentioning that, despite the high dimming efficiency and good heat dissipation system, the dimming system is always a very powerful electrical system. Phenomenon such as high temperature and arc fire can not be completely avoided. Only on the basis of high efficiency and good heat dissipation, supplemented by the necessary high temperature and fire prevention measures (such as the use of high temperature flame retardant wire), can the safe use of the entire dimming system be guaranteed.