Light is the life of television art. The safety and reliability of the dimming system is a strong guarantee for using light to shape the objective world. Any professional dimming system, its power is very large, a single bulb is 5kW or even 10kW, and a performance can use thousands of bulbs. It can be seen that the total power consumption of a dimming system is staggering. Therefore, the efficiency and heat dissipation of the dimming system are very important, which is the key to maintaining the reliability of the dimming system for a long time.

Dimming equipment has gone through four generations: the first generation is a resistive dimmer. The second generation is transformer-type dimming equipment. The third generation is electromagnetic amplifier type dimming equipment. The fourth generation is a thyristor dimming device. 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 its efficiency is 96% (which already seems like a very good number), when it is going to push a 6kW load, its own power consumption is already as:

6×（100%－96%）=0.24kW

Suppose a dimming 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 cabinet (because the temperature rise is proportional to power consumption), but also reduces power consumption, thereby reducing operating costs. At present, the most advanced dimming systems use the latest solid switches and high efficiency.

The choke, with an efficiency of more than 98%, reduces the great interference caused by the sharp rise in current due to non-100% dimming. (The thyristor adjusts the voltage by changing the conduction angle, and its on-time is only about 1μs, and this current waveform is actually a sharp pulse with a sharp edge.) ）

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

At present, there are 3 kinds of popular cabinet cooling systems in the world: forced air supply, forced exhaust and intelligent exhaust.

(1) Forced air supply

This heat dissipation system is to install the blower at the bottom of the cabinet, so that fresh air enters from the bottom of the cabinet and accelerates upward, thereby taking away the heat generated by the thyristor.

The advantage of this approach is that it is efficient, and a large amount of tropics can be carried away with a small fan. Its disadvantage is that the cold air pumped in from below is constantly heated by the power consumption of the thyristor on the way up, so the temperature of the thyristor at the top is much higher than that of the bottom, resulting in the reliability and life of the thyristor at the top.

(2) Forced convulsion

The system is designed to mount the exhaust fan on top of the cabinet. Through proper process design, fresh air enters from the front of each thyristor and then exhausts the hot air outside the cabinet.

Through precision design (fluid dynamics) and rigorous process control, this method can achieve approximately the same air intake volume for each thyristor from top to bottom, so that each thyristor can operate within an acceptable temperature range, ensuring the reliability of each thyristor. However, this design also has disadvantages, that is, the wind resistance is large, and the power of the exhaust fan needs to be increased, so the noise is also large.

(3) Intelligent exhaust

Since the dimming system is rarely fully loaded under normal operating conditions, the required exhaust air volume can be relatively reduced. Intelligent exhaust is according to this theory, by detecting the temperature rise in the cabinet, and then determining the exhaust air volume, in the general operating environment the fan only needs to run at low speed, the noise is relatively reduced, but when the load increases, the fan accelerates accordingly. In this way, the advantages of forced exhaustion are retained, and the disadvantages of high noise are solved at the same time.

Finally, it is worth mentioning that although it has high dimming efficiency and a good heat dissipation system, the dimming system is always a very powerful electrical system. High temperatures and arc ignition are impossible to completely avoid. Only on the basis of high efficiency and good heat dissipation, supplemented by necessary anti-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 ensured.