Skills and taboos of stage lighting control

When controlling lights, there should be no randomness, because light control has its own operating standards and skills, otherwise, it will cause damage to bulbs, lamps, and light consoles, and even cause fires, causing serious losses. The following are the misoperations that often occur in actual work, which are pointed out here and used as a lesson. 1. When the light bulb is cold, if you turn on the light suddenly (full), the result may cause the light bulb to burst with a "snap" sound; or cause the tungsten filament of the light bulb to fuse.

(1) During the production process of the bulb, the glass shell of the bulb inevitably has uneven thickness, which leads to uneven heating. When the bulb is turned on suddenly, it will cause the glass shell of the bulb to heat up instantly, just like filling an empty glass with boiling water in life. (2) After using the light, the bulb will absorb water molecules in the air during the process of cooling from heat, and these water molecules will stay on the glass shell of the bulb and gather.

When you suddenly push the light bulb on, the water molecules on the glass shell will have the same effect as pouring water into a hot oil pan, and it is only natural for the light bulb to burst. (3) Pushing the light on suddenly will cause an instantaneous inrush current (increase), which will easily melt the tungsten filament of the bulb. Operation skills: When the bulb is in a cold state (before the opening), push up the fader of the console a little (commonly known as the calendering state), so that the light bulb is slightly bright, and let it be in the preheating state, so that It is heated evenly, and at the same time evaporates the water molecules condensed on the glass shell of the bulb. After a few minutes of preheating, push it a little brighter, and after a few minutes of preheating, the light can be fully turned on.

2. Do not turn on the power of the silicon box when the fader of the dimmer is fully pushed. The result is the same as above, except that the bulb will be damaged. All the faders of the dimmer should be turned off, and the power of the silicon box should be turned on.

3. Do not reverse the order of the light console and silicon box power supply when switching equipment. When turning on the power, first turn on the power of the lighting console, and then turn on the power of the silicon box; when turning off the power, first turn off the power of the silicon box, and then turn off the power of the lighting console. If you reverse the order of operations, it will cause all the lights to flicker, which will affect the service life of the bulbs.

4. Do not shake the lamp with big movements when the bulb is turned on. The tungsten filament of the bulb will break or fall off as a result. After the bulb is lit, the temperature gradually rises, and the tungsten wire will become soft accordingly. At the same time, affected by the gravity of the earth, the tungsten wire will also droop accordingly (this phenomenon is especially obvious if the bulb does not use screw-shaped tungsten wire) , At this time, when you shake the lamp with a big movement, you must wait until the lamp is completely cooled before disassembling it.

5. Do not touch the bulb directly with your hands when replacing the bulb, as this will affect the finish of the bulb, and another hidden hazard is the bursting of the bulb. (1) The grease on the fingers or the friction between the fingers and the glass surface of the bulb will leave "scars", which will affect the smoothness and transparency of the bulb and thus affect the normal illuminance of the bulb. (2) If there is sweat on the fingers, the salt molecules in the sweat will absorb the water molecules in the air after the fingers and the light bulb are in "intimate" contact. Once there is water on the light bulb, when the light bulb heats up sharply, it will easily burst.

Operating skills: When replacing the bulb, be sure to wear gloves before touching the bulb. If you don't have gloves, you can wrap the bulb with sponge, plastic paper or soft paper towel before installing. Remember to remove these wrappers after installation to avoid fire when the bulb is turned on. 6. Do not over-focus the speed of light irradiated by the back light.

Too much focus will lighten the colored paper installed on the lamp in a short time, lose its color, and what's more, burn a hole in the colored paper. If the direct distance of the lamp is too close to flammable objects, it is impossible to ignite it. Operation skills: When adjusting the light beam of the lamp, it is better to adjust it to a little astigmatism. If the illumination is not enough, you can supplement the lamp.

7. Don’t forget to install the protective net cover while installing the color changer. The protective net cover is to prevent splashing and hurting people and burning objects when the bulb explodes. Yes, and the outer one is used to install the color changer, and some PAR lamps have fixed protective nets inside, isn't that good? 8. Remember to keep the lamps of the hot light source too "friendly" from the flammable screen. Many years ago, during a performance at a school in Northeast China, it was a tragedy that the lights ignited the curtain and caused a fire, causing hundreds of deaths and injuries. Therefore, it is important to keep a certain distance between the light and the curtain.

The distance between the direct light direction of the 300W lamp and the curtain shall not be less than 3cm, and the distance between the side and tail of the lamp and the curtain (static state) shall not be less than 2m. If the curtain swings a lot, it may be close to the lamp. Set up a metal isolation net between the curtain and the curtain to prevent the curtain from being placed on the lamp and causing a fire. For lamps above 500W, the distance to the direct screen is 5m, and the distance between the side, the tail and the screen is 3m. 9. Do not exceed the power of the installed lights beyond the power specified by the manufacturer.

The power carried by each circuit on the lighting silicon box is described in detail in the manual. Generally, the carrying power of each circuit is 1KW, 2KW, 3KW, 6KW. Take 6KW as an example, the thyristor in the silicon box is also known as solid-state relay is 60A, after calculation, the loadable power is 13.2KW, anyway, there is such a large power space, and lights above 6KW can be installed on this circuit .

The author believes that it is one-sided to only consider the current generated by the bulb at the moment of fusing. Besides, manufacturers will not keep such high-power thyristors for no reason, there is a certain reason for this. Let me talk about an example.

The engineering personnel of a four-star hotel found that a 60W incandescent bulb in the bedside lamp was burnt out while repairing the lamps in the guest room. At the same time, they also found that a 6A fuse that governed the lamp was also blown. Everyone knows , a 60W incandescent light bulb is working at a current of 0.27A, that is to say, the tungsten filament of the 60W light bulb will generate a current of more than 6A at the moment of fusing, and if the plus or minus error of the insurance tube is excluded by 1A, that is to say, the light bulb is blown The instantaneous current is as much as 5 times its working current. The manufacturer of the silicon box designs that the current of the thyristor in each circuit is only 2.2 times the actual carrying current, which is too stingy, so after using the light console for a period of time, you will find that as the bulbs are damaged more, The thyristor in the silicon box is also broken down, and the phenomenon that the light is always on and cannot be turned off or cannot be dimmed is correspondingly increased.

10. Do not cause three-phase unbalance when connecting the load. As we all know, most of the power input to the lighting silicon box is a three-phase four-wire system. When connecting the lighting load to the silicon box, if the lighting load is connected blindly without distribution, it may cause three-phase imbalance.

Then, when the light is pushed brighter, you will feel the difference between light and dark. For example, there is a dimming console with 18 circuits, each circuit carries 6KW of power, the input power is 380V, and its 1-6 circuits are in phase C. Before the load is connected, use a multimeter to measure the voltages of A, B, and C, and the three phase-to-neutral lines are all 220V.

Assume that the 1-6 circuits of the silicon box are connected with a total of 36KW lighting loads, the 7-12 circuits are connected with a total of 18KW lighting loads, and the 13-18 circuits are connected with a total of 6KW lighting loads. In this case, turn on all the lights and measure with a multimeter. The measurement result of A relative to the change is 200V, and the measurement result of C relative to the change is 220V. This is the phenomenon of three-phase imbalance. This phenomenon tells us that the more the load , the more obvious the voltage drop is, the illuminance of the light in one phase with low voltage is obviously lower than that in the one phase with high voltage. Operation skills: the total power of the installed lights divided by 3 is equal to the power allocated to each phase.

Take the power of the above example as an example: 600KW divided by 3 equals 20KW, that is, 1-6, 7-12, 13-18 circuits each load 20KW per phase, so that the three-phase voltage is balanced.