Using facts to prove that thyristor to dimming energy is just a rumor

Xu Qinghui

Yun Zhiguang Co-founder & Chief Product Officer Guangdong Provincial Optoelectronics Technology Association Expert Committee Secretary Fudan University Lighting & Lighting Engineering Senior Lighting Designer China Lighting Association Interior Lighting Professional Committee Member China Association of Lighting Designers (CLDA) Vice President Senior DIAL Global Certified Instructor 20 years of industry experience as a senior lighting engineer

SCR dimmer is currently the mainstream equipment in the field of stage lighting and environmental lighting. The use of thyristor dimming technology, matching the installation is relatively simple, only need to replace the LED lamps. Therefore, thyristor dimmers are widely used in incandescent lamps and other traditional lighting markets. They not only meet people's usage habits, but also have low dimming costs and are compatible with existing lines without rewiring.

In general, the various dimmers used in the lighting system are essentially an AC voltage regulator. Older transformers and varistor dimming are achieved by adjusting the voltage or current amplitude. Compared with transformers and resistors, SCR dimmers have completely different dimming mechanisms. They use phase control methods to achieve voltage regulation or dimming.

However, in the industry there is such a rumor that using a phase-cut to dim, but the brightness of the light bulb is reduced, but in the dimmer will consume more power, so SCR dimming is actually not energy-saving.

So, is that true? No, dimming by thyristor can also save energy. Let's verify this with experiments.

Experiment content: Through the use of thyristor dimmers to adjust the brightness of different light sources, observe whether the total power of the entire system has decreased, to explore in the end SCR dimming energy can not save energy.

Incandescent light bulbs

First, we set the brightness of the incandescent bulb to its brightest, and the power meter reading was 39.8 W. Since the power meter is connected to the entire system, its reading is the total input power of the entire system.

Then we slowly dim the bulb's brightness. It can be seen that the reading on the power meter gradually becomes smaller as the brightness becomes darker.

This shows that while dimming the bulb, the total power of the entire system will also drop, and the rumor will not break.

Some people may also say that only incandescent light bulbs can save energy. Then, let's try another light source by replacing it.

Quartz lamp cup

Using a quartz lamp cup coupled with an Opto's traditional engineering dimming electronic transformer, and then repeating the above experiment, what would be the result?

The quartz lamp cup is adjusted to the brightest, and the figure displayed on the power meter is 43.1 W. As the brightness of the quartz lamp cup is gradually darkened, the power is gradually declining.

When the filament has only a trace of red light, the power is 5.79W at this time, and it can be seen that using a thyristor dimmer to dim the lamp cup can also save energy.

LED light cup

If you use the same dimming electronic transformer, but the light source is replaced with Philips LED lamp cup? We still adjust the brightness of the lamp cup to the brightest. At this time, the power is 7.34W.

When brightness modulation was barely visible to the naked eye, the power was reduced to 0.55W.

Phase-dimmable lamp band driver

We then use the Oches 24V phase-cut dimming driver and connect it to a 24V strip for testing. Adjust the light bar to the brightest, with a power of 11.4W.

Dim the light bar gradually and the power can be reduced to 1.67W.

in conclusion

Through the above experiments, it can be found whether the incandescent lamp is dimmed directly by phase cutting, or the dimming transformer is used to dim the lamp cup, or the dedicated lamp dimming driver is used to adjust the lamp band and the spot lamp. Light, can make the total power of the entire system drop, so as to achieve the purpose of energy saving.

Therefore, the use of SCR to dimming is not just a rumor, it turns out that phase-cut dimming can save energy!