Ballast use precautions
The basic electrical indicators of the ballast are: starting voltage, working voltage, typical current, output power, cold start current, hot start current, working efficiency, working temperature range, etc.; protection function should have overpressure protection, low voltage protection, and air Load protection, short circuit protection, reverse connection protection, waterproof and vibration proof performance, etc. These technical indicators can generally be measured by some common test instruments, and some indicators require special instruments to test. Here I highlight a few typical data:
First, the ballast cold start time: by looking at the input current, you can easily determine the cold start time of the lamp, and the more accurate method is to test the luminous flux of the HID lamp: a good ballast can make the HID lamp stable in 1 second. 25% of the light is bright, 80% of the stable luminous flux can be achieved in 4 seconds, and the standard below this standard should be carefully selected;
Second, the ballast hot start time: within 15 seconds after the lamp is stable and working, after some stabilizers are energized, the bulb can reach 80% of the highest light in 1 second, almost no delay, and some stabilizers It takes 3-5 seconds to make the bulb reach 80% of the highest light. Of course, the stability of the ballast with less delay is better. When the ballast and the bulb are in normal working condition, you can do the repeated continuous switching action. The good quality ballast generally works normally. Some stabilizers will not be lit properly, and the bulb will have a bright one. It is a big safety hazard for consumers to turn off the power and turn it back on. Invite consumers to pay attention to this when purchasing;
Third, the working mode of the ballast: At present, the ballast works in two ways, namely constant current and constant power, while the latter is the correct design that can provide the long life of HID, a brand new HID bulb, between the electrodes The distance is 4.2mm. In order to generate a lightning arc between the two electrodes (the name is arc), it is necessary to apply 23000V voltage across the electrodes (the operating voltage will drop to 70-100V after lighting), but As the number of lights and time increases, the distance between the two electrodes will become farther and farther, and the operating voltage to maintain the arc jump will gradually increase from 85V to 110V. The constant current ballast will continue to supply a stable operating current, but as the HID tube pressure increases, the overall output power (according to the P=VI formula) will be slowly increased from the rated 35W to 45W. The extra power will accelerate the aging of the HID lamp and reduce the life. Lightly causes the lamp holder to melt down, and the light will burn the lamp or ballast! A stabilizer with a constant power output does not have this concern;
Fourth, the stability of the output power: the characteristics of the HID bulb determines that its working power can only be 35W, too high power will accelerate the aging of the HID lamp and reduce the life. Constant current stabilizers cannot guarantee stable output power. In the fixed power ballast, the stability range of the power of the different schemes is also very different; the stabilizer power error of the analog scheme is about ±3-6W; the power error of the ballast using the single-chip scheme is about ±2- 4W; and the ballast with dedicated chip or built-in DSP core MCU scheme can have an output power error of ±0.5W. It can maximize the life of the HID lamp and closely follow the change of the HID tube pressure so that the HID lamp does not flash and does not go out.
Fifth, the working life of the ballast: in addition to the design factors, the life of the ballast is closely related to the parts used. The most important components are
Capacitance: Electrolytic capacitors must be resistant to high temperature and low leakage, and have a service life of more than 5,000 hours; ignition capacitors are required to continuously withstand high surge voltages.
High voltage package: The high voltage package on the market is roughly divided into two types: wire wound and foil type. In comparison, the foil type high voltage package has more instantaneous output energy, better insulation performance and longer natural life.
Discharge tube: The discharge tube is divided into two types: switch discharge tube and lightning protection tube. The life of the switch discharge tube is more than 10 times that of the lightning protection tube. It may not be good or bad in the early stage of product use, but it is used for a period of time. After that, it is natural to distinguish between good and bad.