We often encounter LEDs that don't shine. Package companies, application companies, and the units and individuals that use them are likely to come across. This is the phenomenon of dead lights in the industry. The reason is nothing more than two cases: First, the LED leakage current is too large, causing the PN junction to fail, so that the LED light does not light up, this situation generally does not affect the work of other LED lights; Second, LED lights The internal connection leads are disconnected, causing no current to pass through the LEDs and producing a dead light. This situation will affect the normal operation of other LED lights, because the LED lamp operating voltage is low (red yellow orange LED working voltage 1.8V-2.2V, blue green white LED working voltage 2.8-3.2V), generally used Strings, parallel connections to adapt to different working voltages, the more LED lights in series, the greater the impact, as long as one of the LED lights is connected internally, the whole series of LED lights in the series circuit will not light up. The situation is much more serious than the first case.
LED dead lights are the key to affect product quality and reliability. How to reduce and eliminate dead lights and improve product quality and reliability is a key issue for packaging and application companies. Here are some analysis of some of the causes of the dead lights:
Static electricity causes damage to the LED chip .
Static electricity damages the LED chip, causing the PN junction of the LED chip to fail, and the leakage current is increased. It becomes a resistor. The static electricity is a very harmful devil. The number of electronic components damaged by static electricity all over the world is countless. Ten thousand dollars in economic losses. Therefore, it is an important task in the electronics industry to prevent static electricity from damaging electronic components. LED packaging and application companies should not be taken lightly. Any problem in one link will cause damage to the LED, making the LED performance deteriorate or even fail. We know that the human body (ESD) static electricity can reach about three kilovolts, which can damage the LED chip. In the LED packaging production line, the grounding resistance of all kinds of equipment meets the requirements. This is also very important. Generally, the grounding resistance is 4 Ohm, in some cases where the grounding resistance is even 2 ohms. These requirements are familiar to people in the electronics industry. Whether the key is in place during actual execution and whether there is a record.
It is understood that the general private enterprises, anti-static measures are not in place, this is the test record that most enterprises can not find the grounding resistance, even if the grounding resistance test is done once a year, or once a year, or when there is a problem Check the grounding resistance. It is a very important task to test the grounding resistance test. At least 4 times a year (tested once a quarter), some places with high requirements should be tested for grounding resistance every month.
The soil resistance will vary with the seasons. There are many rains in spring and summer, and the soil wet grounding resistance is easy to reach. In autumn and winter, the soil moisture is less, and the grounding resistance may exceed the specified value. The record is to preserve the original data. It will be well documented in the future. Comply with ISO2000 quality management system. The test grounding resistance can be designed by itself. The grounding resistance test packaging enterprise and the LED application enterprise must do it. Just fill in the various device names in the table and measure the grounding resistance of each device. The tester's signature can be archived.
The human body static electricity is also very harmful to the LED. It should be worn with anti-static clothing when working. It should be equipped with an electrostatic ring. The electrostatic ring should be well grounded. There is an antistatic effect that does not need to be grounded. The antistatic effect is not good. It is recommended not to use the belt. This kind of product, if the staff violates the operating procedures, should receive corresponding warning education, and also play a role in notifying others. The amount of static electricity in the human body is related to the different fabrics worn by people and the physical fitness of each person. It is easy to see the discharge between clothes in the autumn and winter nights. The voltage of this electrostatic discharge is three thousand volts.
Scope of supply
Rating: Up to 200MVA
Voltage:Valve side voltage up to 1000VDC, Grid side voltage up to 220KV
Double star and double bridge
Applications:
The rectifier transformers are mainly used in the electrolysis processes for production of different kind of metals, such as aluminum electrolyzing, magnesium electrolyzing, copper electrolyzing, zinc electrolyzing and other more applications. The largest installed rectifier transformers are always for aluminum electrolysis with some transformer/rectifier combined units in parallel operation to get the required DC current.
Design:
The rectification method is normally known as double star or double bridge. Double star systems use an interphase transformer (IPT) and are usually applied as 6 or 12pulse units where high currents are required with very low nominal voltages. Double bridge system is applied as 6, 12, 24, 48 or 60pulse systems, as required to suit the harmonic mitigation and process stability requirements.
Duty
Electrolysis is normally a continuous process, but with a constant high loading and current harmonics.
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Rectifier Transformer,Bridge Rectifier Transformer,12 Pulse Rectifier Transformer,High Voltage Rectifier Transformer
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