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Switching power adapter quality issues
time2006/09/14
- Everyone knows that the application of the power adapter is very extensive. However, if it is too much, it is easy to "disuse". In order to reduce the cost and cut corners, the power adapter still has quality problems, which is also an important reason for some products to fail.
Everyone knows that the application of power adapters is very extensive. However, if it is too much, it is easy to “disuse”. Because some enterprises lack comprehensive and accurate understanding and understanding of safety standards, and the product structure design is unreasonable, in order to reduce costs and cut corners, There are still quality problems with the power adapter, which is also an important cause of partial product failure. Shenzhen Lianyunda Electronics Co., Ltd. is a professional power adapter manufacturer. Today we will analyze some quality problems of the switching power adapter.
1, the power plug is not standardized:
China's domestic single-phase power plug has two poles without grounding and two poles with grounding. The power plug shown should be able to prevent single pole insertion during use, that is, when any plug of the plug is inserted into the socket of the socket. Other pins cannot be in an accessible state. In the spot check, it was found that the plug was too long, and the excessive length of the plug increased the risk of electric shock during the insertion and removal process. In addition, the shape of the power plug does not meet the requirements and is more common. Because these plugs are not compatible with the sockets used in China, they are also likely to cause electric shock to the user.
2. The mark of the product is incomplete or not standardized:
The mark should contain important information to guide the user to install and use correctly. Marking the product correctly is one of the basic measures to ensure the safety of the user's personal property. The markings are required to be durable and eye-catching. After normal use, the markings should not fall off and the contents should be cleansable. Domestically sold products require the Chinese simplified logo, which should contain at least the following information: the name, trademark or identification mark of the manufacturer or distributor; model code or model specification; power supply properties; rated power supply voltage range. If the information is not complete, it can not correctly guide consumers to use, and some may even misuse and damage the electronic equipment to which it is connected. The common problems are no Chinese logo, no factory name or trademark, model code or model specification.
3. The fever under normal working conditions does not meet the requirements:
The function of the power adapter is to change the voltage. In the process of voltage conversion, a part of the electric energy needs to be consumed due to the loss. After the electric energy is converted into heat energy, part of the heat energy is radiated to the surrounding environment through radiation, convection and conduction, and the other part of the heat energy is itself. Absorbed to raise the temperature of the power adapter. The heat resistance law of the insulating material indicates that the internal temperature of the device rises to a certain temperature, which will lead to rapid aging of the insulating material, shorten the test life of the product, and cause a decrease in safety performance. Therefore, the temperature of the power adapter can only be controlled within the proper range during normal operation to ensure its safe and normal operation. In the supervision and spot check, it was found that under normal working conditions, the temperature rise of the printed circuit board and the transformer winding in the product was too high, and there was a big safety hazard. As a consumer, pay close attention to the temperature rise of the product during use. The simple and easy way is to use the temperature rise of the outer test product shell. The difference between the outer casing temperature of the power adapter and the ambient temperature should not exceed 60 ° C, even in hot weather. In summer, the ambient temperature reaches 35 ° C, and the temperature of the outer casing can't exceed 95 ° C. If the temperature rise of the product is too high, we should stop using it in time.
4. There are hidden dangers of safety performance when the product is short-circuited and overloaded:
In the event of a short circuit in which the output short circuit, capacitor or diode is short-circuited, the internal loss of the power adapter is sharply increased, causing the temperature rise of each part to rise. The design and application of electronic circuits should ensure that under abnormal operating and fault conditions, the temperature rise of each part of the product should not exceed the specified requirements, and the surrounding items must not be exposed to fire hazard. Under the fault conditions, the power adapter can be damaged, but not Reduce the security of your device.
Under the abnormal working and fault conditions, the product does not meet the requirements. It is a common problem in the spot check. Under the fault condition, the product shell temperature exceeds 150 °C, and the shell softens, which seriously reduces the safety performance of the product. The power transformer is a key component in the power adapter and acts as a safety barrier between the primary circuit and the secondary circuit. Therefore, there are strict requirements on the skeleton material and thickness of the transformer and the number of layers of insulating tape to meet the requirements for reinforced insulation between the primary and secondary. Under the fault condition of individual products, the temperature of the winding of the transformer is too high, causing the skeleton to melt.