Power adapter the analysis of the causes of burn out
Power adapter the analysis of the causes of burn out
The power adapter (
Hereinafter referred to as the power supply)
The nominal voltage and current is what mean?
First of all, the general power supply of the nominal voltage, it is to point to open circuit output voltage, which is not connect any load, outside when no current output voltage, so can also be understood as the voltage is the upper limit of output voltage.
For use inside the power supply under the condition of the active voltage components, even if the mains voltage fluctuation, the output is also a constant value, as the market of small transformers, like the walkman with power supply, if the mains fluctuation, the output of the power supply will not then swings.
In general ordinary real no-load voltage power adapter does not necessarily completely consistent, and nominal voltage because of the characteristics of electronic components can't completely consistent, so there is a certain error, error is smaller, the higher the consistency requirements for electronic components, the production cost is high, so the price is expensive.
In addition, about the nominal current value, regardless of any power supply has a certain amount of resistance, so when the power supply output current, can produce the pressure drop in the internal, lead to two things, one is to generate heat, so the power supply will be hot, another is the results in the decrease of the output voltage, equivalent to the internal consumption.
The power adapter manufacturers have some quality question, mainly: 1.
Non-standard power plug we rule household single-phase grounding power plug pole and the pole and two ways on the ground, as shown in the use of the power plug should be avoid unipolar into, i. e. , when a latch plug socket charged plug set of cooperation other bolt is inaccessible.
Check found that the appearance of the latch, latches is too long to get an electric shock risk to add, in the process of cooperation by the user.
In addition, in the shape of the plug is not in conformity with the applied in our country more see the demand of the plug socket is incomplete, it is a brief electric shock.
Commodity symbols is incomplete or not standard label should include the correct installation, correctly guide the user's important information indicating the commodity symbols, in order to ensure the safety of life and industrial users one of fundamental way.
After use, dazzing, identifying requirements tags should not drop, after normal use, shall be clean and content discernible.
Sale of commodity demand of simplified symbol, should include the following information: less manufacturer or dealer's title, trademark or to identify the symbols, type of code or standard type, nature of the power supply, additional power supply voltage.
If information is not complete, not correctly guide consumers use, some even can damage their misuse and cooperation of electronic equipment, a question, a symbol of our country, the name or trademark, type code or standard.
Normal operation under the condition of heating, do not conform to the requirements of power adapter is a some transform voltage demand amount of power, this is due to the loss in the process of voltage transformation, by radiation, convection, conduction, three cooling mode of electricity is transform into heat, heat of some will be assigned to the surrounding environment, another some absorption of heat, so the temperature rise of the power adapter.
Insulation method, equipment, internal temperature rise to must cause the agile of the insulation aging temperature, shortened life spans of the test, then the function decline of security.
The power adapter, normal operation temperature can only control within a reasonable size, in order to ensure the safety and normal operation ability.
Power adapter under normal operation conditions, when the temperature rise is a high throughout the doubt, as first IT vendors compaq computer company, apple announced that scale, laptop AC adapter, the adapter may be due to the operating temperature, appears briefly, the danger of fire automatic recycling and replace the power adapter on the.
Supervision and check, found that some of the goods under the condition of normal operation, the goods printed circuit board and transformer winding temperature is too high, there is a big security risk.
As a consumer, should close attention to the goods from the temperature rise, brief way is to use the goods from the temperature rise test of shell, power adapter, the temperature difference between the ambient temperature not to surpass 60 ° C, even in the hot summer day, the environment temperature reaches 35 ℃, the shell temperature cannot exceed 95 ° C, if the goods of temperature rise too high, let's stop using immediately.
The analysis of the causes of power adapter burn out 4.
In short circuit and overload safety features dangerous goods under the condition of short circuit fault output short circuit, capacitor or other diode, add the power adapter on the internal loss dramatically, which in some of the rise of temperature rise.
Electronic circuit design and use, shall ensure that under the condition of abnormal operation and fault, the rise of temperature of the commodities of each some can't go beyond the requirements of the rules, and even cannot make items around the fire hazard, power adapter, can damage under fault condition, but you can't drop the function of the safety equipment.
Do not conform to the requirements of goods is not normal operation and fault conditions is a question that in the random check, trouble situation, some shell temperatures above 150 ° C, shell soften the appearance of a serious decline in the function of the safety of the goods.
Power transformer of the key components in the main circuit and assisted circuit safety barrier between the power adapter.
Therefore, the transformer skeleton material and thickness of insulating layer has strict requirements, to meet the needs of reinforced insulation between the primary and secondary.
A single commodity in a fault condition of transformer winding temperature rise too high, cause bone ablation.
Conclusion the rules of the power adapter is 3 c authentication of goods, the existence quality question, mainly is the lack of a full, know and understand the safety standard is one of the company, some other commodity structure design is unreasonable, to cut corners, to drop loss of capital, it is the important cause of some goods.