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Edit: GTG 2021-12-30 116
Power supply products are widely used, and basic electronic products need to use various power supply products; whether power supply products are circulated alone or installed on various electronic products for circulation, corresponding safety tests are required, that is, power supply people often Said safety test! The following editor interprets the items of power product safety testing:
1. High-voltage test
High-voltage test is a required test item required by international safety certification bodies. The product must be tested in percentage before leaving the factory. , is an indicator of quality assurance and electrical safety. The test method is to add an abnormal
voltage to the product for testing, and this voltage must last for a period of time. Finally, it is determined that as long as there is no insulation breakdown, that is Can be considered to pass this test.
Insulation resistance test
Insulation resistance applies a DC voltage to two related points, up to 1000 volts, and the unit is usually ohms, which can determine good and bad products.
3. Ground impedance test
The ground impedance test is to test the ground point of the product. Apply a constant current power supply to the shell or metal part of the product to test the impedance between the two points. Generally, the product requires a test of 25 amps, and the impedance should not be greater than 0.1 ohm. The CSA requires a 40-amp
test, which can detect problems such as the grounding point screw is not locked, the grounding wire diameter is too small, and the grounding line is open circuited.
4. Leakage current test
refers to the current that flows through the metal contactable part of the equipment to the grounded part or the accessible part through the human body when the equipment supplies current.
Input test The purpose of the safety input test is to examine whether the input meets the requirements of the product when the product is working normally, and whether the input circuit can withstand the current required by the product when it is working. It is stipulated in the product standard that the input current of the maximum power consumption cannot be greater than 110% of the nominal value of the product. This nominal value also tells the user the minimum current required for the product to work safely, so that the user should prepare such an electrical environment before using the device.
6. Stability test of safety signs
The warning signs for user safety must be stable and reliable, and cannot be used for a period of time because they become blurred, which leads to wrong use by users, which leads to danger, or directly leads to danger. So this stability needs to be tested. In the safety standard, it is stipulated that: test 15S with water, and then test 15S with petroleum spirit, and the logo should not be blurred.
7. Capacitor discharge test
For a device with a pluggable power cord, the power cord is often pulled out of the socket, and the power plug of the socket is pulled out, often being played with or placed arbitrarily. This leads to a problem. The power plug is charged when it is pulled out, and this power disappears with time. If the time is too long, it will cause electric shock to the person playing with the plug, and damage to other equipment if the power plug is placed arbitrarily. or the device itself. Therefore, various safety standards for the whole machine make strict regulations on this time. We design products to consider this time, and the product safety certification needs to measure this time.
8. The circuit stability test
SELV circuit is the safe ground voltage circuit. Note: SELV circuits have different interpretations in different standards. For example, the interpretation in IEC60364 is different from IEC60950-1. Therefore, it is necessary to pay attention to which standard SELV is under, and its dangers are also different.
9. Limited power source circuit
Because the output power of the limited power source circuit is very small, in the known experience, they will not cause the danger of fire, so in the safety standard, the shell of this type of circuit has been specially reduced. Their flame rating is UL94V-2. Therefore, all such circuits need to be measured to prove that they are limited power source circuits.
10. Current limiting source circuit
There is this regulation in the safety standard, and this regulation is the current limiting source circuit. Current-limiting source current requires that under normal circuit and single fault, the outgoing current is below the safety limit, and it will not cause danger to people and be less than 0.25mA. Resistors for isolating primary and secondary circuits are shock-resistant resistors that are required to meet specific standards.
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