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The pressure and response of LED lighting fixtures

Time:2017-05-22 Views:710
  The setting of leakage current
  The leakage current refers specifically to the leakage current generated in the stress test, which is the value of the alarm valve that we set for the test. The body‘s response to electricity is: the perception of current: 1.1ma, 0.7 mA; Getting rid of the current: 9mA, 6mA (99.5% chance); Fatal current (atrial fibrillation current) : 50mA (current duration over heartbeat), 500mA (duration of current duration within 0.1 second). When the current exceeds 10mA, people are at risk. In general, the current standard for type testing is defined as 5mA. GB 7000.1, type test section is not clearly stipulated stress test the leakage current, in appendix factory pilot testing, specified the size of the value.
  Stress test and breakdown test
  The standard specifies the specific voltage value of the test. The tests show that the insulation structure of the product can withstand the voltage of the test, and it is impossible to say how high the insulation can withstand the voltage. If the application of insulation materials is applied and the design of electrical equipment is required, the test will be tested when the insulation strength is measured. The breakdown test is the voltage when the dielectric is punctured. When the field intensity exceeds a certain limit, the current of the medium is not in accordance with ohm‘s law, but suddenly increases. As shown in figure 1, the insulation is destroyed and the insulation is lost. For electrical products, if the insulation occurs, it loses its operational function.
  Some customer inspection request according to the type of test standards, do a minute test, the product "bring nothing to harm" : first, may reduce the percent of pass of the products; The second, although passing the test, may damage partial insulation structure, make the product safe to reduce; Third, it may damage some components, reduce the quality of the product and shorten the life span. Withstand pressure test passes, does not represent lamps and lanterns is intact. In many cases, LED lights can be tested by pressure-resistant type, but can cause the delay of the lamp, but the life of the lamp will be greatly reduced because of the delay.
  Test method
  Typical pressure testing methods:
  Check to confirm whether the main power switch in the pressure tester is in the "off" position;
  Unless the instrument is specially designed, all non-charged metal parts must be reliably grounded.
  Connect the wires or terminals connected to all the power input of the measuring device.
  4, all power switches, relays, etc.
  5, set the test voltage of the pressure tester to zero.
  Connect the high voltage output line (usually red) to the power input of the measuring device.
  To connect the circuit ground (usually black) of the pressure tester to the uncharged metal part of the measuring device;
  The main power switch of the pressure tester is closed, the secondary voltage of the instrument is slowly raised to the required value, and the rate of lift is not more than 500 V/SEC.
  Maintain the test voltage within the specified time limit;
  Slow down the test voltage;
  Disconnect the voltage tester main power switch. The high voltage output line of the voltage tester is disconnecting, and the ground wire of the test circuit is disconnected.
  The following situation indicates that the test device is not tested:
  1, when the test voltage is not raised to the specified voltage or the voltage is decreased;
  2, the pressure tester has a warning signal.
  It is important to note that because of the high voltage in the stress tests that are dangerous to the person, special care must be taken to carry out the test.
  Special considerations:
  1, it must be stipulated that only those who have been trained and authorized to enter the test area operation instruments;
  A fixed, visible warning sign must be placed around the test area to prevent other personnel from entering the danger zone;
  When testing, all personnel, including operators, must be kept away from testing instruments and equipment.
  Never touch the output line when the instrument is started.
  A common way to improve the ability to withstand pressure
  · adding isolation transformer, which effectively reduces the pressure value of the secondary line through a transformer.
  · increase the strength of the insulating medium, such as glue, and add insulation.
  Improving the ability to withstand pressure on the circuit board: a, the circuit board with high voltage capacity; B, increase the distance of the circuit board.
  As the circuit board where the lamp is lined up, the creepage distance and the wiring space are contradictory. To increase the creepage distance, you can only compress as much space as possible. Try to avoid using sharp objects to reduce the amount of insulation you can break, or withstand pressure from the point of discharge. Try to minimize the use of self-tapping screws; When the circuit board is designed, the right Angle is applied to copper, overprocessing and so on.