1、 Test purpose
In order to prevent human body injury, if the following defects occur in the monomer body: loose screws, not locked, parts feet cracked tin, not welded, cold welding and parts feet not inserted into the hole, insulation of transformer and parts is poor or insulation gap distance is not enough, screws or other foreign matters fall into them, function test can not detect abnormal state, From the point of view of protecting product quality and product safety rules, it is necessary to be able to detect these defects. In static state, the above-mentioned defects in the monomer are difficult to find out by testing equipment. Only when the monomer is placed in the vibration system can the above defects be detected by instruments and equipment
2、 Testing principle
1. Hi-pot test < high voltage insulation test >: high voltage is applied to both ends of an object with insulation degree, and whether the insulation between objects meets the requirements of insulation specification can be judged by the leakage current. Here, we short-circuit the Nevral and line of monomer to high-voltage HV terminal, short-circuit the output end and ground wire to return end, add high-voltage, and measure the leakage current, To determine whether the insulation between the input and output terminals and between the input terminal and the ground terminal meets the requirements of Safety specifications,
2. Ground continuity (grounding test): the GND of AC input terminal and the shell of the object to be tested are injected with 25A current. It is measured that the ground wire can not completely contact with the shell, so the measured resistance value will be greater than 0.1 Ω. Only through the ground continuity test can the safety requirements be met,
3. Arcing test (arc test): when the two ends of high voltage are close to each other, there will be a tip discharge phenomenon. This phenomenon may cause great damage to the product after a long time. The more common phenomenon is that when the two ends of the component are to be applied with high voltage, one of the component feet is not welded, but it contacts with the solder joint, and occasionally it will be detached slightly during vibration, Some of the components were scratched by a little discharge,
Arc definition: arc is a physical phenomenon, usually refers to the distance between the two ends, due to insufficient distance or the existence of medium,
However, there is a phenomenon of ignition when it is energized, which is usually discontinuous,
The purpose of arcing detection: the generation of arc will not cause immediate product failure or harm to human body. However, with the increase of use, the insulation between the two ends will be damaged day by day, which will cause machine failure or harm to human body. For example, if the screw of PCB in SPS is locked, the intermediate medium impedance may change after working for a period of time, resulting in floating potential, Therefore, the purpose of arc detection is to take precautions, which can also be called product reliability test,
Principle of arc detection line: in the definition column of arc, arc is discontinuous, and the high-frequency signal of plus or spike above 1kHz is about. Therefore, the principle of arc detection line is as follows:
The current signal from the measured object passes through two loops, one is 20-pass filter and 20-pass field
Hi pass filter is used to convert the current signal into RMS value for measurement and judgment, while hi-pass filter is used for measuring and judging
When arc (high frequency signal) is generated, the low frequency signal is filtered out and only the high frequency signal is left. After measurement and discrimination, the above is the principle of arc detection circuit
Arc function detection calculation: the generation of arc is related to the voltage and distance between the two ends, therefore, the generation of arc
It is usually generated at high voltage, that is, at the wave crest, and the high frequency signal of arc is also carried on the wave crest, so the calculation is carried out
MHP: 0
Example 1:
When testing voltage ac1250vac:
VP = 1250 * √ 2 = 1768v, with resistance 500K Ω as medium
Gap = the distance between the two ends is adjusted to arc, about 0.5mm
Therefore, the arc current is I = V / r = 1768 / 1500k = 3.5map
From the above point of view, it can be calculated by AUM's law, but this is the theoretical value, so we must consider the possibility of various errors, such as
Gap size, resistance and other factors
Arc Level Description:
Grade 9 (0.0027a)
Grade 8 (0.0055a)
Grade 7 (0.0077a)
Grade 6 (0.0100a)
Grade 5 (0.0120a)
Grade 4 (0.0140a)
Grade 3 (0.0160a)
Grade 2 (0.0180a)
Grade 1 (0.0200a)
3. Test equipment:
1. AC with standing voltage tester
2. AC 20W resistance tester
3. Vibration machine
4、 Test items
1. Hi-pot test
2. Arcing test
4. Ground continuity test
5. Insulation (insulation impedance test)
5、 Instrument operation (with reference to 7440)
1. With standing voltage tester, select and press the ac-w key:
W-volt 1500V (input by numeric key)
Hiimit 13mA (enter by numeric key)
Lo-limit 8.0ma
Ramp time 1s
Dweu time 3S
Freqvency 60Hz (set)
Arc sense 8 (set)
Arc fail on (press enter to switch on / off)
Scanner set (not used)
Offset (not set)
Connect on or off (press enter to switch on / off)
Press the "V" key to turn the page up and down, press "enter" to save automatically. For AC or DC, press enter to switch. The setting is the same. For details, please refer to the user's manual
AC  LOW  RESISTANCE  TESTER
First press: grouping and then
Current 25A (set)
CURRENT      25A         (