(1) to determine the AC and DC formula: Electroprobe judgement AC/DC, alternating bright DC dark, ac neon tube Tongmin bright, DC neon tube bright end.
Note: First of all, to inform the reader that the use of Low-voltage test electroprobe, must be confirmed in the charged body test, not confirmed Electroprobe normal, not to use. Distinguish between AC and DC, it is best to compare the "two power", so it is obvious. When measuring alternating current, the two ends of the neon tube are illuminated at the same time, and only one end of the neon tube is illuminated.
(2) to determine the direct current positive and negative formula: Electroprobe determine positive and negative poles, to observe the neon tube to forestall, the front is bright negative, the back end bright as the positive.
Description: The front end of the neon tube refers to the end of the Electroprobe nib, and the end of the neon tube is the side of the hand. The test should pay attention to: the power supply voltage of 110V and above; one hand to touch the power of any one pole, another hand-held test electroprobe, electroprobe metal head to touch the power of another pole, the front end of the neon tube is very shiny, the contact power is the negative; if the rear end of the neon tube is very shiny, the power supply is positive, This is based on a one-way flow of DC and electrons from the cathode to the cathode flow principle.
(3) Determine whether the DC power source has no grounding and positive and negative pole grounding difference: DC coefficient of the substation, Electroprobe touch does not shine, if light near the tip of the pen, the positive electrode has a grounding fault;
Description: The DC coefficients of power plants and substations are ground insulated, people stand on the ground, with a test electroprobe to reach the positive or negative, neon tube should not be shiny, if shiny, it indicates that the DC system has a grounding phenomenon; If the light is near one end of the tip of the pen, it is the positive electrode grounding;
(4) to determine the same phase and the different phase of the formula: to determine the same difference between the two lines, holding a pen, two feet and the ground phase insulation, two strokes each touch a line, with the eye to watch a pen, not bright with Shangliang for different.
Note: This test, remember that both feet and the ground must be insulated. Because most of our country is 380/220v power supply, and transformers generally use neutral point direct grounding, so do test, the human body and the earth must be insulated between, to avoid the formation of the circuit, so as not to misjudge; When the test, two light and not bright, so only look at one can be.
(5) to determine 380/220v three-phase line power supply line grounding fault formula: Star three-phase line, Electroprobe touched two, the remaining one weak brightness, the phase of the wire has been grounded, if almost no light, metal grounding failure
Note: The two-time power transformers are generally connected to the Y-shaped, in the neutral point ungrounded three-phase system, with the test brush strokes and three phase lines, there are two than usually slightly brighter, and the other one on the weak brightness, it means that this weak phase line has a grounding phenomenon, but not too serious; if two is bright, And the remaining one is almost invisible light, it is the phase line has metal grounding fault.