Clever use of low voltage tester pens
Low-voltage tester is an auxiliary appliance commonly used by electricians. Used to check the conductor below 500V or a variety of electrical equipment shell is charged. An ordinary low-voltage power test pen, can be carried around, as long as the principle of grasping the power test pen, combined with familiar with the principles of electrical engineering, the flexible use of many skills.
(1) determine the alternating current and direct current mnemonic pen to determine AC and DC, AC bright DC dark, AC neon tube through the body bright, DC neon tube bright end. Note: First of all, inform the reader that the use of low-voltage power test pen before, must be confirmed in the charged body test; in the absence of confirmation of the power test pen before normal, shall not be used. Discriminate between AC and DC power, it is best to make a comparison between the "two power", so it is very obvious. Measurement of alternating current neon tube at the same time both ends of the light, measurement of direct current neon tube only one end of the pole light.
(2) determine the positive and negative DC mnemonic: electric pen to determine the positive and negative, observe the neon tube to be careful, the front end of the bright is negative, the back end of the bright for the positive pole. Description: the front end of the neon tube refers to the tip of the pen, neon tube back end refers to the end of the hand, the front end of the bright for the negative pole, and vice versa for the positive pole. Test to focus on: the power supply voltage of 110V and above; if the person and the earth insulation, a hand touching the power supply of any pole, the other hand holding the people's pen, electric pen metal head touched the power supply to be tested on the other pole, neon tube front end of the pole is bright, the power supply of the measurement of the touch is negative; if the neon tube is neon tube back end of the pole is bright, the power supply of the measurement of the touch is positive, which is based on the unidirectional flow of DC and the flow of electrons by the negative to the positive flow of the principle.
(3) determine whether the DC power supply grounded, positive and negative grounding difference mnemonic transformer DC coefficients, electric pen touch does not light; if the light near the pen, the positive pole has a ground fault; if the light is close to the end of the finger, the ground fault in the negative pole. Description: power plants and substations of the DC factor, is insulated to the ground, people stand on the ground, with a power test pen to touch the positive or negative pole, neon tube should not be bright, if bright, then the DC system has a grounding phenomenon; if bright near the end of the tip of the pen, is the positive grounding; if bright near the end of the finger, is the negative grounding.
(4) determine the same phase and different phase mnemonic determine the two lines of the same different, two hands each holding a pen, two feet and the ground phase insulation, two pens each touching a line to be watched with the eyes of a pen, do not light up the same phase bright for different. Note: This test, remember that the two feet and the ground must be insulated. Because most of our country is 380/220V power supply, and transformers generally use the neutral point directly to ground, so do the test, the human body and the earth must be insulated, to avoid constituting a circuit, so as to avoid misjudgment; test, the two pens are bright and do not light up to show the same, so only look at a can be.
(5) determine the 380/220V three-phase three-wire power supply line phase line ground fault mnemonic star-shaped connection three-phase line, the pen touched two bright, the remaining a brightness is weak, the phase conductor has been grounded; if it is almost no light, the metal grounding fault. Description: The secondary side of the power transformer are generally connected to the Y-shaped, three-phase three-wire system in the neutral point is not grounded, with a tester pen touching the three phase line, two than the usual slightly brighter than the other on the brightness to be weaker, it is said that the brightness of this weak phase line grounding phenomenon, but not too serious; if two very bright, and the remaining one is almost invisible bright, it is a metal grounding fault of this phase line.
