Product List
Contact Us
Email：qiao@hvtest.cc
Mobile：+8615871365102
What's app：+8615871365102
-
Introduction to Insulation Resistance Measurement
2025-01-09The insulation resistance tester under UHV power can help many power workers conduct various power tests more conveniently.What is a megohmmeter test?A megohmmeter, also known as an insulation resistance meter, is a device used to test the insulation resistance of cables. The test conducted to understand the insulation resistance value is called a megohmmeter test.What is the purpose of insulation resistance?The motor winding wound inside the motor must provide a certain insulation resistance. This insulation is provided to resist high currents in the event of a short circuit. If a conductor has high insulation, its resistance to current will be higher. Similarly, if the provided insulation resistance is weak, it is more likely to cause damage to the equipment due to high current flow. Therefore, in order for any device to function properly, it should have high insulation resistance. Therefore, a megohmmeter insulation resistance test was conducted for this purpose.Procedure for testin
MORE -
Tracking and positioning principles of cable fault tester
2025-01-08The cable fault tester under UHV power can help many power workers conduct various power tests more conveniently.The cable fault tester consists of a transmitter, a receiver, a magnetic induction detection rod, a positioning detection frame, and other equipment. This instrument is a specialized instrument for optical cable and optical cable fault location testing. Suitable for various optical cables and cables with metal conductors (wire pairs, sheaths, shielding layers). The main functions of the street lamp cable fault tester are to locate and test the poor insulation points on the ground, detect the cable path, and test the cable burial depth.1、 Tracer principle (signal method)When an alternating current flows through a conductor, an alternating magnetic field is generated around the conductor, and the magnetic field lines of the field are coaxial with the conductor. At this point, if an electromagnetic coil is placed in a magnetic field, induced voltage will be generated at both en
MORE -
Karl Fischer titration measurement principle for water content
2025-01-08The trace moisture analyzer under UHV power can help many power workers conduct various power tests more conveniently.measuring principle In Karl Fischer moisture content measurement, water reacts with iodine and sulfur dioxide in the presence of alkali and alcohol.[H. sub. 2] O+S [O.sub. 2]+C [H. sub. 3] OH+3 RN+[I.sub. 2] [Right arrow] [RHN] S [O.sub. 4] C [H. sub. 3]+2 [RNH] I (1)In volumetric titration, iodine is added as a titrant.In the Coulomb method, iodine is electrolyzed in an anode solution containing iodine ions.2I - [Right Arrow] [I.sub.2]+2e - (2)As long as there is water in the titration cell, the generated iodine will react according to reaction (1). Once all the water reacts, excess iodine will appear in the anolyte. Iodine was detected by a platinum electrode, and the production of iodine stopped. According to Faraday's law, the amount of iodine produced is proportional to the current produced. In equation (1), [I.sub. 2] and [H. sub. 2] O react with each other in
MORE -
Resonant capacitors and inductors
2025-01-07The series resonance under UHV power can help many power workers conduct various power tests more conveniently.Inductance and capacitance are still two separate components during resonance, otherwise energy exchange cannot occur; But from the perspective of equivalent impedance, it has become a component: a resistor with a value of zero or infinity. In a series circuit composed of resistors, inductors, and capacitors, when the capacitive reactance XC is equal to the inductive reactance XL, i.e. XC=XL, the phase of the voltage U and current I in the circuit are the same, and the circuit exhibits pure resistive behavior. This phenomenon is called series resonance (also known as voltage resonance). When a series resonance occurs in the circuit, the impedance of the circuit Z=√ R2+XC-XL2=R, the total impedance in the circuit is minimized, and the current will reach its maximum value.For ideal L and C components, when series resonance occurs, the voltage on the L and C components is equal i
MORE -
The importance of cable fault locator
2025-01-07The cable fault tester under UHV power can help many power workers conduct various power tests more conveniently.Fault locator is used to identify faults that occur in communication/control cables for quick repair. In order to reduce downtime and facilitate maintenance, cable fault locators are essential. They use the principle of pulse reflection technology to quickly locate the point of fault occurrence, making them very flexible and time-saving. Considering the growth of the telecommunications industry and cable TV operators in the urban, subway, and entertainment industries, the demand for this product is bound to increase.Cable failure is damage to the cable, which can affect the resistance in the cable. If allowed to persist, this may lead to voltage breakdown. Equipment users must use the fastest and most effective method to accurately locate underground cable faults, and the training required for using cable fault locator equipment is minimal. Manufacturers must design equipmen
MORE -
How is series resonance generated?
2025-01-06The series resonance under UHV power can help many power workers conduct various power tests more conveniently.In an AC circuit with resistor R, inductor L, and capacitor C, series resonance generally results in different phases of voltage and current at both ends of the circuit. If we adjust the parameters or power frequency of circuit components (L or C), we can make their phases the same, and the entire circuit appears purely resistive. When a circuit reaches this state, it is called resonance. In the resonant state, the total impedance of the circuit reaches or approximates its maximum value. The purpose of studying resonance is to understand this objective phenomenon and fully utilize its characteristics in science and applied technology, while also preventing the harm it may cause. There are two types of circuit connections: series resonance and parallel resonance. In a series circuit composed of resistors, inductors, and capacitors, when the capacitive reactance XC is equal to t
MORE -
The Karl Fischer titration method that you should know
2025-01-03The trace moisture analyzer under UHV power can help many power workers conduct various power tests more conveniently.In 1935, a German scientist named Karl Fischer made a discovery that provided a new perspective for scientific computing at the time. He found that the sulfur dioxide added to the reaction would determine the water content in the titration. This discovery is today known as the Karl Fischer titration method.What is Karl Fischer titration?Karl Fischer titration is a scientific method used to determine the moisture content in various samples. This concept refers to the titration method involving sulfur dioxide, iodine, and aqueous solutions in the endogenous reaction.In its calculation, Karl Fischer titration involves three main components, namely an analytical balance with a minimum resolution of 0.1 mg, a long syringe with a small needle, and Karl Fischer reagent for determining water content.All components in the instrument must always be placed in an area with constant
MORE -
What factors can affect the test results of the grounding resistance tester
2025-01-03The grounding resistance tester under UHV power can help many power workers conduct various power tests more conveniently.The grounding resistance tester is used to measure the grounding resistance values of various equipment such as power, communication, lightning protection, iron towers, electromechanical, broadcasting and television, buildings, troops, laboratories, workshops, water affairs, large factories, railways, and industries. And departments such as mining enterprises.1) The soil composition around the grounding system (ground grid) is inconsistent, the geology is different, the tightness and dryness are different, and it is dispersed. There are stray currents on the surface, especially overhead ground wires, underground water pipes, cable sheaths, etc. The impact of testing is particularly significant. The solution is to measure at different points and take the average.2) The direction of the test line is incorrect and the distance is not long enough. The solution i
MORE -
Advantages of Karl Fischer method based on measurement
2025-01-02The trace moisture analyzer under UHV power can help many power workers conduct various power tests more conveniently.The moisture analyzer based on Karl Fischer (KF) coulometric titration method utilizes the following advantages to accurately measure trace moisture content (microgram level):The KF reaction exhibits high selectivity towards water; If no side reactions occur, this allows for high-precision measurement of only water.Coulombic titration is an absolute measurement technique that determines the mass of a given substance by measuring the amount of electricity required to electrolyze the substance. It doesn't necessarily require a standard solution.A 1-mA electrolysis current (easily measurable current and duration) flowing for 1 second generates a charge of 1 mC, which is equivalent to only 93.4 ng of water. Therefore, this technology allows for high-sensitivity measurements.Due to these reasons, the KF coulometric titration method is widely used for quality control anal
MORE -
Gas Chromatography Analysis in Transformer Fault Analysis
2025-01-02The oil chromatography analyzer under UHV power can help many power workers conduct various power tests more conveniently.Once a transformer malfunctions, it will have a serious impact on production, causing major power outages and long cycles. Timely understanding of the internal operation of oil immersed transformers and identifying fault symptoms is of great significance for ensuring the safe, reliable, and high-quality operation of transformers. For oil immersed transformers, both the coil and core are immersed in transformer oil. It is impossible to determine the hidden dangers of transformers with naked eyes and direct measurement. A certain technical method must be adopted to understand the operating status of the transformer.Gas chromatography, also known as chromatography, is a physical separation technique. The separation principle is to distribute the components in the mixture between two phases, one is the stationary phase, called the stationary phase, and the other is the
MORE -
Karl Fischer reagent and its reaction
2024-12-31The trace moisture analyzer under UHV power can help many power workers conduct various power tests more conveniently.How would you determine the amount of water in a sample containing trace amounts of water? The method used is Karl Fischer (KF) moisture analysis. The Karl Fischer method uses Karl Fischer reagent to determine the moisture content of a sample, which is a popular method because it allows you to determine the moisture content of a drug in a very fast, accurate, and specific way, and requires a very small sample size for analysis.What is Karl Fischer reagent?The reagent consists of a solvent alcohol (ROH), a known concentration of iodine (I2), a base (RN), and sulfur dioxide (SO2).Reaction principleThe intrinsic reaction of iodine and sulfur dioxide in water systems is based on the Karl Fischer reagent reaction.12+SO2+2H20=>2HI+H2SOThe above reaction was adjusted by Fischer and used to determine the moisture content of substances in non-aqueous systems.When you titrate KF
MORE -
Five points to note in microcomputer relay AC test
2024-12-30The relay protection tester under UHV power can help many power workers conduct various power tests more conveniently.The issues that power workers need to pay attention to when using microprocessor relay protection testers for AC testing are summarized as follows:1. One of the general testing steps for relay protectors is to set the "switch positioning confirmation time". We need to pay attention to setting it larger here, such as around 20ms. If there is a significant error in the test return value, it may be due to the large shaking of the relay contacts. In this case, the test can continue in "manual" mode. To ensure reliable operation of relay protection, it is necessary to ensure that the output of the tester is greater than the starting value of the protection when detecting the relay action time.2. The conventional method for detecting multi-stage overcurrent protection is to test separately in a section and gradually increase the current until the protection is activated. Howe
MORE -
Comprehensive introduction of three types of test frequency ranges in series resonance
2024-12-30The series resonance under UHV power can help many power workers conduct various power tests more conveniently.It is important to select an appropriate testing frequency range based on relevant technical data from both domestic and international sources. There are some different perspectives and formulations in this regard. Based on current domestic and international terminology, we can summarize it into three categories: the first category covers a wide frequency range of 30-300Hz, 20-300Hz, and 1-300Hz; The second category is the power frequency range, 45-65Hz, 45-55Hz; The third category is close to the power frequency, 35-75Hz.1. Wide frequency rangeThe "Test Guidelines" released by the 21st and 9th working groups of the International Conference on Power Grids recommend a frequency range of 30-300Hz. But in reality, even lower frequencies have better equivalence. The draft standards IEC60840 and IEC62067 (2001 and 2000) stipulate that 20-300Hz can be used.Some foreign manufacturers
MORE -
Types of grounding devices and grounding reference resistance values
2024-12-27The grounding resistance tester under UHV power can help many power workers conduct various power tests more conveniently.Types of grounding devices and grounding reference resistance valuesThe electrical installation technical standards specify the following types of grounding installations and grounding resistance values * 1:Grounding installation grounding resistance valueClass A (formerly Class 1) 10 Ω or lessClass B (formerly Class 2) calculated value * 2Class C (old level 3) 10 Ω or lower * 3D-level (old level 3) 100 Ω or lower * 3*1 lists the values of a certain standard.Please note that these values vary by country/region.*2 The ohm value is equal to the ground fault current (ampere) of a wire in the high voltage side or extra high voltage side circuit of a transformer divided by 150 (or, if the voltage of the low voltage circuit exceeds 150 V due to the combination of the low voltage side circuit of the transformer and the high voltage side circuit of the [a] transformer or th
MORE -
Common troubleshooting of series resonance test device
2024-12-27The series resonance under UHV power can help many power workers conduct various power tests more conveniently.1. The fan cannot start:Phenomenon: After emergency stop, fault protection, and mismatch protection, the "fault reset" is not pressed;Reason: High internal temperature, thermal protection of power components;Exclusion method: Turn off the power supply of the instrument, let it stand for about 30 minutes, turn on the power again, press the "Reset" button on the instrument panel, and then restart the instrument.If the fan still cannot be started, please contact our company. The instrument cannot be disassembled!2. Automatic tuning cannot be completed, resonance point cannot be found:Phenomenon: The tuning curve is completely a straight line, and after tuning is completed, the instrument prompts that there is no resonance pointReason: Poor grounding of the circuit, incorrect wiring of the test circuit, and an open circuit in one of the devicesExclusion method: Check the reliabili
MORE -
What is a grounding resistance tester?
2024-12-26The grounding resistance tester under UHV power can help many power workers conduct various power tests more conveniently.What is a grounding resistance tester?The resistance between the grounding electrode and the earth is usually referred to as the grounding resistance. More precisely, grounding resistance is the sum of the resistance of the grounding conductor, the contact resistance between the grounding conductor and the earth, and the earth's resistance. The difference between grounding resistance and ordinary resistance is that it has the following special characteristics:• Polarization effectDue to the fact that the behavior of the earth is similar to that of an electrolyte, it has a polarizing effect, and direct current generates an electromotive force in the opposite direction, making it impossible to measure accurately. Therefore, grounding resistance is usually measured using square or sine waves with frequencies ranging from tens of hertz to 1 kHz.• Special measurement
MORE -
Why does the wave generator of the cable fault locator use audio instead of other frequencies?
2024-12-25The cable fault tester under UHV power can help many power workers conduct various power tests more conveniently.Why does the wave generator of the cable fault locator use audio instead of other frequencies?There are several reasons for using relatively low frequencies.Most cable analyzers use long cables, which may be kilometers or longer. At high frequencies, the attenuation becomes worse with distance. If you want to use pulses with frequency components in the 100MHz range, on most cables, you will not get any significant reflections exceeding a few hundred feet.Other reasons are that it is cheaper, easier to build, and can use less electricity.There is no reason to use a frequency higher than that required to provide the required information on the cable. For cable testers, you would like to know the length and approximate location of the fault. If you want to find the fault within one meter, you need megahertz data. If you only need to know the frequency within 10 meters, you can
MORE -
Guidelines for Karl Fischer titration method for moisture determination
2024-12-25The trace moisture analyzer under UHV power can help many power workers conduct various power tests more conveniently.Karl Fischer titration method for determining moisture contentprinciple:The Karl Fischer titration method is used as a reference method for many substances and is a chemical analysis method based on the oxidation of sulfur dioxide by iodine in methanol hydroxide solution. In principle, the following chemical reactions will occur:H 2 O + I 2 + SO 2 + CH 3 OH + 3RN -> [RNH]SO 4 CH 3 + 2[RNH]ITitration can be carried out by volumetric or potentiometric methods.In the volumetric method, add Karl Fischer solution containing iodine until the first trace of excess iodine appears. The amount of iodine converted is determined by the volume of the burette containing iodine Karl Fischer solution.In the Coulombic method, the iodine involved in the reaction is directly generated in the titration cell through the electrochemical oxidation of iodide, until trace amounts of unreacted i
MORE -
Karl Fischer test method for moisture detection
2024-12-24The trace moisture analyzer under UHV power can help many power workers conduct various power tests more conveniently.Karl Fischer titration (KF) is a technique for determining moisture content. This is a process based on the reaction between iodine and water. The KF method is one of the few techniques that can measure water content without being affected by other volatile substances. The KF titration device can measure free water and bound water, such as surface water on crystals or water inside crystals. This method is applicable to a wide concentration range from 5 ppm to 100% and provides reproducible and accurate results. Our equipment can effectively test various types of solid or liquid samples. The sample size can vary, typically between 0.5-5 grams, depending on the water content in the sample. There are two methods used to perform the Karl Fischer test, the volumetric method and the Coulomb method.Volumetric titration methodVolume titration is used in the range of moisture co
MORE -
Detailed explanation of the advantages of series resonance
2024-12-20The series resonance under UHV power can help many power workers conduct various power tests more conveniently.The development of the power industry now also provides us with a lot of convenience in our lives, especially in providing more electricity, which can be done better in certain aspects. The series resonance test device that people are familiar with now can also appear in people's sight, and because such a device can have many advantages, it can be widely used in various industries.If we understand the advantages of series resonant devices now, we will find several major advantages. The first major advantage is that the required power capacity can be reduced. This experimental device utilizes resonance between reactors and capacitors to obtain voltage and current. Therefore, in the entire system, the power supply only consumes a part of what the system needs, thus reducing power consumption. The second major advantage is that the weight and volume of the equipment have been
MORE
