NOYAFA's Non-contact Voltage Detector

NOYAFA's Non-contact Voltage Detector

2021-11-09
NOYAFA
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non-contact voltage detector is formulated and designed after years of efforts that SHENZHEN NOYAFA ELECTRONIC CO.,LIMITED make. The product is the result of our company's hard work and constant improvement. It can be observed for its unparalleledly innovative design and delicate layout, for which the product has been widely acknowledged and received by a massive amount of customers who has a great taste.Our dedication to delivering preferred NOYAFA is what we are always doing. To build strong and long-lasting relationships with customers and help them achieve profitable growth, we have enhanced our expertise in manufacturing and built exceptional sales network. We expand our brand by enhancing the influence of 'Chinese Quality' in the global market - so far, we have demonstrated the 'Chinese Quality' by providing the highest quality product to customers.We maintain a distribution network of non-contact voltage detector and other products of Best Cable Tester Supplier in China _ Noyafa throughout most parts of the world and consistently expand staff of devoted sales representatives to compensate for the growing geographic market area.
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Does Fiber Optic Testing Procedure Have Warranty Period?
Does Fiber Optic Testing Procedure Have Warranty Period?
Yes, NOYAFA provides warranty service for fiber optic testing procedure. Being a quality-oriented company, we warrant our products against defects in materials and workmanship. In general, under normal use and service, every portion of the product will be free from physical defects during the warranty period. However, once there is something wrong with the product, it will be repaired or replaced as determined solely by us. We provide a limited warranty for our products only to the person or entity that originally purchased the product from us or our authorized distributors or retailers.SHENZHEN NOYAFA ELECTRONIC CO.,LIMITED is an expert in manufacturing fiber optic testing procedure. Being distinctly superior in fiber optic testing procedure, our products gain more and more popularity. You give trust our fiber optic testing procedure and we will give good quality in return.We pledge our best efforts to make your experience both beneficial and enjoyable. Check it!· Related Questions:1. How long is the warranty period of fiber optic testing procedure?At NOYAFA, every provided product comes with a certain period of warranty. We offer warranty service for any quality problems of our products within a selected period of time. You can see the specific warranty period from product information on our website. If there is no such information provided on our website, please consult us. During the warranty period, we can offer return/replacement service for products of any quality problems. Please be confident to buy from us. A high level of quality and service is our commitment. ——————— 2. How to extend fiber optic testing procedure warranty?NOYAFA gives customers the option to extend the warranty of fiber optic testing procedure. In this way, we hope our customers will feel more comfortable with their orders. But please note that from Chinese manufacturers, the warranty cost is usually included in the price of the product whereas an extended warranty costs extra and is sold separately. You shall consider whether the product will require repair and the possible cost of such repairs. It is suggested that customers make a decision at the time of purchase, or within a few more days or weeks to return to us and purchase the extension.
Brief Introduction of Intelligent Handheld Cable Tester
Brief Introduction of Intelligent Handheld Cable Tester
Intelligent handheld cable tester Handheld cable tester generally adopts pulse reflection method. Judge the fault point according to the returned waveform. The waveform returned during each test will be different due to some external reasons. Therefore, the requirements for the working experience of users are relatively high. In view of this situation, TFN launched an intelligent handheld cable fault tester. The intelligent handheld cable fault tester is equipped with AGC (digital gain automatic control) system; Digital waveform automatic recognition technology; ARM CPU with FPGA technology. The machine automatically recognizes the waveform and judges the fault point. There is also waveform comparison function, which can make you learn waveform recognition faster. Instrument introduction: D131 series cable fault obstruction intelligent rangefinder is suitable for automatically measuring the precise position of core wire obstacles such as broken wire, mixed wire and ground gas of power cable and communication cable. The d131 series is characterized in that it can automatically test many typical faults. The specific features are as follows: 1) DAGC (digital gain automatic control) system: digitally adjustable gain. Eliminate the waveform distortion of the original instrument of the same type due to the potentiometer knob. It can also be used for pure linear adjustment, which is conducive to manual testing. 2) Digital waveform automatic recognition technology: rely on the machine to automatically recognize the waveform that is difficult to judge manually. 3) Using ARM CPU and FPGA technology, it can quickly carry out various complex operations and accurately judge the fault waveform. 4) Waveform comparison function is convenient to compare the test waveforms of fault line and normal line, and clearly locate the fault point. 5) Large screen color LCD display, humanized interface menu design, fast digital buttons, convenient for users to operate. 6) High energy lithium battery can be used for up to ten hours (charging with a special charger). 7) Wave speed memory, power on after power off, and the wave speed is automatically set to the wave speed at the last power off. fqj
Why You Want a Cable Length Testers
Why You Want a Cable Length Testers
Today there are many different manufacturers and types of network cable testers on the market. Standard testers are used by those who want to check the quality of their cables. Bridge cables are a one-piece technology and are often used by certification testers as they can perform a greater variety of tests and there are short training videos on how to use them.Professional network testers are used in commercial environments and by certified professional cable installers at work. Professional testers have more skills when it comes to troubleshooting cables while maintaining a high level of accuracy. As an added bonus, professional testers allow you to track and archive your test results for future references.Some verification tools contain additional features such as a Time Domain Reflectometer (TDR) to determine the length of the cable and the distance between interruptions and short circuits. Some test tools do not provide information about bandwidth or suitability for high-speed data communication.There are many different types of network testers on the market today. LinkIQ cable network testers are easy to use, as explains Eric Webb, Fluke Network Product Manager in the video below. It shows how the settings can be used to perform a cable test with a network cable tester, save the results and upload them to link ware where they are available.To help you find the best network or cable tester for your use, I have compiled a list of test products that work well. The most obvious difference between a generic or standard tester and a professional tester is the brand cost, where professional network testers are more expensive than other testers.I came across the Elegiant Network Cable Tester while working on establishing a LAN connection for a local company. With my extensive experience as an electrician, I can say that this is the best tool for testing cable connections.Selecting, selecting and purchasing a suitable network cable tester can be a complicated and challenging task. However, there are some essential factors that consumers should consider when purchasing a good network cable tester and absolutely should consider, as they can make or break the tester you are buying.For example, suppose you are looking for a good Ethernet cable tester or Ethernet cable speed tester. Network cable testers are sensitive products that are exposed to various extreme elements, suggesting that you should get a tester with a long warranty. In this case, you should look at the reviews of the Ethernet cable testers from previous buyers, who can confirm the star rating of the products.These three basic tests are performed in accordance with the EIA standards for twisted pair cables, wire mapping and cable length for high-speed performance. Check that the signal is strong and fast enough to meet network performance requirements. If you are testing the cable length with a calibrated capacitive tester it is better to test with a time domain reflector tester, as it can measure the distance to the location where the error is displayed.Make sure that the two ends of the cable you want to test are not connected to a TV, cable distributor, or any other related device. Find the right cable and touch the cable to one or the other so that a beep is generated. Connect one end of the coaxial cable tester to the wall plate on your coaxial cable wall and point the other end to the tester so that the entire cable can be assembled.This situation is indistinguishable from a real insulation break when the triggering current is exceeded. As the length of the cable increases, its capacity is limited by the rise time. The shorter the rise time, the higher the voltage, and the larger the DV / DT, the greater the amount of current required to charge the cable (parasitic capacity). Increasing the wire resistance of a longer cable helps to slow the charging current but requires a minimum dwell time of 10 s to ensure that the full cable length is reached before the test voltage is performed (leak measurements).Dirty contacts, bad bruising, cable damage and poor quality can provide strange and wonderful reading results. In order to reach the test voltage without damaging the traction current, it should be taken care to adjust the voltage ramp to the length of the cable so that it slows down. Cami Research ramp tester has a ramp which can be adjusted from 150 V / s to 5,000 V / s.The flagship cable tester VDV-II Pro uses a TDR to measure cable length and provide distance and error information. A TDR works by injecting a signal into the cable and measuring the time the signal reflects an impedance change caused by a short circuit.Standard testers are manual, while professional testers work automatically. Automatic testers allow you to apply contrasting IA- and ISO-testing methods and highlight many individual tests to verify conformity.The PocketHornet comes standard with a limited warranty of 1-2 years, depending on the region. Customers in the EU receive a 2-year warranty, while others only receive a 1-year warranty. It is not a cable certification device, but conducts cable qualification and verification.There are various types of cables on the market, but the most popular and widely used cable for modern technology is the coaxial cable. This article describes how to test a coaxial cable signal with a multimeter in situations where the transmitter does not work well. We may receive a small commission if you purchase a product through our selected links but the price of the product remains the same.In a house with a wired network connected to the TV, the cable coming from the family room should connect to a cable modem or router upstairs. There are 2 cables in the family rooms, the one marked "upstairs" is connected to the office upstairs and the other "downstairs" to the basement.
How Does the Doctors Screwdriver Run a Calculation Whilst Destroyed?
How Does the Doctors Screwdriver Run a Calculation Whilst Destroyed?
In The Almost People, and The Eleventh Hour, the Doctor's screwdriver is destroyed and later regenerated. However, in The Day of the Doctor, the Doctor(s), run a calculation running over 400 years. How is this possible, if the screwdriver was destroyed between the start and finish? This is technically trivial. Anyone running a very long computation (and some real computations can last for weeks) will regularly save the state of the computation on some reliable medium that does not need power, so that the computation can be restarted after any kind of failure. Actually there can even be several levels of back-up, balancing reliability and cost.The computation does not need to be restarted with exactly the same software, as long as the intermediate results that have been saved can be interpreted and reused by the new software. Actually this can even be a way to improve the software (or the hardware) while the computation is on-going. This is standard technology, even for people who are not time-lords.The screwdriver could simply save its state on the Tardis whenever there are close enough to communicate by whatever means. It could also be saved in various places known to be stable in time by someone who travels through time.If the screwdriver is destroyed, only that part of the computation done since the last back-up is lost and must be redone.By the way, since the Doctor travels through time, he could well organize the computation and back-up to get a lot more than 400 years worth of computation, depending on the structure of the algorithm and the computational capacity of the screwdriver.It is to be expected that the computation does not take all the computational power of the screwdriver. If a computational thread actually leaves a lot of untapped computational power, it can be parallelized with a future fragment of the same thread by getting from the future the starting state for the later thread. Time travel extends the possibilities for parallelizing computations. OTHER ANSWER: Like Rose said in The Day of The Doctor" Same Software different case"Therefore the Doctor's screwdriver was not completely destroyed, only the case containing it was; the software was safe making it possible for the TARDIS to repair the case and give the Doctor a seemingly "new" screwdriver with the computation still intact
Working Principle of Cable Fault Tester
Working Principle of Cable Fault Tester
Working principle of power cable fault tester consists of three main parts: power cable fault tester host, cable fault locator and cable path tester. The host of the cable fault tester is used to measure the nature and total length of the cable fault and the approximate position between the cable fault point and the test end. The cable fault locator determines the exact location of the cable fault point based on the approximate location of the cable fault point determined by the host of the cable fault tester. For buried cables with unknown direction, a pathfinder shall be used to determine the underground direction of the cable. The basic method of power cable fault test is to apply high-voltage pulse to the fault power cable to produce breakdown at the cable fault point. When the cable fault breakdown point discharges, it generates electromagnetic wave and sound at the same time. The working principle of the application of arc reflection method (secondary pulse method) in cable fault location: firstly, a high voltage pulse with a certain voltage level and energy is applied to the faulty cable at the test end of the cable to make the high resistance fault point of the cable break down and burn arc. At the same time, add the low-voltage pulse for measurement at the test end. When the measurement pulse reaches the high resistance fault point of the cable, it encounters an arc and reflects on the surface of the arc. When arcing, the high resistance fault becomes an instantaneous short-circuit fault, and the low-voltage measurement pulse will change obviously in impedance characteristics, so that the waveform of flashover measurement becomes a low-voltage pulse short-circuit waveform, making the waveform discrimination particularly simple and clear. This is what we call the "secondary pulse method". The received low-voltage pulse reflection waveform is equivalent to the waveform of a wire core completely short circuited to ground. Superimpose the low-voltage pulse waveform obtained when releasing the high-voltage pulse and when not releasing the high-voltage pulse. The two waveforms will have a divergence point, which is the reflected waveform point of the fault point. This method combines low-voltage pulse method with high-voltage flashover technology, which makes it easier for testers to judge the location of fault point. Compared with the traditional test methods, the advantage of the secondary pulse method is to simplify the complex waveform in the impulse high-voltage flashover method into the simplest low-voltage pulse short-circuit fault waveform, so the interpretation is very simple and the fault distance can be accurately calibrated. The triple pulse method adopts the double impact method to prolong the arc burning time and stabilize the arc, which can easily locate the high resistance fault and flashover fault. The triple pulse method has advanced technology, simple operation, clear waveform and fast and accurate positioning. At present, it has become the mainstream positioning method of high resistance fault and flashover fault. The third pulse method is an upgrade of the second pulse method. The method is to first measure the reflected waveform of the low-voltage pulse without breaking through the fault point of the measured cable, then impact the fault point of the cable with the high-voltage pulse to generate an arc, trigger the medium voltage pulse when the arc voltage drops to a certain value to stabilize and prolong the arc time, and then send the low-voltage pulse, Thus, the reflected waveform of the fault point is obtained. After the superposition of the two waveforms, it can also be found that the divergence point is the corresponding position of the fault point. Because the medium voltage pulse is used to stabilize and prolong the arc time, it is easier to obtain the fault point waveform than the secondary pulse method. Compared with the secondary pulse method, the triple pulse method does not need to select the synchronization time of arc burning, and the operation is also more simple.
Introduction of Test Composition of Live Cable Fault Tester
Introduction of Test Composition of Live Cable Fault Tester
Cable fault tester is a commonly used cable fault detection equipment. This equipment is used with a variety of cable fault detection. Its stable performance and accurate detection make the cable fault detection more comprehensive. The work efficiency of inspectors has been greatly improved. Today we mainly explore the composition of live cable fault tester. Test composition of live cable fault tester: 1. Live cable fault tester is composed of the following parts: 1. Instrument host: cable fault flashover tester, referred to as flashover tester for short. Cable path test signal source, referred to as path tester. Cable fault point / path meter receiver, referred to as point meter. 2. High voltage accessories: high voltage pulse capacitor. The utility model relates to an AC / DC dual-purpose high-voltage test transformer. High voltage test transformer operation box. 2、 The test functions of the cable fault tester mainly include: 1. Purpose: it is suitable for low resistance fault test, short circuit fault test, open circuit fault test, high resistance leakage fault test and high resistance flashover fault test of various power cables with different sections and media, high frequency coaxial cables, municipal cables, street lamp cables, ground buried wires, etc. Specifically, there are the following types: (1) testable cables are equivalent according to voltage: low voltage cables and high voltage cables. (2) Testable cables can be divided into: power transmission cables; Control cable; Street lamp cable. (3) The testable cables can be divided into: directly buried cables, cables laid in cable trenches, overhead cables and more than two parallel directly buried low-voltage wires. (4) Testable cables can be divided into: short circuit fault; Phase failure; Low resistance fault; High resistance leakage fault; High resistance flashover fault is described in detail after fault classification. (5) If there is a cable identifier, we can find the cable we are looking for from multiple cables buried in the cable trench, that is, the cable identifier. (6) Both fault test and cable identification are conducted for power-off cables, and fault test cannot be conducted for live running cables. 3、 Introduction to the test principle of cable fault tester: 1. The host of this set of instrument is a host, which is mainly used for cable fault test. 2. It is a rough measuring instrument for cable fault distance, which can measure the approximate distance from the fault point to the cable test end face. 3. The lightning meter can measure the cable length and the propagation velocity of electromagnetic wave in the cable. The test principle of lightning meter is radar reflection method, also known as pulse reflection method. Single end test distance of lightning meter: 15km. Minimum test distance (blind area) of lightning meter: 15-20m. 4. Measurement error of cable fault tester: rough measurement error & plusmn; 1%, system (point) error & plusmn; 0.2m. In short, after accurately determining the fault point, dig a pit to find the fault point. 5. The principle of cable fault detector for finding cable path is to add electromagnetic wave signal to the tested cable and receive the signal of finding cable path through the pointing instrument. The minimum characteristic of receiving electromagnetic signal on the ground directly above the cable is used to determine the buried position of the cable.
How to Quickly Locate Cable Faults
How to Quickly Locate Cable Faults
With the different cable laying methods, the difficulty of cable fault location is gradually increasing. Among them, the positioning and search of bridge, tunnel and open laying in ditch is relatively simple, and the positioning and search of direct burial is the most difficult. When the fault nature is simple, the special cable fault location equipment can be used to locate the fault within dozens of minutes. When the fault is special, it often takes 4-5 days or even longer to locate the fault. How to quickly locate cable faults? When using echo method for cable fault location, sometimes by transferring the fault phase and wiring mode, complex faults are often transformed into simple faults, and the fault location is quickly determined to win time for the emergency repair of on-site lines, which is of great significance to the power supply user department. Low voltage power cables are generally multi-core cables. After laying and continuous use, they generally show two core and multi-core phase to phase or phase to ground short circuit faults. Sometimes, when it is detected that the fault waveform collected by a core is not ideal, it can be considered to convert the wiring to other fault cores for fault waveform detection, which often has unexpected effects. The collected and detected waveforms will become more typical and regular, so the specific location of cable fault point can be determined quickly. During the long-term on-site measurement of cable customers, it is found that the fault of small cross-section copper core directly buried power cable (35mm2 and below) and aluminum core cable may be accompanied by short-circuit and wire breaking fault at the same time. During on-site detection, changing the short-circuit fault to wire breaking fault measurement according to the different fault nature of each fault core will often double everything with half the effort. For the medium voltage direct buried power cable with extruded armor as the inner lining, the fault is mostly caused by external mechanical damage. When the insulating core fails, the inner lining may have been damaged. In case of special cable insulation fault, it is difficult to collect waveform with professional cable fault instrument. It can be considered to use the acoustic method to apply the high-voltage pulse directly between the steel strip and copper shielding layer of the cable, which will often be fixed quickly. In the field measurement process, we also found that when using the acoustic measurement method to locate the fault point of low-voltage cable, when the high-voltage line and ground wire are connected between the bad phase and the metal shield or armor, the sound is very small, so the probe can not be used to listen to the fixed point, and the effect is not ideal. Through the actual listening side on site for many times, it is found that if the distance between the discharge ball gap is appropriately increased, and the high voltage and grounding wire are connected between the two phases of the fault, the discharge sound will become larger and the fault point will be determined quickly.
Detection Method of Power Cable Fault
Detection Method of Power Cable Fault
1. Rough measurement of power cable fault (1) bridge method bridge method is a classical method of power cable fault location, which has a long history. Including DC resistance bridge method, DC high voltage resistance bridge method and capacitance bridge method. The resistance bridge method can only test some cable faults with low insulation resistance between single phase and ground or between two phases; High voltage bridge method is mainly used to test single-phase grounding fault or phase to phase and ground fault of main insulation with resistance greater than 10k Ω but less than megohm; The capacitance bridge method is mainly used to test the open circuit and broken wire fault of cables. The bridge method is relatively simple and convenient to operate, but it needs to know the original data such as the accurate length of the cable in advance. At the same time, it is not suitable for detecting high resistance faults. Most of the actual power cable faults are high resistance faults. Because the bridge current is very small when the fault resistance is very high, it is difficult for general sensitive instruments to detect. (2) Traveling wave method 1) low voltage pulse method low voltage pulse method is mainly used to measure the fault distance of open circuit, short circuit and low resistance faults of cables; At the same time, it can also be used to measure the cable length, wave velocity and identify and locate the middle head, T-joint and terminal head of the cable. Test principle: input a low-voltage pulse signal from the test end to the cable, and the pulse signal propagates along the cable. When encountering the impedance mismatch point in the cable, such as open circuit point, short circuit point, low resistance fault point, etc., a reflected pulse will be generated. The position of the fault point is calculated according to the round-trip time difference DT between the reflected pulse and the transmitted pulse and the pulse propagation speed v. 2) High voltage pulse method high voltage pulse method uses high voltage signal to turn cable fault into short circuit or low resistance fault instantly, so that the reflection coefficient of fault point is close to - 1, and the fault point almost produces total reflection. There are usually two basic flashover methods, namely direct flashover method and impulse flashover method. When testing cable fault by flashover method, the reflected wave formed at the cable fault point is high-voltage pulse wave, which cannot be displayed directly through the instrument. Generally, a sampler is needed to convert the high-voltage pulse formed at the fault point under the action of high voltage into the low-voltage pulse signal required by the instrument. According to different sampling methods, it is divided into voltage method, current method and voltage induction method. Wherein, R1 is the voltage dividing resistance, R2 is the sampling resistance, LP is the current sampler, C is the energy storage capacitor and B is the transformer. DC high voltage flashover method (direct flashover method): apply DC voltage to the fault cable to make the fault click through the room for discharge and flashover. Then, the fault distance can be calculated according to the transmission speed V of the traveling wave in the cable. The direct flash method is mainly used to test the flashover high resistance fault of power cable, and can also be used to test the leakage high resistance fault with particularly high resistance but lower resistance compared with the intact phase. Figure 6 shows the principle circuit of direct flash test. Impulse high voltage flashover method (impulse flashover method): due to the large equivalent internal resistance of DC high voltage power supply used in direct flashover method, the power output power is limited to a certain extent. For most leakage high resistance faults, direct flashover method cannot be tested. The impulse flashover method uses the high-capacity charging capacitor as the DC high-voltage power supply, which is connected to the fault cable to cause the flashover and discharge at the fault point to form an instantaneous short circuit. It is mainly used to test the leakage high resistance fault of power cable, and can also be used to test the low resistance, open circuit and flashover high resistance fault of power cable. The test principle circuit is basically the same as that of the direct flash method, except that a spherical gap is inserted between the energy storage capacitor and the cable, as shown in Figure 7. 2. Precise measurement of power cable fault point (1) acoustic measurement method uses the sound wave generated when the fault point is discharged for fixed point. The sound sensor detects the sound signal above the power cable. The place with loud sound is the location of the fault point. The farther away from the fault point, the smaller the vibration sound. (2) When the fault point flashover discharges under the action of impulse voltage, the acoustic magnetic synchronization method receives the electromagnetic wave and vibration sound wave generated by the discharge of the fault point at the same time, and judges whether the measured signal is generated by the discharge of the fault point to accurately judge the location of the fault point. (3) The audio induction method adds a certain power low-voltage audio signal to the fault of the cable at one end of the tested circuit. When the tested signal is transmitted to the short-circuit or disconnection point, it cannot continue to transmit along the cable, so there will be obvious signal size changes on both sides of the cable fault point. If the signal changes are detected through the receiver above the cable path, The location of the fault point can be determined. At the same time, the accuracy and integrity of various basic data of cables are also very important to improve the efficiency of fault point finding, such as cable laying direction, total cable length, distribution of cable intermediate joints, etc.
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