Figure 4 shows the simplified equivalent circuit of a metal oxide varistor. How to choose the right metal oxide varistor mov ask question asked 2 years, 1 month ago. Make us your source for harris metal oxide varistors and other products. A surge in excess of the specified withstanding surge current may cause short circuits or package rupture with expulsion of material. Reliability evaluation of metal oxide varistors for maintenance scheduling. Nvd metal oxide varistor disc type koa speer electronics, inc. Metal oxide varistors, more commonly known as movs are devices that provide excellent transient voltage suppression. Metal oxide varistors movs radial lead varistors ciii varistor series should transients occur in rapid succession, the average power dissipation is the energy wattseconds per pulse times the number of pulses per second. The varistor is bidirectional and is based around a.
Mov metal oxide varistors testing all about circuits. Mark, conform to ul 1414, ul1449 edition 3, as listed on dti ul file number e319342. Stability of zinc oxide varistors a thesis submitted to the university of manchester for the degree of doctor of philosophy in the faculty of engineering and physical. Penlington university of northumbria, newcastle upon tyne, uk metal oxide varistors are znobased. Jun 08, 2015 the burning issue of metal oxide varistors and how to stop thermal runaway. Metal oxide varistor mov market size, share, growth, trends.
Bourns mov product portfolio offers 7, 10, 14, and 20 mm radial leaded varistor devices which protect against overvoltage transients such as lightning, power contact and power induction. To assure our customers quality harris metal oxide varistors and other products and services at international standards, galco maintains iso90012000 certification. If lightning strikes a nearby power line, the high voltage causes the mov to become a shunt, preventing the. The metal oxide varistor or mov for short, is a voltage dependant resistor in which the resistance material is a metallic oxide, primarily zinc oxide zno pressed into a ceramic like material. Low inductance construction with excellent response 6. Tvrd series disc type varistor for surge protection high surge series thinking electronic industrial co. Metal oxide varistor mov technology is the most prevalent technology utilized in electrical transient protection products today. It is a mixture of zinc oxide grains and other metal oxides like cobalt, manganese etc.
General electric metal oxide varistors now in stock galco stocks an extensive and comprehensive line of general electric metal oxide varistors for most industrial applications one of hundreds of categories of industrial and electronic products in stock. Measuring the energy handling capability of the metal oxide varistors m. They are primarily protective devices to dump the current in excessive over voltage events and so save the circuit board or end equipment. A varistorvoltage dependent resistor vdr is a component which has a voltage current characteristics that is very much similar to that of a diode.
Metal oxide varistors movs selection guide engineering360. Varistor symbol and applications metal oxide varistor. Large capability to withstand high surge current 5. Help identifying a varistor electrical engineering stack. The paper confirmed that the critical voltage of the. The varistors are available in a number of packaging. High energy metal oxide varistors hvp high voltage. Pdf comparative study of metal oxide varistors movs for. Nippon chemicon corporation metal oxide varistorstnr manufacturing and selling capacitors and electronics components. Metal oxide varistor electronics repair and technology news. These clamping devices contain a matrix of zinc oxide grains sandwiched between two metal plates which serve as electrodes. Directwrite fabrication of zinc oxide varistors valeria tohver, sherry l. Varistors vary quite heavily between different models.
A metal oxide varistor mov is an electronic device that protects an appliances power supply from voltage spikes and surges in the ac power line. Within the useful varistor voltage range, the voltagecurrent relationship is approximated by the expression. This is useful for controlling how much electric current travels to certain parts of electronic devices. Modeling metal oxide varistors mov in short circuit calculations krishnat patil staff software engineer krishnat.
Varistormetal oxide varistor is the purpose of a promise of overvoltage protection elements, either ac or dc circuits, simply varistor and the protected electrical equipment or components in parallel to. It is called so as the component is made from a mixture of zinc oxide and other metal oxides like cobalt, manganese and. New product information aluminum electrolytic capacitors multilayer ceramic capacitors film capacitors metal oxide varistorstnr. They are voltage dependent, nonlinear devices that provide transient suppression. Metal oxide varistormov power supplies home electrical appliances industrial devices surge protectors telecommunication system sfv 10 d 471 k a set fuse varistor d round s square. Features zinc oxide varistor are nonlinear resistors utilize a semiconductor electronic ceramic element mainly composed of zinc oxide and its resistors change as a function of the applied voltage. Metal oxide varistors mov data sheet features wide operating voltage v 1ma range from 18v to 1100v fast responding to transient overvoltage large absorbing transient energy capability low. A new method for synthesizing zinc oxide nanoparticles used zndehss diethylhexyl sulfosuccinate as a surfactant with an ethanolinoil microemulsion. Metal oxide varistors definition of varistor terms rated rms voltage, rated dc voltage the maximum designated values of power system voltage that may be applied continuously between the terminals of a device varistor voltage test characteristic that is used to classify varistors by type. Comparative study of metal oxide varistors movs for failure mode identification thesis pdf available december 2004 with 2,376 reads how we measure reads.
Ultramov varistors are primarily intended for use in ac line voltage applications. In this region, the ohmic resistance of the zinc oxide causes a higher voltage drop. Littelfuse metal oxide varistors mouser electronics. Simple and inexpensive, the mov absorbs the energy in a surge, preventing it from damaging other devices in a circuit. A metal oxide varistor, or mov, protects sensitive electronic equipment from voltage spikes in the power line.
Pdf reliability evaluation of metal oxide varistors for. Pdf metal oxide varistors movs are the essence of surge protection devices and have dominated the market with their highly nonlinear. Jameco sells metal oxide varistor and more with a lifetime guarantee and same day shipping. This component is used to protect electrical devices from high transient voltages. The metal oxide varistors offer a choice of varistor voltages from 18 v to 820 v and v rms voltages from 11 v to 510 v. What is a metaloxide varistor and how it protects a drive. Aug 28, 2007 metal oxide varistor mov are voltage dependent symmetrical resistors intended to protect equipment from transient voltages resulting from lightning strikes. The basic operation, electrical characteristics, and applications of littelfuses metal oxide varistors. The za series of transient voltage surge suppressors are radiallead varistors movs designed for use in the protection of low and medium voltage circuits and systems. The boundaries between grains form diode junctions which allow current to. Users should verify actual device performance in their specific applications. Pdf ul1449 e95427 ul1414 e65426 lr97864 9000kcal e1006q tnd14 tnd10sv271ktlbpaa0 tnd10v271k. While it may look similar to a capacitor, you can identify the device by its color, markings and location.
It is generally manufactured from a material such as zinc oxide, zno, although another material that is used is silicon carbide, sic and this provides similar properties. Thus, mov manufacturers are unable to tap the market for low voltages. Schematic depiction of micr ostructure of a metal oxide varistor. Global metal oxide varistor market is segmented by application into electronic discharge esd and overvoltage protection. The za series of transient voltage surge suppressors are radiallead varistors movs. The mov07dxxxk series of 7 mm radial leaded varistor devices protects against overvoltage transients such as lightning, power contact and power induction. Metal oxide varistors when to use varistor vs tvs diode. Metal oxide varistormov failure all about circuits. Metal oxide varistor mov are voltage dependent symmetrical resistors intended to protect equipment from transient voltages resulting from lightning strikes. Siov siov metal oxide varistors metal oxide va ristors 2008 published by epcos ag corporate center edition 112007 ordering no. Metal oxide varistors movs radial leaded varistors aumov varistor series description features agency approvals absolute maximum ratings for ratings of individual members of a series, see device ratings and specifications chart agency agency file number e320116 only 14vac to 42vac for epoxy coated. The operation of metal oxide varistor and silicon carbide varistor are very similar.
For example, a metal oxide varistor has a different build than a series built out of crystals. Metal oxide varistors consist of approximately 90% zinc oxide as a ceramic base material plus other filler materials for the. Because of the metal oxide, the device has been named a metal oxide varistor and has been trademarked mov. Sep 22, 2015 the operation of metal oxide varistor and silicon carbide varistor are very similar.
Nippon chemicon corporation metal oxide varistorstnr. Global metal oxide varistors market is segmented by type into surface mount and disc. View detailed import data, price, monthly trends, major importing countries, major ports of varistor metal oxide under hs code 8533. One of the movs connected between earthgnd and line fails frequently. Movs or metal oxide varistors are a very popular product and widely used. The devices have a high current handling, high energy absorption. A gadget may have thousands of transistors, resistors and other components, but only one or two varistors.
Application note thinking electronic industrial co. A resistor is a circuit that does not conduct electricity well. The surfaces of the intercrystalline fracture follow the znograin boundaries. Typical applications include motor control, telecom, automotive. Metal oxide varistor mov industry 2018 market research. They use these mov metal oxide varistors for light ballast circuits they are these very small and the color is blue with the circuit turned off, how do you test and check mov varistor. Apr 18, 2020 a metal oxide varistor is a device used as a component in electrical equipment. Pdf comparative study of metal oxide varistors movs. Completely uptodate, this is the first comprehensive monograph on metal oxide varistors with a focus on microstructure, conduction mechanisms, device failures, ageing, additive impacts and future. The burning issue of metal oxide varistors and how to stop. To search our extensive online database, simply enter the part number. Metal oxide varistors definition of varistor terms rated rms voltage, rated dc voltage the maximum designated values of power system voltage that may be applied continuously between the terminals of. We also have an extensive resource database for sourcing and crossreferencing parts.
Nippon chemicon offers varistors, which are also suitable for automotive compliance according to aecq200. Feb 15, 2011 varistor degradation is defined by manufacturers life expectancy charts using curves that relate current, time, and number of transient pulses. The power so developed must be within the specifications shown on the. They are used to protect vulnerable electronic circuits and components from overvoltage conditions that can cause damage. Ratings and characteristics maximum ratings part number previous part number just for your reference, p1 h0 f w2 1. The main difference between a silicon carbide varistor and a metal oxide varistor is the amount of leakage current. A surge in excess of the specified withstanding surge current may cause short circuits or package rupture with expulsion.
Bulk on tape and reel on tape in ammopack fanfold the basic ordering code for each option is given in tables titled varistors on tape on reel, varistors on tape in ammopack and varistors in bulk. Metal oxide varistor mov market is likely to witness substantial growth at a healthy cagr of 11. The series of a varistor varies depending on the voltage it can hold, the devices it is used to control, and the type of power used in its build. Vb type t plastic encapsulated type varistor for surge protection features 1. Siov metal oxide varistors selection procedure date. This type contains a ceramic mass of zinc oxide grains, in a matrix of other metal oxides, such as small amounts of bismuth, cobalt, manganese oxides, sandwiched between two metal plates, which constitute the electrodes of the device. Vdrh series vdr metal oxide varistors high surge vishay. Dear all, i am using an mov for surge protection in one of our application. The name is a portmanteau of variable resistor, which is misleading since it is not continuously uservariable like a potentiometer or rheostat and is capacitor rather than resistor at low field. Normally, the mov has very high electrical resistance.
Metal oxide varistors, also known as movs are one of the most common types of varistors. The most common modern type of varistor is the metaloxide varistor mov. It is used to protect the circuit from high voltage spikes by varying. A fully degraded varistor remains functional no catastrophic failure and is not visibly damaged. A varistor fully degrades typically when its clamping voltage has changed by 10%. Please confirm technical specifications before you order andor use. Siov metal oxide varistors data book 2008 schmidmultitech sro. The metal oxide varistor, mov, is the most widely used form of varistor. General electric metal oxide varistors now in stock. A metal oxide varistor mov is a protection component used in power supply circuits that is powered directly from ac mains.
Varistor voltage voltage across the varistor measured at 1madc see. This component is located near the ac supply input and before the bridge rectifier. Lewis department of materials science and engineering, university of illinois, urbana, illinois 61801. Tvmb series smd type surge suppressor thinking electronic industrial co.
This form of varistor is the most widely used and it is the form that is often referred to when the term varistor is stated. Comparative study of metal oxide varistors movs for failure mode identification. April 2004 iaei news 5 photo 1 is a 40 mm mov with an mcov rating of volts ac. They are a type of nonlinear device that feature similar characteristics to zener diodes. Specifications are subject to change without notice. Measuring the energy handling capability of metal oxide. We make it easy to find the exact general electric metal oxide varistor you need. Sm20 series 20 mm smd varistors the littelfuse sm20 series is a surfacemount metal oxide varistor. A metal oxide varistor starts conducting current at rated voltage and it stops the conduction if the applied. The most common modern type of varistor is the metal oxide varistor mov. A metal oxide varistor starts conducting current at rated voltage and it stops the conduction if the applied voltage is below the threshold value. The most famous type of varistor is metal oxide varistor mov, which is also called as zno varistor. Metal oxide varistors movs radial lead varistors ultramov varistor series description the ultramov metal oxide varistor series is designed for applications requiring high peak surge current ratings and high energy absorption capability. Dec 24, 2012 mov metal oxide varistor from the name we get to know that it is associated with oxides of metals.
Varistors are in stock and ship sameday at mouser electronics from industry leading manufacturers. The use of mov not only reduces the chance of electrical damage buut also improves equipment reliability. Metal oxide varistors high energy disc varistor series metal oxide disc varistors features the disc varistor series of transient surge suppressors are industrial provided in disc form for unique packing by highenergy disc varistors movs intended for special applications customer requiring unique electrical contact or packaging methods. Metal oxide varistor mov data sheet features wide operating voltage v 1ma range from 18v to 1800v fast responding to transient overvoltage large absorbing transient energy capability low. Mov14dxxxk series metal oxide varistor rohs directive 200295ec jan. A test current of 1 ma dc is typically used to determine. This type contains a ceramic mass of zinc oxide grains, in a matrix of other metal oxides, such as small amounts of. Import data and price of varistor metal oxide under hs code. Vdr metal oxide varistors standard additional resources ordering information the varistors are available in a number of packaging options. The metal oxide varistor, with its extremely attractive price performance ratio, is an ideal component for limiting surge voltage and current as well as for absorbing energy.
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