What happens when MOV fails?
The prominent failure mode for the MOV is sustained overvoltage. Under these conditions, the MOV begins to conduct power frequency (50 Hz to 60 Hz) current. The MOV ultimately reaches its maximum energy capacity and enters thermal runaway.
How does a voltage dependent resistor work?
A voltage dependent resistor has a nonlinear varying resistance, dependent on the voltage applied. The impedance is high under nominal load conditions, but will sharply decrease to a low value when a voltage threshold, the breakdown voltage, is exceeded.
How does varistor protection circuit?
When a voltage surge exceeding a specified voltage (varistor voltage) is applied, the varistor suppresses the voltage to protect the circuit. When the voltage surge does not exceed the varistor voltage, the varistor works as a capacitor.
What is MOV in power supply?
MOV stands for Metal Oxide Varistors, a voltage-limiting protection device with nonlinear volt-ampere characteristics. It is a matrix structure composed of zinc oxide particles. The grain boundaries between the particles have electrical characteristics similar to bidirectional PN junctions.
How is varistor made?
Varistors are formed when crystals of silicon carbide or metal oxides are pressed into a ceramic material. Then sintering of the material is done at high temperature after it gets dried. The electrical characteristics of the device are dependent on temperature provided and atmospheric conditions.
Can I replace a varistor with a capacitor?
You can replace it with a new one provided it is for the same voltage levels that it triggers. This AC and DC voltage ratings are the important parts and then the energy capacity. Energy cap. is not a major issue in Computer PSUs since the usually use a small varistor there.
What is MOV capacitor?
A Metal Oxide Varistor (MOV) is a protection component used in power supply circuits that is powered directly from AC mains. It is used to protect the circuit from high voltage spikes by varying its resistance.
How do you calculate MOV?
The current rating of the MOV could be twice that of the SMPS rating, meaning if the SMPS wattage is rated at 24 watts at the secondary, then the primary could be calculated as 24/285 = 0.084 amps, therefore the MOV current could be anywhere above 0.084 x 2 = 0.168 amps or 200mA.
How do I test a MOV with a multimeter?
Work the lead loose with a long-nose pliers. Turn the multimeter on and set its function knob to read resistance. Touch the meter probe tips to the MOV’s leads and measure its resistance. If it has a resistance much under 100 ohms, it has blown.
What is MOV component?
How do I read varistor code?
Touch one meter probe to the free varistor lead and the other probe to the connected lead. Read the resistance on the meter. If it reads nearly infinite resistance, the varistor is still good. If it reads very low resistance, the varistor is blown.
What happens when a varistor fails?
The result is that a few conducting paths with low breakdown voltages to carry most of the current and become hotter. If the temperature of these paths reaches the vicinity of 1000o C, melting occurs and the MOV is destroyed.
What is the best MOV?
Windows Movie Maker. Windows Movie Maker,now discontinued by Microsoft,is the built-in video editor on various versions of Windows.
How to open a .MOV file?
– To open mov file on Windows 10 PC is to download and install QuickTime on your computer. You can also use the Windows Media Player to play the files. – Next, install a third-party video player, which is designed to play MOV files. – Secondly, install a media player.
How to convert VOB to mov easily?
Open the Wondershare Free VOB to MOV converter and import MOV files.
What does MOV mean in electrical terms?
Rated Capacity (Battery)