Surge Protector Circuit Using Mov

How to test a mov metal oxide varistor surge protector device.

Surge protector circuit using mov.

They are fit for providing voltage surge protection for a wide variety of applications and include the c iii itmov la tmov ra ultramov ultramov25s and za series. Metal oxide varistor basics. However metal oxide varistors are available in a wide range of varistor voltages from about 10 volts to over 1 000 volts ac or dc so selection can be helped by knowing the supply voltage. Traditional radial through hole mov metal oxide varistor devices are available in diameters of 5mm 7mm 10mm 14mm 20mm and 25mm.

This is just one part of our project which is to have a built in sure protection for wall outlets using 2 diodes with cathodes connected to each other and movs. This design is not great it s slow to act depending on a relay it will take many ms to switch off at current max relay current and a 250v mov in 120v installation won t help much either. Simple and inexpensive the mov absorbs the energy in a surge preventing it from damaging other devices in a circuit. Mov is the most commonly used type of varistor.

The rationale is that if the likelihood of surge damage to the mov is low the risk of fire is adequately addressed. This is a surge protector. Excessive voltage triggers the mov into action. Attached is the surge protection circuit we have decided for our group research thesis.

Thermistor sck201romsby size 20mm termination radial. When exposed to high transient voltage the mov clamps voltage to a safe level. Transient protector using inductors and mov. A metal oxide varistor absorbs potentially destructive energy and dissipates it as heat thus protecting vulnerable circuit components and preventing system damage.

Varistors can absorb part of a surge. It is called so as the component is made from a mixture of zinc oxide and other metal oxides like cobalt manganese and so on and is kept intact between two electrodes which are basically metal plates. Home home electrical circuits ac 220v 120v mains surge protector circuits the values of the components i intend to use is. Using this option typically requires the mov to have a nominal turn on threshold that is above 1500 v rms which has the effect of potentially limiting the usefulness of the mov surge protection.

About the mov metal oxide varistors. In general mov selection for the electrical protection of circuits from power supply transients and spikes is often little more than an educated guess.