Surge Protector Circuit Using Mov

About the mov metal oxide varistors.

Surge protector circuit using mov.

Metal oxide varistor basics. Question regarding surge prevention in electronic ballast. Attached is the surge protection circuit we have decided for our group research thesis. When exposed to high transient voltage the mov clamps voltage to a safe level.

A metal oxide varistor or mov is an electronic component that protects equipment from voltage surges in a power line such as from lightning strikes. Transient protector using inductors and mov. This is a surge protector. 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.

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. In general mov selection for the electrical protection of circuits from power supply transients and spikes is often little more than an educated guess. Home home electrical circuits ac 220v 120v mains surge protector circuits the values of the components i intend to use is. Varistors can absorb part of a surge.

The rationale is that if the likelihood of surge damage to the mov is low the risk of fire is adequately addressed. Traditional radial through hole mov metal oxide varistor devices are available in diameters of 5mm 7mm 10mm 14mm 20mm and 25mm. Mov is the most commonly used type of varistor. Thermistor sck201romsby size 20mm termination radial.

A word of caution. A metal oxide varistor absorbs potentially destructive energy and dissipates it as heat thus protecting vulnerable circuit components and preventing system damage. 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. Excessive voltage triggers the mov into action.

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