Lightning 420V Metal Oxide Varistor Surge Protection High Energy MOV 20D681K

Lightning Protection Metal Oxide Varistor 20D681K 20mm 420VAC For Charging Pile

Function Of The Lightning Protection Metal Oxide Varistor 20D681K

Varistors are used as control or compensation elements in circuits either to provide optimal operating conditions or to protect against excessive transient voltages. When used as protection devices, they shunt the current created by the excessive voltage away from sensitive components when triggered.

Specifications Of 20D Series Metal Oxide Varistor

Put “J” in free Code Stands For High Surge Series

Dimension Of The Lightning Protection Metal Oxide Varistor 20D681K(Unit:mm)

Max Thickness Of The Lightning Protection Metal Oxide Varistor 20D681K

Application Example Of The Lightning Protection Metal Oxide Varistor 20D681K

Package Of The Lightning Protection Metal Oxide Varistor 20D681K

Selections of Varistors

When selecting a varistor, the specific conditions of the circuit must be considered. Generally, the following principles should be followed.

1 Selection of Varistor Voltage V1mA

According to the power supply voltage, the power supply voltage continuously applied across the varistor cannot exceed the “maximum continuous operating voltage” value listed in the specification. That is, the maximum DC working voltage of the varistor must be greater than the DC working voltage VIN of the power line (signal line) which is VDC ≥ VIN; for the varistor selection of the 220V AC power supply, it is necessary to give full consideration to the fluctuation range of the working voltage of the power grid, and to select the varistor voltage value of the varistor, there should be enough allowance for the selection of the varistor. The general fluctuation of the domestic power grid is 25%. A varistor with the voltage of 470V to 620V should be selected. Selecting a varistor with a higher voltage can reduce the failure rate and prolong the service life, but the residual voltage is slightly increased.

2 Selection of Flow Rate

The nominal discharge current of the varistor should be greater than the surge current required to withstand or the maximum surge current that may occur during operation of the equipment. The nominal discharge current should be calculated according to the value of more than 10 shocks in the surge life curve of varistor, which is about 30% (0.3IP) of the maximum impulse flow rate.

3 Selection of Clamping Voltage

The clamp voltage of the varistor must be smaller than the maximum voltage (safe voltage) that the protected component or device can withstand.

4 Selection of CP

For high frequency transmission signals, the Cp should be smaller, and vice versa.

5 Resistance Match

The relationship between the internal resistance R(R≥2Ω) of the protected component (circuit) and the transient internal resistance Rv of varistor: R≥5R. For protected components with small internal resistance, use large-capacitance varistor as much as possible without affecting the signal transmission rate.