Kingtronics Blog

Kingtronics surge arrester divides into two kinds: 2-Electrode arresters and 3-Electrode arresters.

What is surge arrester? It is a product installed near the end of any conductor which is long enough before the conductor lands on its intended electrical component. The purpose is to divert damaging lightning-induced transients safely to ground through property changes to its varistor in parallel arrangement to the conductor inside the unit.

Surge arrester is also called a surge protection device (SPD) or transient voltage surge suppressor (TVSS). They are only designed to protect against electrical transients resulting from the lightning flash, not a direct lightning termination to the conductors.

SKT--Surge Arrester:
SKT-2R-230A6L Bulk RoHS
SKT-3R-230AL Bulk RoHS

Application: distribution system, protector, power station equipment, satellite receiver, server, communication system...

Gas-filled surge arresters operate on the gas-physical principle of the highly effective arc discharge. Electrically, surge arresters act as voltage-dependent switches. As soon as the voltage applied to the arrester exceeds the spark-over voltage, an arc is formed in the hermetically sealed discharge region within nanoseconds. The high surge current handling capability and the arc voltage, which is almost independend of the current, short-circuit the overvoltage. When the discharge has died down, the arrester extinguishes and the internal resistance immediately returns to values of several 100 MΩ.

The surge arrester thus meets almost perfectly all requirements made on a protective element. It reliably limits the overvoltage to permissible values, and – under normal operating conditions – the high insulation resistance and the low capacitance contribute to the fact that an arrester has virtually no impact on the system to be protected.

Telephone / fax / modem protection

Telephones, faxes and modems are equipped with sophisticated but sensitive electronics. Typical circuits used to protect them with surge arresters are shown in following Fig.

These arresters protect against common-mode interference voltages, i.e. surge voltages that appear in both lines to ground. In the event of an over voltage, the arrester protects both exchange lines by conducting the surge current away to ground.

The principal "active" element of the Surge Arrester is a metal oxide varistor characterized by high non-linearity. At a working voltage mainly a capacity current flows smaller than 1 mA. Any voltage increase causes a large increase of current flowing through the varistor, leading in turn to immediate limitation of further voltage increase on arrester terminals. When the over voltage disappears, the arrester immediately returns to its basic state.

Surge Arresters are equipped with a disconnecting device that disconnects the arrester from the network if it becomes damaged as the result of over voltage of too high energy or inadmissible voltage increase in the system. If such a situation occurs then the bottom terminal of the disconnecting device is "rejected" by the spring inside. This terminal remains suspended on an insulation "leash".

Kingtronics sell 2-Electrode arresters and 3-Electrode arresters. Following are 2-Electrode arresters and 3-Electrode arresters’s pictures.