Kingtronics Blog

Surge arresters are designed to protect electrical equipment from damaging effects of spikes and transients caused by lightning, utility switching, isolation arcing, electrical motor cycling, or any other sudden change in electrical power flow on incoming AC power lines. 

And these devices also provide ideal protection for outdoor lighting and pole lamps, panel boards, workshops, refrigeration systems, electric motors and controls, heat pumps and air conditioning equipment, and many other electrical devices. 
More information about our products: http://www.kingtronics.com/surge-arresters/

The Ceramic gas discharge tube can be used in all places that have over-voltages.We should decide the parameter of the GDTs base on the need of the actual circuit and then select the suitable GDTs,
otherwise,we may get the reverse result.The following is the notice when using  the Ceramic gas discharge tubes:

1)Must avoid affecting the normal operation of circuit when using the Ceramic gas discharge tube.
2)Confirm the maximum peak voltage that the circuit can bear,make sure that the GDT's impulse spark-over voltage must be lower than it
3)Based on the possible impulse current energy to select the necessary impulse discharge current volume of  the Ceramic gas discharge tube
4)When the over-voltage disappears, the GDTs must extinguish rapidly to avoid affecting the normal operation of the circuit.
5)If over-voltage lasts significantly longer, GDT's discharge may continue for an extended period and generate significant thermal energy
6)Select suitable volume of  the Ceramic gas discharge tube according to the applied space.

 Over-voltage transients often occur in electric circuit. Such abnormal voltages are often caused by lightning strikes,atmospheric lightning discharges,accidental contact between power and communications lines,unexpected rise in the supply voltages of the installation as a result of misoperation,and appearance of voltage higher than normal during switching operations.The over-voltage transients,if not properly taken care of, not only cause damage to delicate components such as semiconductors,ICs and others in the equipment,but also are highly dangerous to personnel.Thus,protection against over voltages is necessary for high reliability and long life of general electronic equipment.The better protection selection for the over-voltage transients is ceramic gas discharge tubes.

The Ceramic gas discharge tube is a switching component which is controlled by voltage.It is used to be parallel connected between the line and line of equipment,or between the line and the ground(show as the bottom figures).If the over-voltage doesn't reach GDT's action voltage,the ceramic gas discharge tube will be in high resistance status.If the over-voltage is higher than GDT's action voltage,the GDT's internal gap will then break down.The Ceramic gas discharge tube is almost short-circuit at this time and limits the over-voltage to almost 0 volt within 50ns,so the surge current can be led to ground rapidly and then the equipment can be protected safely.When the over-voltage disappears, the Ceramic gas discharge tube will extinguish and return to high insulation status,preparing for the next action.  

DC spark-over voltage：The voltage at which the ceramic gas discharge tube sparks over with gradully increasing DC voltage.

Impulse spark-over voltage: The highest voltage at which the ceramic gas discharge tube sparks over with given ware-shape at a rise speed 1000V/μs, and it is also called as “pulse voltage".

Holdover voltages : The maximum DC voltage across the terminals of a ceramic gas discharge tube under which it may be expected to clear and to return to the high impedance state after the passage of a surge, under specified circuit conditions.

Alternating discharge current : The r.m.s. value of an approximately sinusoidal alternating current passing through the ceramic gas discharge tube.

Impulse discharge current: The peak value of the impulse current passing through the ceramic gas discharge tube, and it is also called as pulse discharge current or surge discharge current, including 10/1000μs long-wave discharge current and 8/20μs short-wave discharge current.

Insulation resistance：DC resistance of the gas discharge tube under specified conditions. Test voltage must be lower than DC spark-over voltage.

Inter-electrode capacitance : The capacitance between any two electrodes in the gas discharge tube. Its value is mainly determined by the size of electrode and distance between electrodes. In addition, the capacitance is also related to the lead wire length, spacing and dielectric in the ceramic gas discharge tube.

Gas discharge tube generally uses ceramic as its packing housing. The discharge tube is filled with inert gases with stable electrical characteristics and provided with structure of two or three electrodes .When certain voltage is applied to inter-electrode of discharge tube, nonuniform electric field will be produced. Gases begin to ionize under the effect of electric field. When applied voltage reaches inter-electrode field intensity and exceeds the insulation strength of inert gas, the electric arc will be produced between the electrodes to ionize gas, and the negative resistance characteristic will be produced. 

Thus, the insulation state will be turned into conductive state immediately. i.e. when electric field strength exceeds the puncture strength of gas, the gap discharge will be caused, and inter-electrode voltage will be limited. That is to say, when there is no surge, it will be in the state of open circuit. When surge occurs, the electrode plates in the discharge tube close and connect，allowing harmful current to be discharged via ground wire or circuit loop. 

When surge disappears, the discharge tube restores to the state of high impedance rapidly, and the circuit continues to work properly.

Surge arresters are used to protect electronic appliances and machineries from damages caused due to sudden voltage surges. 

Because of the changing lifestyle of the working population and the increasing disposable income, automated electronic products are used more and more widely. For protecting these devices from voltage fluctuations, the demand of surge arresters becomes large. Furthermore, the growing awareness for need of renewable energy sources is also acting as a driver for the market. Using renewable sources of energy such as sun, water and wind, this factor is creating the need for surge arresters in order to protect the heavy machineries from damages caused due to voltage overflow and fluctuations. 

Kingtronics sell 2-Electrode arresters and 3-Electrode arresters. Surge arresters operate on the gas-physical principle of the highly effective arc discharge. Electrically, surge arresters act as voltage-dependent switches.
More details about Kt Kingtronics Surge Arresters, please see:
http://www.kingtronics.com/surge-arresters

Surge arresters are classical components for protecting the installations of the telecommunications. It is essential that IT and telecommunications systems -with their high-grade but sensitive electronic circuits – be protected by arresters. They are thus fitted at the input of the power supply system together with varistors and at the connection points to telecommunication lines. They have become equally indispensable for protecting base stations in mobile telephone systems as well as extensive cable television (CATV) networks with their repeaters and distribution systems.

These protective components are also indispensable in other sectors:
● In AC power transmission systems, they are often used with current-limiting varistors
● In customer premises equipment such as DSL modems,WLAN routers, TV sets and cable modems
● In air-conditioning equipment
The integral black-box concept offers graduated protection by combining arresters with varistors, PTC thermistors, diodes and inductors to create an ideal solution for many applications.

Surge Arresters Key characteristics:
● DC spark-over voltage : 70 to 6000 V
● Impulse discharge current (8/20 μs) : max. 100 kA
● Impulse discharge current (10/350 μs) : max. 100 kA
● Alternating discharge current (1 s) : max. 20 A
● Alternating discharge current (0.2 s) : max. 300 A
● Arc voltage: 10 to 35 V
● Insulation resistance: min. 1 GΩ
● Capacitance: min. 0.2 pF

Kingtronics sell 2-Electrode arresters and 3-Electrode arresters. Surge arresters are designed to protect electrical equipment from damaging effects of spikes and transients caused by lightning, utility switching, isolation arcing, electrical motor cycling, or any other sudden change in electrical power flow on incoming AC power lines.

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 independent 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.

Kingtronics sell 2-Electrode arresters and 3-Electrode arresters, as well as SMD Surge Arresters.
Gas Discharge Tubes for Overvoltage Protection

Surge Arresters Applications
*  Automotive
– On-board chargers in electric and hybrid vehicles
– EV charging stations
*  Consumer
– Air-conditioning
– Power supplies
– Printers and telefax
*  Industrial
– LED street lighting
– Photovoltaics
– RF antenna circuits
– UPS

Click here to know more about our Surge Arresters: www.kingtronics.com/surge-arresters/