Gas Discharge Tube (GDT)2020-09-04
What is Ceramic Gas Discharge tube ?
The ceramic discharge tube is hermetically encapsulated with ceramics. The inside is composed of two or several gaps metal electrodes , pumping into an noble gas, argon and neon . When the two electrode voltage reach to voltage spike making the noble gas broken down , gas discharge tube start discharge . from high impedance to low impedance, so that the surge voltage rapidly become short circuit to near zero voltage, and releasing the overcurrent into the ground, thereby protecting the subsequent circuit.
GDT is one of the most widely used lightning protection device at present , It can play a very good protective role in both the lightning protection of AC and DC power supply and the lightning protection of various signals.
A small reactance is added to the neutral point of the parallel high voltage reactor, which can block the power frequency voltage transfer and series resonance in non full phase operation.
Gas discharge tube classification :
Socay offers surface mounted device (SMD) ,diode and triode GDT , The range of voltage is from 75V - 6KV , over one hundred specification . Production, monitoring and management are strictly carried out according to CITEL standard.
What is the function of the Gas Discharge Tube ?
GDT often use into the ? grade or the ∥ grade in multilevel protection circuit , It plays the role of discharging lightning transient overcurrent and limiting overvoltage. The discharge tube plays a protective role by restricting the voltage to a lower level.
All electrical products have a certain?affordability for?current and voltage. Once exceeded?this affordability , electrical appliances will suffer different degrees of damage. The ceramic gas discharge tube is a very good protection device.
When it Parallel in the circuit, the device does not working, the resistance is high, and it can be regarded as open circuit, almost no effect on the circuit. When there is an abnormal pulse, it reach into the working voltage value then the resistance drops instantly, and releasing the current suddenly . After the abnormal high voltage disappears, it returns to a high impedance statement, the circuit is working as usual .
The application of GDT
Industrial power supply; Tel-communication power supply ; inverter power supply ; UPS uninterruptible power supply ; steady voltage power supply ; drive power supply ; switch power supply ; power module; isolator; inverter; medical equipment; 485 converter; communication product ; stabilizer; security product; lightning arrester.
The characteristics of gas discharge tube .
①?the DC breakdown voltage Vsdc: When apply breakdown voltage value 100V/s DC voltage?into the GDT, It is the normal voltage . Frequently-used type 90V , 150V , 230V , 350V , 470V , 600V , 800V ect . Socay have Max voltage 3000V 、Minimum voltage 70V . Tolerance range , usually ±20% or ±15%?.
②?Impulse Spark-over voltage Vsi :When Apply breakdown voltage value 1KV/μs impulse voltage , due to the reflect speed is slower , the impulse sprark-over voltage will be higher than the DC spark-over voltage .
③Impulse discharge current Idi :There are have two kinds wave : short-wave 8/20μs impulse discharge current and long-wave 10/1000μs impulse discharge current .The impulse discharge current is divided into single impulse discharge current (8/20μs?wave impulse 1 time) and standard?impulse discharge current (8/20μs?wave impulse 10 times).In general ,the latter impulse discharge current is about the half of the former ,have 2.5KA 、5KA 、10KA 、20KA and the so on .