How to choose a surge protector? 1, according to the protected line formats, such as: single-phase 220V, three-phase 220 / 380V TNC / TNS / TT, etc., to select the appropriate standard SPD 2, according to the protected device withstand voltage level, the SPD selection voltage protection level Up. General resistance to impulse voltage terminal equipment 1.5kV, specific reference GB 50343-5.4. Up value is less than its withstand voltage can be. 3, according to the way the line is introduced, whether the result of direct lightning strikes hit by lightning current spread of risk, select primary or secondary SPD. SPD is a lightning current discharge waveform parameters of 10/350. 4, GB 50057-6.3.4 in shunt calculations, calculate the required line discharge current strength, select appropriate discharge capacity of SPD, SPD nominal discharge current required parameter is greater than the line shunt surge currents can be. As for the models, different models from different manufacturers, no reference value. We recommended to choose well-known brand, and now mine market was mixed, not freeloaders and the use of inferior products. Surge protection design principles, characteristics, use of the category? Design principles in the most common surge protector surge protector, has called a metal oxide varistor (Metal Oxide Varistor, MOV) of the element for transfer excess voltage. Shown, MOV to FireWire and ground are connected together as shown. MOV consists of three parts: the middle is a metal oxide material, the two semiconductor connected to power supply and ground. These semiconductors have a voltage that varies with the variable resistor. When the voltage drops below a certain value, the movement of electrons in a semiconductor would produce extremely high resistance. Technical data suppression diode breakdown voltage, it is the reverse breakdown current at a specified (usually lma) breakdown voltage surge protectors at home, which is rated breakdown voltage of the zener diode is generally 2.9V ~ 4.7 V range, while the avalanche breakdown voltage rating of the diode is often in the range of 5.6V ~ 200V. ⑵ maximum clamping voltage: It refers to the highest voltage of the tube at high current waveform by a predetermined time, the emergence of its ends. ⑶ pulse power: it refers to the current waveform in a predetermined (eg 10 / 1000μs), the product pipe maximum clamping voltage across the current equivalent of the tube. ⑷ reverse displacement voltage: It refers to the maximum voltage communication surge protector tube reverse leakage area, which can be applied at both ends, the tube should not be at this voltage breakdown. This reverse displacement voltage should be significantly higher than that of the protected electronic system maximum operating voltage peak supply surge protector, that is not in a weak state in the conduction system during normal operation. ⑸ maximum leakage current: it refers to the displacement in the reverse voltage is applied, the tube maximum reverse current flowing. ⑹ response time: 10-11s Surge Protector (Surge protection Device) is a device indispensable lightning protection of electronic equipment, in the past often referred to as a surge protector operating principle "lightning" or "over-voltage protection" English abbreviation for the SPD. Role surge protector is fleeing the instantaneous power lines, the signal transmission line over-voltage limit within the device or system can withstand the voltage range, or the powerful lightning current into the ground, to protect the protected equipment or system from impact damage. Surge protectors vary according to the type and structure of different purposes, but it should contain at least one non-linear voltage limiting element. Basic components for the surge protector are: discharge gap, inflatable discharge, varistors, suppression diodes, and choke coils. Room surge protectors surge protector _ _ Panjin on the people by the Shenyang Electric people Electric Co. Shenyang Electric Co. on people (www.zsmsy.com) (www.smdqee.com) strong, credible, and other industries in other Shenyang, Liaoning province has accumulated a large number of loyal customers. The company better work attitude and constantly improve the innovative ideas will lead sink into the brilliant electric and you work for a better future!