On the selection of lightning protection tube

西里古1992

On the selection of lightning protection tube [Copy link]

 

This is the lightning protection tube at the input end of the machine. There are both X and Y ones, RV001~RV003

The Surge test item standard is CM-2kV, DM-1kV

Then I looked at the RV002 specification sheet, and its parameters are lightning current 2000A, and the start voltage 300V, impedance and so on.

I just don't know how to select lightning arresters? The voltage values given are all current values.

chunyang

The connection method of RV002 and RV003 is incorrect. Three TVSs should be used, one across the two ends of the protected circuit, and two respectively connected between the protected circuit and the protective ground. The protective ground must be separately and reliably connected to the earth. The TVS starting conduction voltage must be greater than the peak value of the input voltage and leave an appropriate margin.

maychang

RV002 and RV003 are connected to both sides of the common mode inductor. What does this mean? It is impossible to generate high voltage on the windings of the common mode inductor. This connection is useless.

Gen_X

I have an imported instrument, and its TVS always has problems. I wanted to learn how to combine it with lightning protection, but I was confused.

langtuodianzi

The gas discharge tube connected in parallel on the common-mode inductor has the same function as the ceramic discharge tube connected in series with the varistor across the L-phase and N-phase ground, both of which are used to prevent common-mode lightning strikes.

The gas discharge tube connected in parallel on one side of the common mode inductor utilizes the short-circuit characteristic of the gas discharge tube to suppress the resonance characteristic, which can effectively reduce the resonance voltage spike.

Gen_X

@langtuodianzi

This circuit is correct! Thanks!

TVS must be after these circuits, otherwise it is an unreasonable design!!!

I have modified the foreigner's circuit "design", and we think that the TVS breakdown problem we have encountered violates this principle!

This is a design quality accident caused by foreigners!

langtuodianzi

The withstand surge current of the primary protection circuit should be greater than the maximum current capacity that the circuit may withstand. The surge current capacity of the second and third level protection circuits can be reduced step by step.

Try to choose gas discharge tubes or varistor devices for the primary, and TVS diodes (TVS tubes have limited current absorption capacity) for the secondary.

西里古1992

langtuodianzi posted on 2023-2-3 09:44 The withstand surge current of the primary protection circuit should be greater than the maximum current capacity that the circuit can withstand. The surge current capacity of the second and third level protection circuits can be...

I don't quite understand the primary and secondary protection circuits mentioned here. What is the distinction between them, rectifier bridge or LLC transformer?

西里古1992

langtuodianzi posted on 2023-2-2 10:01 The gas discharge tube connected in parallel to the common mode inductor has the same function as the ceramic discharge tube connected in series with the varistor across the L phase and the N phase to the ground. Both functions are used to prevent common mode lightning strikes. ...

Therefore, the specification of the lightning protection tube only has current parameters, and there is no corresponding surge, which is the voltage peak parameter of the lightning strike experiment. I don't know how to choose

西里古1992

chunyang posted on 2023-1-31 18:36 The connection method of RV002 and RV003 is wrong. Three TVS should be used, one across the two ends of the protected circuit, and two respectively connected between the protected circuit and the protection ground, ...

But this method does work.

西里古1992

maychang posted on 2023-1-31 20:49 RV002 and RV003 are connected to both sides of the common mode inductor. What does this mean? It is impossible to generate high voltage on the winding of the common mode inductor. This connection is useless...

It is indeed connected in this way. Many projects use it this way.

西里古1992

maychang posted on 2023-1-31 20:49 RV002 and RV003 are connected to both sides of the common mode inductor. What does this mean? It is impossible to generate high voltage on the winding of the common mode inductor. This connection is useless...

RV002 and RV003 are lightning arresters

西里古1992

Sirigu 1992 posted on 2023-2-7 14:56 But this method of connection does work

RV002 and RV003 are lightning arresters

maychang

Sirigu1992 posted on 2023-2-7 14:57 It is indeed accepted in this way, and many projects use this method

[It is indeed connected in this way, and many projects use it this way]

Sign !

chunyang

Sirigu 1992 posted on 2023-2-7 14:56 But this method of connection does work

If you want to connect it this way, you must add TVS to the subsequent stage.

西里古1992

chunyang posted on 2023-2-7 15:30 If you want to connect it this way, you must add TVS to the back stage.

I checked and found none before the rectifier bridge. But RV001 is a varistor, does it need to be added for the follow-up problem of the discharge tube? Is the power supply working voltage > the follow-up voltage of the discharge tube?

chunyang

Sirigu1992 posted on 2023-2-7 15:52 I checked and found none before the rectifier bridge. But RV001 is a varistor, does the discharge tube need to be added for the follow-current problem? The power supply working voltage...

Lightning energy must be released to the protected area. Wherever the lightning energy can reach, a reliable energy release circuit must be set up, otherwise it is meaningless.

西里古1992

langtuodianzi posted on 2023-2-2 10:01 The gas discharge tube connected in parallel to the common mode inductor has the same function as the ceramic discharge tube connected in series with the varistor across the L phase and the N phase to the ground. Both functions are used to prevent common mode lightning strikes. ...

Is it used to prevent common mode lightning strikes? I have seen some explanations that differential mode lightning strikes are caused by the differential mode component of the common mode inductor discharging to raise the voltage of the subsequent circuit, and the discharge tube is used for clamping protection. Does this mean that differential mode lightning strikes are prevented?

西里古1992

chunyang posted on 2023-2-7 16:26 Lightning energy must be released to the protective ground. Wherever the lightning energy can reach, a reliable energy release circuit must be set up, otherwise it is meaningless.

The input circuit is like this, nothing else. I just want to ask about the release path. There is no other place except the Y capacitor.

maychang

Sirigu1992 posted on 2023-2-7 16:58 The input circuit is like this, nothing else. I just want to ask about the release path. There is no other place except the Y capacitor.

The discharge path is at C012 and C014. The discharge tube connected in parallel with the common mode inductor winding should be placed at the position of these two capacitors.

Note the ground symbol between the two capacitors.