Why should the high voltage relay be filled with gas? What is the arc extinguishing principle of gas? Filled with sulfur hexafluoride gas, including hydrogen and nitrogen. The main difference between DC and AC is that DC has no zero crossing point. Once an arc is formed, it will not extinguish itself and will continue to burn. This is fatal damage to the contact! What is the essence of Arc? It is the escape of electrons under the action of electric field force. It is an extreme discharge. Therefore, there are two methods for arc extinguishing, one of which is to increase the contact clearance (the essence of magnetic arc extinguishing is to use Lorentz force to change the arc path, which can be understood as increasing the contact clearance. If the contact clearance is only increased physically without magnetic arc extinguishing, the corresponding relay magnetic clearance should also be large, and the volume and weight are unimaginable under the same load capacity), Another way is to have a substance between the contacts, which can block the path of electrons. The best way to think of is to fill gas. The first requirement is that the gas is very active. If the gas is active, it is easier to collide with the electrons escaping from the arc, resulting in blocking effect and easier to take away heat. Second, it requires that the molecular structure of the gas itself is very stable, and its own electrons are not easy to escape. According to the above two requirements, it is natural to think that hydrogen is the preferred gas for arc extinguishing. The molecular weight of hydrogen is the smallest and most active among all gases, and the molecular structure is stable enough. So this is the technical route of Putian cas-gtvac, because they follow the route of vacuum packaging. Why don't te fill with nitrogen instead of hydrogen, because they are encapsulated in epoxy resin. Hydrogen is the best arc extinguishing gas, but its molecular weight is small. To seal it so that it does not leak, epoxy resin can not do it, so we can only choose nitrogen next.
