Pressure switch contact system

Pressure switch contact system
For type electromagnetic switch contact is its executive mechanism, is used to connect or disconnect the circuit, the reliability of the switch work and life, to a great extent, depends on how well contact work.Therefore, must pay full attention to this problem, in order to properly design, manufacture and use, for the power industry to provide the most reliable control and protection switch.
Switch contact form is divided into a lot of kinds, but the commonly used have move close contact (g -), and dynamic fracture (normally closed) contact, etc., in order to correctly understand, first put a brief explanation of the above two terms:
Dynamic contact (or "normally open contacts) is defined as: under normal circumstances, contact is open.The so-called normal situation, is refers to the switch before action.Switch coil, for example, before is not exciting, its contact if in the open position, then the contact is called dynamic contact.    
Move off contact, or normally closed contacts) is defined as: under normal circumstances, contact is closed.
The working state of the contact is four: closed, opening process, disconnected, closing process.Basic requirements for the work of it, is simply stated: "points" in a reliable way, reliable "close".Ideally, the contact is in a state of closure is best can like a whole piece of conductor;Disconnect immediately goes to zero when the current;Closed circuit immediately when the normal conduction;In the off state have good insulation performance, can withstand the high voltage.But, just in the contacts on and off (and) so simple in the form of exercise, has many special physical and chemical phenomena happened., for example, when closed conductive contact part of the total contact resistance exists, when this resistance to a certain degree can lead to power;When the breaker is often accompanied by arc or spark, serious when can cause the switch to cut and constantly or the protected equipment burned;Produces in the process of closing the mechanical collision, make contact bounce and appear a series of very short arc, even make contact welding together;In the disconnected state if the insulation strength is not enough, may be over voltage breakdown again.Below will be the first to the different working conditions according to the contact to analyze the contradiction in all stages of work nature, and then to sum up, analysis of the overall problem.

The above: Pressure switches' performance requirements