The mechanical life of a line board connector refers to the insertion/extraction life, typically specified between 499 to 999 cycles. Upon reaching this specified mechanical life, the connector's contact resistance, insulation resistance, and voltage withstand ratings should not exceed the set values. To be precise, the current mechanical life is a somewhat ambiguous concept. The mechanical life should be related to time, although there isn't yet a more economical or scientific method to measure it.
In connector plugs and sockets, the positive contact pieces and negative contact pieces are generally interchangeable. During actual use, selection can be based on the electrified status at both ends of the plug and socket. If the socket needs to be continuously electrified, it's advisable to choose a socket with holes, as the electrified contact pieces in these sockets are embedded within the insulator, making them less accessible to the human touch and thus relatively safer.
The number of contact pairs should be selected based on the circuit requirements, while also considering the connector's size and the total separation force. More contact pairs naturally result in a larger volume and a greater total separation force. In cases where high reliability is required and volume is permitted, paralleling two contact pairs can be used to enhance the connection's reliability.
The primary consideration is the electrical continuity of the contact pair under vibration, shock, and collision at specified frequencies and accelerations. In this dynamic stress condition, the contact pair may experience an instantaneous open circuit. The specified instantaneous break time generally ranges from 1μs to 100μs, or 1ms to 10ms. It is important to note how to determine if a contact pair has an instantaneous break fault. It is now generally believed that when the voltage drop across both ends of a closed contact pair exceeds 50% of the source electromotive force, a fault in the closed contact pair can be deemed to have occurred. In other words, determining if an instantaneous break has occurred requires two conditions: duration and voltage drop, neither of which can be absent.
