-Mechanical Parameters-
contact pressure
In most structures, direct measurement of contact pressure is rather difficult. Therefore, the contact pressure is often measured indirectly by the single-foot separation force. For a circular pinhole contact pair, a standard pin with a specified weight is usually used to test the ability of the female contact to hold the weight. Generally, the diameter of the standard pin is -5μm, the lower limit of the diameter of the male contact. The total separation force is generally twice the sum of the upper and lower lines of the single foot separation force. When the total separation force exceeds 50N, it is quite difficult to insert and pull out manually. Of course, for some test equipment or occasions with special requirements, zero insertion force connectors, automatic detachment connectors, etc. can be selected.
Mechanical life
The mechanical life of the connector refers to the insertion and removal life, which is usually specified as 500 to 5000 times. When reaching the specified mechanical life, the contact resistance, insulation resistance and withstand voltage of the connector should not exceed the specified values. Strictly speaking, the current mechanical life is a vague concept. The mechanical life should have a certain relationship with time. Obviously, the situation is different when it is used up 500 times in 10 years and 500 times in 1 year. It’s just that there is no more economical and scientific way to measure it.
Number of Contact Pairs and Pinholes
The number of contact pairs can be selected according to the needs of the circuit, taking into account the size of the connector and the total separation force. The larger the number of contact pairs, the larger the volume and the larger the total separation force. In some cases where the reliability is high and the volume is allowed, the method of connecting two pairs of contact pairs in parallel can be used to improve the reliability of the connection. In the plug and socket of the connector, the pins (male contacts) and jacks (female contacts) can generally be assembled interchangeably. In actual use, it can be selected according to the live condition of both ends of the plug and socket. If the socket needs to be charged frequently, you can choose a socket with a jack, because the live contact of the socket with a jack is buried in the insulator, and it is not easy for the human body to touch the live contact, which is relatively safe.
Vibration, shock, collision
The electrical continuity of the contact pair when the connector is vibrated, impacted, and collided under the specified frequency and acceleration conditions is mainly considered. The contact pair will open instantaneously under this dynamic stress condition. The specified transient time is generally 1μs, 10μs, 100μs, 1ms and 10ms. The thing to pay attention to is how to judge the momentary failure of the contact pair. It is now generally believed that when the voltage drop across the closed contact pair (contacts) exceeds 50% of the power supply electromotive force, it can be determined that the closed contact pair (contacts) fails. That is to say, there are two conditions for judging whether an instantaneous interruption occurs: duration and voltage drop, both of which are indispensable.
Connection method
The connector is generally composed of a plug and a socket, in which the plug is also called a free end connector, and the socket is also called a fixed connector. The connection and disconnection of the circuit is realized by the insertion and separation of the plug and the socket, so various connection methods of the plug and the socket are produced. For circular connectors, there are mainly three ways: threaded connection, bayonet connection and self-locking (ball) connection. Among them, the threaded connection is the most common. It has the advantages of simple processing technology, low manufacturing cost and wide application range, but the connection speed is slow and it is not suitable for occasions requiring frequent plugging and quick connection. The bayonet type connection has a faster connection speed due to the longer lead of its three bayonet slots, but it is more complicated to manufacture and the cost is higher. The self-locking (ball) connection is the fastest connection among the three connection methods. It does not need to perform rotational movement, but only needs to perform linear movement to realize the functions of connection, separation and locking. Since it is a push-pull connection, it is only suitable for connectors with low total separation force. Generally more common in small connectors.
Installation method and shape
The installation of the connector includes front installation and rear installation, and the installation and fixing methods include rivets, screws, collars or quick locking of the connector itself. There is also a plug and socket that are both free-end connectors, the so-called relay connectors. The shape of the connector is ever-changing, and the user mainly chooses from the straight, curved, outer diameter of the wire or cable and the fixing requirements with the shell, volume, weight, whether it needs to be connected to a metal hose, etc. Connectors should also be selected from aspects such as appearance, shape, and color.