What is the Aviation Connector（1）

Aviation connectors, also known as Harsh Environment Connectors plugs, is aviation connector, i.e., cable connector. The number of cores is different, and the size is variable. But basically, they are metal housings with screw fasteners for the plugs and sockets. They can be fixed and secured when connected and will not come off.

It is in use and named on aircraft. It finds widespread use in navigation, aerospace, and electrical applications. The housing material is usually made of strong and durable magnesium-aluminum alloy. Sockets and plugs are complementary. The main difference is that one is male and the other is female.

Airline socket is called, respectively, airline plug, connector, connector, airline plug, etc. Their main function is to connect easily. They are mainly for signaling and power connections. Push-pull self-locking and threaded screw connections are available. The protection level is IP44, IP55, IP65, IP67, IP68, and IP69. The higher the protection level, the better the waterproof performance, generally used in various communication equipment and instrumentation.

The only difference is that the air plug is suitable for industrial electricity use. This is because it bears a higher voltage. Some consist of high-voltage electrical conversions that only air plugs can satisfy. The general power plug can not meet the voltage requirements.

• Types of aviation plugs: single-phase plugs, three-phase plugs.
• Single-phase aviation plug points: single-phase two-pole plug, single-phase grounding plug (single-phase three-stage plug).
• Three-phase aviation plug power plug: three-phase four-stage plug.
• The structure of the plug: copper (dynamic contact), terminals, plastic shell, screws, and other components.
• The symbol of the plug: XP single-phase single-stage plug symbol.
• Single-phase plugs of the contacts to distinguish the method. Plug the contacts of the discriminatory method, and the discriminatory method of the socket is the opposite. That is the “left fire right zero”. The left contact connects to the firewire. The right contact connects to the zero (N) wire, and the middle contact connects to the ground wire.
• The rated voltage of the plug: single-phase poke head rated voltage of 220V. Three-phase plug rated voltage of 380V.

Air Plug Structure Characteristics

• According to the installation mode: mobile type, open type, concealed type
• According to whether the socket has an interlocking device, without interlock, with mechanical interlock, with electrical interlock.
• According to whether the socket is with safety transformer or not: without a transformer, with transformer.
• According to whether the socket has a safety transformer or not: without a transformer, with a transformer.

Parameter Requirements of Aviation Connector

Aviation connector is electromechanical components connected to electrical circuits. Therefore, the electrical parameters of the aviation connector itself are the first thing to consider when choosing the aviation connector.

1. Rated Voltage

Rated voltage is also called working voltage. It mainly depends on the insulation material used in the aviation plug and the size of the spacing between the contact pairs. Some components or devices may not be able to complete their proper functions when the voltage is lower than their rated voltage. The rated voltage of the aviation plug should understand the maximum working voltage recommended by the manufacturer.

In principle, the aviation plugs can work properly at voltages lower than the rated voltage. That is to say, the same withstand voltage index, according to different use environments and safety requirements can use different maximum working voltage. This is also more in line with the objective use of the situation.

2. Rated Current

Rated current is also known as the working current. Like the rated voltage, the aviation plug can generally work properly in the case of lower than the rated current. The design process of the aerial plug is to meet the rated current requirements through the thermal design of the aerial plug. This is because the contact pair will become heated in a contact pair with current flow due to the conductor and contact resistance.

When its heat generation exceeds a certain limit, it will destroy the insulation of the air plug and form the softening of the surface coating of the contact pair, causing failure. Therefore, to limit the rated current, the temperature rise inside the airline plug does not exceed the value specified in the design.

The issue to remember when selecting is that for multi-core aviation plugs, the rated current must apply when derating. This should pay more attention to the occasion of high current, for example, φ3.5mm contact pair, the general provisions of its rated current of 50A, but in 5 cores to derate 33% of the use, that is, the rated current of each core is only 38A, the more cores, the greater the range of derating.

3. Contact Resistance

Contact resistance refers to the resistance of the two contact conductors in the contact section. In the selection of two issues to note, first, the contact resistance of the aviation plug indicator is, in fact, the contact to resistance, which includes contact resistance and contact to conductor resistance.

Usually, the conductor resistance is small, so the contact pair resistance is called contact resistance in many technical specifications. Second, in circuits connected to small signals, it is important to note the conditions under which the given contact resistance indicator is tested because the contact surface will be attached to the oxide layer, oil, or other contaminants. The surface of the two contact parts will produce a film layer resistance.

When the thickness of the film increases, the resistance increases rapidly, and the film becomes a poor conductor. However, mechanical breakdown of the film can occur at high contact pressures or electrical breakdown at high voltages and currents. For some small volumes, the design of the connector has a fairly low contact pressure, using only milliamp and millivolt levels. The resistance of the membrane does not break easily, which may affect the transmission of electrical signals.

In GB5095, “basic test procedures and measurement methods for electromechanical components used in electrical equipment,” one of the contact resistance test methods, “contact resistance – millivolt method,” has been set.

To prevent damage to the insulation film on the contacts, the DC or AC peak potential of the open circuit electric potential of the test circuit should not be greater than 20mV, and the DC or AC test current should not be greater than 100mA. This is a low-level contact resistance test method. Therefore, the choice of this requirement is due to the use of low-level contact resistance indicators by the aviation plug.

4. Shielding

In modern electrical and electronic equipment, the density of components and the increasing number of related functions between them, electromagnetic interference put forward a strict limit. So aviation plugs usually close metal shells to stop the internal electromagnetic energy radiation or external electromagnetic field interference.

At low frequencies, only magnetic materials can play a significant role in shielding the magnetic field. At this time, there are certain regulations on the electrical continuity of the metal shell, which is the shell contact resistance.

The Advantages of Aviation Connector

Aviation plugs are everywhere today. What are the benefits of using aviation plugs?

1. Easy to Repair

If an electronic component fails, equipped with an aviation plug can quickly replace the failed components.

2. Improve the Production Process

The use of aviation plugs simplifies the assembly process of electronic products and also simplifies the process of mass production.

3. Easy to Upgrade

As technology advances, it is possible to replace new parts when equipping air plugs, replacing old parts with new, more complete ones.

4. Improve Design Flexibility

The use of aerial plugs allows engineers to design and integrate new products, as well as the use of components to form the system. There is greater flexibility because the structure of the aerial plug is increasingly diverse, new structures and applications continue to emerge, and trying to use a fixed model to solve the problem of classification and naming, has appeared difficult to adapt.