What are the basic properties of wiring terminals? The basic performance of terminal blocks can generally be divided into three categories: mechanical performance, electrical performance, and environmental performance.
1、 Mechanical performance testing
1. Tightening Torque Test
The purpose of torque testing is to test whether the screw has sufficient mechanical strength to ensure that there is no slippage during the wire pressing process. If the screw does not break or deform after testing, and there is no damage to the screw head groove that affects continued use, it is qualified.
2. Wiring Reliability Test （Secureness TeST）
The purpose of the crimping reliability test is to test whether the terminal can clamp the wire without excessively damaging the wire. Connect a wire of the specified type and rated cross-sectional area to the terminal, hang a certain weight, and rotate at a speed of 10 revolutions per minute （10 ± 2r/min） for 15 minutes. After testing, if the wire does not slide out of the terminal clamp or break near the clamp, the reliability of the terminal crimping is qualified. If there is a wire breakage or detachment from the clamping mechanism of the terminal, it is unqualified.
3. Pull Out Test
The purpose of the pull-out test is to test whether the terminal can firmly clamp the wire between the metal surfaces. Connect the wire of the specified type and rated cross-sectional area to the terminal, apply a certain force （lkgf）， and pull the wire towards the axis direction of the wire for 1 minute. If the wire does not detach from the terminal, it is qualified.
4. Mechanical Strength Test
The purpose of mechanical strength testing is to test whether the terminal has sufficient mechanical strength, especially to test whether the outer shell of the terminal has sufficient mechanical strength. During the testing process, place one sample into the drum of the testing equipment and rotate it at a speed of 5 revolutions per minute for 5 minutes. After turning off the machine and taking out the sample for observation, if the terminal is not damaged and the shell is not cracked or damaged, it is considered qualified.
5. Fatigue Test for Mechanical Life
The purpose of mechanical life testing is to test whether the elastic components of the terminal can withstand a certain number of insertions or other mechanical operations, such as the compression and release of spring type terminal buttons. If the tested elastic component is assembled into the terminal and its mechanical and electrical performance still meets the requirements, it is qualified.
2、 Electrical performance testing
1. Contact Resistance Test
The contact resistance test is to test the static contact performance of the terminal, that is, the contact resistance should not exceed a certain value.
2. Power Frequency Withstand Voltage Test
The power frequency withstand voltage test is to test whether the terminal housing can withstand the specified transient or short-term power frequency overvoltage. During the experiment, there shall be no flashover or breakdown phenomena.
3. Impulse Withstand Voltage Test
The impulse withstand voltage test is to test whether the terminal housing can withstand the specified transient overvoltage. There should be no destructive discharge during the experiment.
4. Voltage Drop Test
Voltage drop test is used to test the dynamic contact performance of terminals. The voltage drop should not exceed a certain value.
5. Temperature Rise Test
The temperature rise test is to test that the temperature rise of the terminal cannot exceed the specified value during normal use. Generally, UL standards stipulate that the temperature rise of the terminal after passing current cannot exceed 30 ℃ of the ambient temperature.
6. Electrical Performance Test for High and Low Temperature
Electrical performance test is to test the reliability of the electrical performance of non threaded terminals during normal use. After 192 cycles, the voltage drop of the terminal in the 24th and last cycles shall not exceed a certain value.
3、 Environmental performance testing
1. Vibration Test for Package
The packaging vibration test simulates the ability of the terminal packaging to withstand vibrations during transportation. After testing, the terminals inside the packaging must not be affected or damaged.
2. Vibration Test for Products
The product vibration test simulates the ability of a terminal to withstand vibration during use. Fix the terminals on the vibration table in sequence, including front, back, left, right, top, and bottom. Apply specified analog signals to the X, Y, and Z axes of the terminals, and after testing, the terminals must not be damaged.
3. Test for Flammability of Plastic Materials
Flame retardant test is to test the flame retardant performance of terminal materials. During the testing process, clamp the standard sample strip onto the clamping seat of the instrument, move the fire source to the designated position, ignite and burn for the specified time, and then remove the fire source. If the sample strip still burns or its droplets ignite the cotton below the sample strip after the fire source is removed, the flame retardancy is unqualified. If the sample strip extinguishes on its own after the fire source is removed, the flame retardancy is qualified.
4. Resistance Aging Test
The aging resistance test is to test whether the terminal can be used normally at a certain high temperature. Place the terminal in the aging test chamber and apply a high temperature of 105 ℃ or 120 ℃ for 7 days. If the tested terminal does not age, it is considered qualified.
5. Damp Heat Test
The alternating humidity test is used to test whether a terminal can withstand the humid conditions that may occur during normal use.
6. Salt Spray Test
Salt spray test is also used to test whether the terminal can withstand the humid conditions that may occur during normal use. If the metal components of the terminal are tested separately and rust appears, it is considered unqualified.
