Contact force is one of the basic elements of terminal blocks. If there is not enough contact pressure, no matter how good the conductive material is, it will be useless. Because if the contact force is too low, displacement will occur between the wire and the conductive sheet, resulting in oxidation pollution, increasing the contact resistance and causing overheating. Taking the DRTB2.5 clamping frame assembly as an example, only 0.8Nm of torque is applied to the screw to generate an actual contact force of up to 750N, and the magnitude of this force has nothing to do with the wire cross-section. Therefore, the use of the terminal clamping frame has a permanent connection with a large contact area and large contact force that is not affected by any environment. Small voltage drop The voltage drop at the contact point is also one of the criteria for identifying the quality of the terminal block. Even if a small torque is applied to the screw, the voltage drop value is still much lower than the limit required by VDE0611. At the same time, the applied torque varies in a wide range, and the voltage drop is almost unchanged. Therefore, although different operators use different torques, it will not affect the connection quality. This is another proof of the reliability of the clamping frame used in the terminal block. Self-locking function A large contact force is only meaningful if it acts on the wire permanently.

The use of a wire clamp in the terminal also has the greatest reliability in this regard. During the tightening of the screw, the threaded tongue on the wire clamp bounces upward, thereby generating a reaction force on the screw. The change in wire diameter caused by temperature is offset by the elastic effect of the wire clamp itself, so there is no need to tighten the screw again.

If the wire clamp with the wire clamped is subjected to an aging test for 168 hours at 130°C, and then a vibration test for 168 hours at 20 times the acceleration of gravity. After completing these tests that are more stringent than VDE0611, the pull-out force of the wire from the wire clamp is still six times higher than the specified value of VDE0611, and the voltage drop remains unchanged. This clearly shows the maintenance-free nature of the wire clamp used in the terminal. Airtightness Various environmental factors, such as temperature and air humidity, act on the terminal blocks for a long time. Therefore, the terminal blocks must be able to withstand the test of adverse environmental factors. Tests conducted in accordance with the provisions of Chapter 76 of DIN41640 and actual experience have proved that the wire frame can maintain its airtightness even when connecting soft wires without crimping ends.