Environmental and mechanical influences within switchgear place increased demands on the mechanical resilience and quality of the respective components and their connection areas. With regard to terminal blocks, these specific requirements are defined in international norms and standards and the resulting test procedures. They refer to the terminal body and the insulating housing, as well as to the safe connection capacity and the resistance of the terminal block with regard to wire rotation and conductor pull-out.
Quality, reliability and high standards are the focus of our mechanical testing. Learn more about how we test the quality and mechanical properties of our products and successfully withstand the challenges of industrial environments.
Proof of the mechanical strength of the connection points ensures the mechanical and electrical contact reliability of the connection point. Thereby, the mechanical stability is assessed via multiple wiring of the connection point and, in addition, the electrical contact reliability is assessed via a measurement of the voltage drop.
For the test, 5 terminal blocks are lined up on a DIN rail conforming to the standard. The wires with the rated cross-section of the terminal block are connected and disconnected five times. A new conductor is used after each disconnection and the voltage drop is measured before and after connection.
The test is considered to be passed if the measured voltage drop across the terminal block, before and after the test, does not exceed the required limits.
The proof of installation of the terminal block on its mounting support ensures that the terminal block is firmly seated on the standardized DIN rail. The required test force is applied to the terminal block via the connection point.
For the test, terminal blocks are mounted on a DIN rail. Depending on the cross-section, a standardized steel rod with a defined diameter is fixed in the clamping points. Cross-section-dependent forces act on the terminal block over a lever distance of 100 mm.
The test is considered to be passed if the terminal blocks do not detach from the DIN rail or show any other damage.
Testing for damage to and accidental loosening of conductors of a terminal block proves both the high mechanical safety and the reliable connection of the wire. The test is divided into two successive parts - the flexion test and a following pull out test.
For the flexion test, one end of the wire is connected in the connection point of the terminal block. A standardized test weight is attached to the other end of the wire so that it can swing freely. The test then provides for a rotation of 135 turns with a defined radius without any interruption.
The test is considered to be passed if, during and also after the subsequent wire pull-out test, the wire neither slips out of the connection point nor breaks in the vicinity of the connection point.
Testing for damage to and accidental loosening of conductors of a terminal block proves both the high mechanical safety and the reliable connection of the wire. The test is divided into two successive parts - the flexion test and a following pull out test.
For the pull out test, one end of the wire is attached to the terminal block and the other end is attached to the pull out testing machine. Depending on the cross-section of the wire, the standard requires a defined pulling force over 60 seconds.
The test is considered to be passed if, during the flexion test and the subsequent pull-out test of the wire, the wire neither moves out of the connection point nor breaks in the area of the connection point.
The proof of the plug-in cycles ensures the contact quality over the service life of a plug-in contact. Since the terminal block standard IEC 60947-7-1/-2/-3 does not specify any requirements for mating cycles with regard to pluggable terminal blocks, these are tested on the basis of the connector standard IEC 61984.
For the test, pluggable terminal blocks including plugs are mounted on a standard-compliant DIN rail. With a speed of 3-4 plug-in cycles per minute, the service life test is simulated.
The test is considered to be passed if there is no damage to the terminal block including the plug connection and further use is guaranteed. Furthermore, at the end of the test, the measured voltage drop must comply with the specified values.
The proof of connection capability ensures that the documented wire cross-sections can be connected. Here, only the insertability of the wire in the connection point is checked. The tested wire cross-sections are ultimately documented in metric (mm²) and Anglo-American values (AWG).
For the test, the insertability of the rated cross-section and the two next smaller wire cross-sections are checked. As an alternative to the respective wires, proof can also be provided by means of a standardized gauge.
The test is considered to be passed if the wire or the gauge can be inserted unhindered in the connection point.
The proof of touch-safe protection ensures protection against direct (accidental) contact. The IP degree of protection, for example IP40 against direct contact, refers to the enclosure of electrical switchgear and not to the installation components such as terminal blocks. The design of the terminal blocks takes into account the so-called finger safety and back-of-hand safety according to IEC 60529. Verification is performed by the articulated test finger or test ball according to IEC 61032.
For the test, Weidmüller normally installs 10 terminal blocks on a standard-compliant DIN rail and wires the terminal points with the rated cross-section. Following this, the test is carried out with reference to the test finger or test ball.
Finger safety according to IEC 60529 is given if the articulated test finger according to IEC 61032 cannot touch any parts at risk of contact in all actuation directions. The articulated test finger applies a test force of 10 N to the terminal block. This may enter up to its 80 mm length and not touch any dangerous live parts.
The test is considered to be passed if the test finger or the test ball cannot touch any live parts. This ensures protection against unintended contact in accordance with IEC 60529 IPXXB or IPXXA.
Back-of-hand safety according to IEC 60529 is given if a ball with a diameter of 50 mm according to IEC 61032 with a force of 50 (± 5) N does not touch any live parts.
The test is considered to be passed if the test finger or the test ball cannot touch any live parts. This ensures protection against unintended contact in accordance with IEC 60529 IPXXB or IPXXA.
The proof of the respective shock and vibration tests ensures the safe use of the terminal blocks and the contact reliability under the mentioned fault influences. Electrical switchgear and its installed individual components are exposed to various vibrations and shocks in many industries. For example, in railway vehicles or rotating machines and drives. In the laboratory, shocks and vibrations can be applied to the test setup and simulated using a " vibration table ".
For the tests, terminal blocks are mounted on a standard-compliant DIN rail and the terminal connection points are wired with the rated cross-section. The DIN rail is mechanically fixed on the vibrating table, so that the shocks and vibrations are directly transmitted to the terminal rail.
The category 1b test defines an acceleration with an effective value of 5.72 m/s² and a frequency range from 5 Hz to 150 Hz. The simulation moves the test setup for 5 hours in all three axes (x, y, z).
The test is considered to be passed if there is no damage to the terminal block and further use is guaranteed.
The test simulates an acceleration with the effective value of 50 m/s² and a frequency range from 5 Hz to 150 Hz. This frequency range increases by one octave every minute. The simulation moves the test setup for 2 hours in all three axes (x, y, z).
The test is considered to be passed if there is no damage to the terminal block and further use is guaranteed.
The test setup experiences an acceleration of 50 m/s² with a shock duration of 30 ms. Furthermore, IEC 60068-2-27 requires three positive and negative shocks (18 total) in each of the three axes (x, y, z).
The test is considered to be passed if there is no damage to the terminal block and further use is guaranteed.
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