EN 61000-4-4-1995 pdf download.Electromagnetic compatibility (EMC) Part 4. 11st1ng and measurement techniques Section 4. Electrical fast transient/burst immunity test — Basic EMC publication.
6.3 CapacItive coupling cLamp
The clamp provides the ability of coupling the fast transientslbursts to the circuit under test without any galvanic connection to the terminals of the EUTs ports, shielding of the cables or any other part of the EUT.
The coupling capacitance of the clamp depends on the diameter, material of the cables. and shielding (I any).
The device is composed of a clamp unit (made of galvanized steel, brass, copper or aluminium) for housing the cables (flat or round) of the circuits under test and shall be placed on a ground plane of minimum area of 1 m’. The reference ground plane shall extend beyond the clamp by a least 0,1 m on all sides.
The line shall be provided at both ends with a high-voltage coaxial connector for the connection of the test generator at either end. The generator shall be connected to that end of the clamp which Is nearest to the EUT.
The clamp itself shall be closed as much as possIble to provide maximum coupling capacitance between the cable and the clamp
The recommended mechanical arrangement of the coupling clamp is given in fIgure 5 and determines its characteristics, such as frequency response, impedance. etc.
Characteristics
— typical coupling capacitance
between cable and clamp: 50 pF to 200 pF;
— usable diameter range of round cables: 4 mm to 40 mm;
— insulation withstand capability: 5 kV (test-pulse: 1.2/50 ps).
The coupling method ussng the clamp is required for acceptance tests. it is designed to be used on lines connected to 110 and communication ports, but also on a.cld.c. power supply ports if the coupling/decoupling network defined in 6.2 cannot be used. Other coupling methods (e.g. coupling/decoupling networks) may be used according to the product standard.
7 T.st set.up
Two different types of tests can be Oshnguished:
– type tests performed In laboratories:
— post-installation tests performed on equipment in Its final installed conditions.
The preferred test method is that of type tests performed In laboratories.
The EUT shall be arranged in accordance with the manufacturers Instructions for installation (If any).
7.1 Test equipment
The test set-up Includes the following equipment (see figure 6):
– ground reference plane:
— coupling device (network or clamp);
— decoupling network:
— test generator. including the calibration or measurement means.
7.2 Test set-up for type tests p.ilormed in 1aboratores
7.2.1 Test conditions
The following requirements apply to tests performed In laboratories under the environmental reference conditions outlined in 8.1.
The EUTs shall be placed on a ground reference plane and sha’l be insulated from It by an insulating supporl 0.1 m * 0,01 m thick.
The reference ground plane shall be connected to the protective earth (ground in US terminology).
The EUT shall be arranged and connected to satisfy Its functional requirements, according to m. equipment Installation specifications.
The minimum distance between the EUT and all other conductive structures (e.g. the walls of a shielded room), except the ground plane beneath the EUT. shall be more than 0.5 m.
The EUT shall be connected to the earthing system in accordance with the manufacturers installation specIfecations: no additional earthing connections are allowed.
The connection of the test equipment ground cables to the ground reference plane and all bondings shall provide minimum Inductance.
Coupling devices shall be used for the application of the test voltages. They shall be coupled to the lines between the EUT and the decouplIng network or between two units of equipment Involved In the test.
Using th• coupling damp, the minimum distance between the coupling plates and all other conductive structures, except the ground plane beneath the coupling clamp and beneath the EUT. shall be 0.5 m.
The length of the signal and power lines between the coupling device and the EUT shall be 1 m or less.
If the manufacturer povldes a non-detachable supply cable more than I m long with the equipmnt, the excess length of this cable shall be gathered Into a flat coil with a 0,4 m diameter and situated at a distance of 0.1 m above the ground reference plane. The distance of I m or less between EUT and the coupling device shall be ma’ntalned.
Examples of the test set-up for laboratory tests are given in figure 7.
7.22 Methods of coupling the test voltage to the EIJT
The test voltage shall be applied to the following different types of lines or ports of the EUT:
Power supply ports.EN 61000-4-4-1995 pdf download.