Q&A Lightning Surge Simulators (Model: LSS series)
Phase placement (this Q&A is not applicable LSSF02/F03 series)
Q1. 
We are a user of the LSS15AX surge simulator. What is the reference for the line synchronization？Can the desired phase angle placement of the surge be selected for each line of 3phase system?


Surge placement on the EUT AC line phase angle is shown and done based on L1L2 reference. Therefore, corrections on settings shall be done for each line, as follows: add 120 degrees for L2L3, 240 degrees for L3L1, 30 degrees for L1N, 150 degrees for L2N, 270 degrees for L3N. For placement at 90 degrees, the following values shall be set on the LSS:
L1L2 90°
L2L3 210°
L3L1 330°
L1N 120°
L2N 240
L3N 0° (=360°)
L1PE 120°
L2PE 240°
L3PE 0°
Since theoretically there is no relationship of phase between each phase of power lines and PE, the setup compensation value of common mode injection cannot be defined. However, in the actual wiring, i.e. in the connection of route of power supply  external insulation transformer  surge simulator, the decoupling capacitor (10μF) of the surge simulator is connected between each line and PE. This capacitor is balancing each line and acts like making the PE the middle point.
And, besides, since the N phase is also the middle point, the phase relationship between linePE is equivalent to that between lineN. After installing this simulator, observe the actual output, and confirm before testing whether the phase relationship between linePE is equivalent to that between lineN or not.



















