EMC-PARTNER CDN2000-06-25, User Manual

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E-CDN2000-06-25-E-Manual 35/54
8 What must be done following failed operation
8.1 Service; Repairs
The CDN2000-06-25 is a compact equipment and servicing or repairing the tester can only be carried out by
EMC PARTNER authorised service companies.
8.2 Spare parts list
No spare parts are necessary for the MIG.
8.3 Hints when varistors have been damaged in a CDN
8.3.1 General
1) For correct and repeatable test results the CDN input potentially must be fixed (varistors and filters) as
shown in the drawing attached.
2) The varistor can not be destroyed by a SURGE. The energy of the SURGE generator into the varistor is
limited by the generator, coupling impedance and the decoupling coils 1.8mH
3) The varistor can only be destroyed by too high power line voltage and continuous a.c. current passing
the varistors. Below are the reasons listed, why too high power line voltages can occur across the
varistors:
a) Too high voltage at the input of the CDN e.g. instead of 440V a 690V is connected at the CDN input
b) N is not connected to PE. Continuous voltage > 300V caused by unsymmetrical loads will destroy
varistors between N to PE
c) Unbalanced voltages caused by heavy unsymmetrical EUT loads e.g. 1 phase short circuited,
generate > 300V L to N
d) Unbalanced power supply caused by heavy load equipment (e.g. short circuit on one phase) on
same power supply as the CDN
4) Over 250 CDN from EMCP working fine without any problem over many years.
8.3.2 What can be done after varistors has been destroyed?
When a problem with a standard 480V CDN occurs, please check the following:
1) Measure with a multimeter the power supply voltages (CDN not connected)
a) Lx to L <= 480V rms + 8%
b) Lx to N <= 480V / 1.732 <= 277V rms + 8%
c) L to PE <= 480V / 1.732 <= 277 V rms + 8%
d) N to PE =0V
2) When N to PE shows some volts make a connection between N and PE and either measure the current
in the cable or check whether the cable get warm
3) When the cable is cold (no current) make a connection N to PE at the CDN input with 4 mm banana
plugged cable
4) Replace the varistors. Varistors sets can be ordered from EMCP reps.
5) For correct test set-up see user manual of the used CDN
6) Connect always first the PE, second N, last the L
7) For further analysis please send the following information to EMCP PARTNER: Generator setting and
test sequence any load information.
More information can be found in the attached drawing page 2 and in the user manual