Hv Dielectric Test (Withstanding Voltage Test) - LEM MachineTest 204 Manuel D'utilisation

MEASUREMENTS

4.4 HV Dielectric test (withstanding voltage test)

Measurement principle
230 V
50 Hz
Fig. 17: Principle: HV Dielectric test
Practical measurement
Warnings!
Make sure tested object to be disconnected from mains voltage!
-
Dangerous measurement! Test voltage of over 1000 V AC supplied
-
by 500 VA transformer is applied to test tips!
Make sure there is no third party person around the tested object
-
when the test is being carried out and national safety requirements
are fulfilled (e.g.: DIN VDE 0104) !
How to carry out the measurement
STEP 1 Prepare the machine to be tested
Assure tested object to be disconnected from mains voltage.
-
Switch "on" main switch of tested object as well as other switches, in
-
order all electronic parts of tested object to be included in the test!
- Short all live terminals of tested object (L1, L2, L3, N).
Check electric circuit diagram of the machine or the machine itself with
-
regard to mains part connection. There may be some capacitors
connected between live parts (L1, L2, L3, N) and PE terminal (housing)
which serve as EMC filter or noise suppressor etc., see the figure below.
In case the capacitors are not rated for AC voltage of up to 1000 V, take
care to remove them before carrying out the test otherwise they may be
damaged. If the capacitors are rated for voltages of up to 1000 V AC then
they may remain in place if their capacitance is not too high (capacitive
current can not be compensated if the capacitance is too high), see the
next table.
A
1000 V
short all
live parts
_
∼
min. 1s!
V
+
∼
19
L1
L2
L3
N
PE
PE collector