82
A
Leakage Current Tester 92-4A, -4D, -4E, -4G
BASIC TEST MODES
VI.ix Measuring of contact currents according UL250 / UL471
The measuring of the contact current is carried out according the network
shown below. The contact current have to observe the values predefined
in the UL-standard. A detailed description of the prerequisites for the
measuring contains the
UL250 / UL471
-standard.
Wiring diagram:
Measuring network:
Circuit conditions for 1 phase test objects.
A1 - normal polarity with N-fault (S1 and S2 not active)
A2 - inverse polarity with N-fault (S1 not active, S2 active)
A3 - normal polarity in operation without fault (S1 active, S2 not
active)
A4 - inverse polarity in operation without fault (S1 and S2 active)
test contacts
V
U1
1500
Ohm
A
B
150nF
