UL 497A
R1
R2
10 Ω
5 W
50,000 Ω
25 W
C1
V
Test
Specimen
Variable DC Supply
0-1000 V
Figure 4.10 UL 497A Breakdown Voltage Measurement Test
Circuit for Common Mode (Longitudinal)
Overvoltage Tests
Circuit for Differential Mode (Metallic)
Overvoltage Tests
Current
Secondary Protector
Simulator or
Limiting
Resistors
Current
Limiting
Resistor
Wiring Station
Secondary Protector
Simulator or
Wiring Station
Equipment
Under Test
Telecommunication
Network Connection
Points
Equipment
Under Test
Timed
Switch
Timed
Switch
Variable
Voltage
Source
Variable
AC Voltage
Source
Equipment
Ground
Equipment
Ground
Equipment
Ground
Figure 4.11 UL 497A Overvoltage Test
© 2002 Teccor Electronics
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