UL 497A
R1
50,000 Ω
25 W
R2
10 Ω
5W
C1
V
Variable DC Supply
0-1000 V
Test
Specimen
Figure 4.10 UL 497A Breakdown Voltage Measurement Test
Circuit for Common Mode (Longitudinal)
Overvoltage Tests
Current
Limiting
Resistors
Secondary Protector
Simulator or
Wiring Station
Equipment
Under Test
Timed
Switch
Variable
AC Voltage
Source
Equipment
Ground
Figure 4.11 UL 497A Overvoltage Test
Circuit for Differential Mode (Metallic)
Overvoltage Tests
Current
Limiting
Resistor
Secondary Protector
Simulator or
Wiring Station
Timed
Switch
Variable
Voltage
Source
Telecommunication
Network Connection
Points
Equipment
Under Test
Equipment
Ground
Equipment
Ground
© 2002 Teccor Electronics
SIDACtor® Data Book and Design Guide
4 - 29
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