SIDACtor® Protection Thyristors UL 497B

SIDACtor ® Protection Thyristors
UL 497B
UL 497B
UL 497B provides requirements for protectors used in
communication and fire alarm circuits. This standard does
not cover devices for primary protection or protection
devices used on telephone lines. SIDACtor® devices are
components recognized in accordance with UL 497B under
UL file number E133083.
Performance Requirements Specific to
SIDACtor® Devices
Construction and Performance Requirements
2. Endurance Conditioning—Protectors are subjected to
50 impulse cycles. Each cycle is a 1000 V peak, 10 A,
10x1000 μs pulse. Pulses are applied in one polarity at
10-second intervals and then repeated in the opposite
polarity.
1. Strike Voltage Breakdown Test—Protectors are
required to break down within the manufacturer’s
specified breakdown range or within 10% of a nominal
single breakdown voltage rating. (Figure 3.17)
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3. Variable Ambient Conditioning—Protectors must
comply with the strike voltage requirements after being
subjected to an ambient temperature of 0 °C for four
hours and again after being subjected to an ambient
temperature of 49 °C for an additional four hours.
4. Discharge Test—Protectors must comply with strike
voltage requirements after being subjected to five
successive discharges from a 2 μF capacitor charged to
1000 V dc. (Figure 3.18)
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requirements:
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5. Repeated Discharge Test—Protectors must not break
down at a voltage higher than the manufacturer’s
maximum rated breakdown voltage nor lower than
rated stand-off voltage after being subjected to 500
discharges from a 0.001 μF capacitor charged to 10,000
V dc. The discharges are applied in five-second intervals
between one side of the protector and Ground. Upon
completion of the discharge tests, protectors are once
again required to meet the strike voltage requirement.
(Figure 3.18)
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Note : The epoxy used to construct a SIDACtor® device
body meets UL 94V-0 requirements for flammability.
Figure 3.17 UL 497B Strike Voltage Breakdown Test
R1
50,000 Ω 25 W
Figure 3.18 UL 497B Discharge Test
Variable
R1
DC Supply * 5 MΩ
0-12,000 V
50 W
R2
10 Ω 5 W
C1
Variable DC Supply
0-1000 V
© 2011 Littelfuse, Inc.
Specifications are subject to change without notice.
Please refer to www.littelfuse.com for current information.
V
R2
10 Ω
5W
Spot
Switch
C1
Test
Specimen
*Or Voltage Capability Necessary to
Develop 10,000 V Across Capacitor
233
Revised: April 15, 2011
V
Test
Specimen