Surge Tolerant Fuses
Application Notes
Introduction
Interference by induction (Power Induction)
Telecommunication equipment acts as a source for data
exchange between subscribers. Communication takes place in
various ways, e. g. telephone, FAX etc.
Induction voltages occurring as interference on telecom
lines are usually a result of circulating or equalizing currents
in the earth or are produced by strong currents in adjacent
power cables.
SUBSCRIBER
EXCHANGE
EXCHANGE
SUBSCRIBER
SUBSCRIBER
EXCHANGE
Distances between individual subscribers (man, machine) can
vary significantly thereby subjecting network connections
(overhead lines, signal cables) to various interferences caused
by:
TEL.-LINE
●
●
●
Atmospheric interference, (lightning strike, switching
operations)
Interference by power induction (equalizing currents,
vicinity of power cables)
POWER LINE
Direct contact with energy network (short-circuits)
Direct contact with the power network (Power Contact)
Interference sources
Atmospheric interference (Lightning Strike)
SUBSCRIBER / EXCHANGE
LIGHTNING STRIKE
SUBSCRIBER
EXCHANGE
POWER CABLE
SHORT-CIRCUIT
Interference due to lightning strikes occurs frequently on
exposed overhead telephone lines. Voltages as a result of this
atmospheric discharge can be 100 kV with discharge currents
up to 150 kA.
Interference of unusually high intensity and long duration (a
few seconds to several minutes) on a telephone line occurs
when there is direct contact with a power network (e.g. short-
circuit with an adjacent power cable).
158
Schurter, Inc. ¥ Phone 707-778-6311 ¥ Fax 707-778-6401 ¥ E-mail: info@schurterinc.com ¥ Website http://www.schurterinc.com
ETC [ ETC ]
