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Product
Offer
 The STM40 is recommended
for a high risk level
 The STD10 is recommended
for a moderately high risk level and secondary protection of
loads (cascaded with incoming 40kA and 65kA surge arrestors)
Data
-
frequency: 50…60 Hz
-
Uc:
275 V
-
operating indication via mechanical indicator:
-
disconnection of short-circuited surge
arrestor to be conducted using a circuit-breaker
-
permissible internal short-circuit current
STD: 10 kA
-
permissible internal short-circuit current
STM:
-
1P+N, 3P and
3P+N: 25 kA
-
1P: 10 kA
The PRD65r surge arrestor is recommended
for a very high risk level (highly exposed site).
The PRD40r surge arrestor for a high
risk level.
Data
-
frequency: 50…60 Hz
-
Ic
full operating current:
-
1P and 3P: < 800 mA
-
1P+N and 3P+N: 0 mA
-
internal short-circuit current:
-
1P+N, 3P and 3P+N: 25 kA
-
1P (230 V): 10 kA
-
1P (400): 3 kA
-
operating indication via mechanical indicator:
-
end
of life indication:
-
normally closed contact:
-
DC: 12 V, ³10 mA
-
AC: 250 V, £1 A
Due to its multiple effects, lightning can lead to disturbances in
equipment and production means in industrial installations.
Their breakdown can lead to serious risks for the personnel
and their surroundings.
Lightning can notably
produce voltage surges that, just like industrial voltage surges
(switching, resonance, etc.) constitute harsh conditions for
installations and in particular electrical equipment (energy,
electronic, computer, remote information, etc.).
The effects of lightning
Lightning, as an
electric phenomenon, produces the same consequences as any other
electric current through a good or bad conductor.
Thermal effects
They are linked to the Joule
effect in bad conductors (wood, concrete, etc.): bursting due
to the vaporisation of water, melting of conductors with a small
cross-section or thin metal sheets.
A rise in the
voltage of earth connections
Lightning current has very steep rise fronts, impedances of the connection
circuit to the earth connector and of the earth connector itself
become dominant. Rise
in voltages result in arcings with neighbouring metal objects
that are not directly linked to this circuit (thus the risk
of fire), or the
destruction of electrical or electronic equipment that is incorrectly
connected to the earth.
Induced effects
Induced currents may appear
in conductors that are parallel to those that run off the lightning
current. These currents will themselves generate rises in voltage
that lead to the same type of inconveniencies as those described
above.
Electrodynamic
effects
The magnitude of induced currents in different circuits may generate
attraction or repulsion forces that could lead to deformations
or breaks.
Which buildings are
at risk?
A building is considered as
being exposed to lightning when it presents the following criteria:
Geographic criteria:
-
building isolated in a rural zone
-
building surrounded by tall trees
-
building located in a humid or swampy zone
-
building located on a peak, on a relief or a prominence.
Criteria linked
to infrastructures:
-
building supplied by overhead electrical
networks
-
building supplied by overhead communication
networks
-
building fitted out with a lightning conductor or near a lightning
conductor.
However. .
.
-
lightning conductors protect buildings
against the direct effects of lightning
-
lightning conductors do not protect electrical
and electronic devices against the indirect effects of lightning:
-
induced or conducted voltage
surges
-
rises in earth voltage.
Choosing the right
type of protection
Today, there are ways
to protect the electric installations in Buildings, the production
and transportation of Energy, the equipment in Infrastructures
and Industrial sites against the direct or indirect effects
of lightning. The need to even better satisfy customer expectations
and the recent evolution of standards, has led Schneider Electric
to develop a new range of surge arrestors. This modular offer
is suitably designed for the protection needs in the residential,
commercial and industrial sectors. It is in compliance with
the international IEC 61 643-1 class 2 test standard.
Risk evaluation of each installation is essential for the effective
protection of electric equipment as well as to ensure the best
posssible continuity of supply. For this, just choose a surge
arrestor in function of the criteria linked to both the loads
to be protected as well as the site's characteristics.
Low Voltage modular surge arrestors can be installed in electric
enclosures, switchboards or cabinets.
They are intended for the protection of single-phase or three-phase
electrical installations against transient atmospheric
voltage surges.
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