Emerson Liebert Surge and Signal Protection User Manual
Surge an
d Signal Protection
for Business-Critical Continuity
Liebert Hybrid Advantage
Total Protection For Your High Availability Systems
Multi-Stage System of Suppression
S•A•D Hybrid Technology
The Liebert Hybrid Advantage is the first hybrid product in the industry to offer a
true, coordinated multi-stage system of suppression. It integrates the fast response
time of the Silicone Avalanche Diode (SAD) with the high-energy capability of
the standard Liebert Interceptor MOV (Metal Oxide Varistor). Its patent-pending
Surge Current Transition Circuit continually monitors the operating level of the
SAD-switching to the secondary network of MOVs long before component failure
becomes a concern.
Other "hybrid" products fall into one of
two categories:
Self-sacrificing: This system significantly degrades or
fails with nominal fluctuations or high-energy events.
This design is extremely inconvenient to the customer,
and more importantly, it leaves an opportunity for
critical load upsets/failures.
Oversized components: Large components allow the
system to deal with nominal line voltage, as a result
clamping levels increase, defeating what it is designed
to do.
Typical Hybrid Advantage Surge Current Sharing Data
Hy
0 5,000 10,000 15,000 20,000 25,000 30,000
Total Surge Current (Amperes)
Percentage of Surge Current (%)
100.0
90.0
80.0
70.0
60.0
50.0
40.0
30.0
20.0
10.0
0.0
e
odul
AD M
d S
i
br
rc
e
t
In
tor MOV Module
p
e
The Liebert Answer:
The transitional method
Our answer lies in a two-part design
that actively disconnects the nominally
close components during a sustained
overvoltage and transitions from a
sensitive SAD circuit to a hardier MOV
array when subjected to damaging
transient levels.
First, a solid state comparator network
actively switches the SAD components out
of the transient control circuit when
exposed to line voltages in excess of their
Maximum Continuous Operating Voltage
(MCOV). While SAD components are
removed from the system, an appropriately
sized transient control network is available
for continued protection. During this
t phase, the nominal levels are
onnec
c
is
d
continually monitored until the system
voltage is stable, at which point the SAD
ght back on line
u
o
uit is br
irc
c
Second, a regulated amount of high-
nergy surge current is transitioned to
e
ondary MOV suppression modules.
ec
the s
This is accomplished through an
tching network utilizing a
a
e m
anc
ped
im
series of controlled copper geometries in
conjunction with custom engineered
nergy component
-e
gh
ge/hi
a
olt
-v
gh
hi
distribution. This ultimately limits the
amount of high-energy surge current
through the SAD module to an acceptable
evel and diverting the remaining surge
l
current through the MOV module.
.
2
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