Emerson Liebert Surge and Signal Protection - Manual (Page 2)

Typical Hybrid Advantage Surge Current Sharing Data
0 5,000 10,000 15,000 20,000 25,000 30,000
100.0
90.0
80.0
70.0
60.0
50.0
40.0
30.0
20.0
10.0
0.0
Hybrid SAD Module Interceptor MOV Module
Total Surge Current (Amperes)
P
e
rc
e
n
ta
ge o
f Sur
ge C
ur
re
n
t (%)
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.
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
disconnect phase, the nominal levels are
continually monitored until the system
voltage is stable, at which point the SAD
circuit is brought back on line.
Second, a regulated amount of high-
energy surge current is transitioned to
the secondary MOV suppression modules.
This is accomplished through an
impedance matching network utilizing a
series of controlled copper geometries in
conjunction with custom engineered
high-voltage/high-energy component
distribution. This ultimately limits the
amount of high-energy surge current
through the SAD module to an acceptable
level and diverting the remaining surge
current through the MOV module.
2
Multi-Stage System of Suppression
S•A•D Hybrid Technology