Siemens GM-SG

Accessories
Table
8
.
Type
3
EF
Surge
Limiter
Application
Re
com
men
clatio
n
s
Type
3
EF
Surge
Limiters
The
type
3
EF
Surge
Limiter
may
be used
with
vacuum
circuit
breakers and
contactors
to
prevent
the
development
of
excessive
overvoltages
due
to
multiple
reignitions
or
virtual
current
chopping
.
This
is
primarily
of
concern
during
the
starting
of
motors
and the
switching
of
reactive loads
.
Surge
limiters
are
recommended
in
the
applications
shown
in
Table
8
.
If
surge
limiters
are
provided
,
and
an
overvoltage
does
occur
,
the
magnitude
of
the
voltage
will
be
limited
to
the
values indicated
in
Table
9
.
Recommended service
voltages
for
each
limiter
are
also shown
in
this table
.
Surge
limiters
are
intended
to
be
used
in
cable
network
systems
to
protect
motors
,
transformers
,
and
reactors
from
the
effects of
voltage
surges
associated
with
vacuum
circuit breaker
operations
.
If
lightning
or
switching
surges may
be
present
,
the
equipment
must
be
properly
protected
by
means
of
surge
arresters
.
The
surge
limiters
must
be disconnected
from
the
equipment
before
any
high
potential
testing
is
performed
.
The
one
-
minute
test
period
for
the
application
of
these
test
voltages
to
switchgear
may
damage
the
surge
limiters
.
Surge
Limiters
Recommended
Protected
(
Load
Equipment
)
Liquid
Transformers
No
Yes
1
Standard
BIL
Dry Type
Trans
.
5
kV
60
kV
BIL
No
7
kV
or
15
kV
95
kV
BIL
No
Yes
2
Locked
Rotor
Current
<
600
A
Motors
Locked
Rotor
Current
>
600
A
No
Reactors
Yes
Capacitors
No
7
Suige
limiter
not
necessary
if
surge
capacitors
or
surge
arresters
are
located
at
transformer
terminals
.
2
Surge
limiter
not
necessary
if
surge
capacitors
or
surge
arresters
are
located
at
machine terminals
.
Table
9
.
Type
3
EF
Surge
Limiter
Data
Rated
Voltage
MCOV
of
ZnO
element
kV
2.6
3.6
9.0
11.0
5.4
Series
Gap
Sparkover
Voltage
1.2
x
50
wave
kV
8 10
25
31
15
0.5
kA
Switching
Surge
Discharge Voltage
8
x
20
wave
kV
8
10 25
31
15
1.5
kA
Switching
Surge
Discharge
Voltage
8
x
20
wave
kV
8.3
12.4
28.9
33.0
16.5
12.0
Grounded
Wye
System
Applications
2.4
6.9
12.47
kV
8.32
4.16
7.2
13.2
13.8
12.0
6.9
Delta
System
Applications
4.16 4.8
12.47
kV
2.4 7.2
4.8 6.9
13.2
8.32
13.8
12.0
6.9
High
Resistance
Grounded
Wye
System
Applications
12.47
kV
2.4
4.16 6.9
7.2
13.2
8.32
13.8
51
Courtesy of NationalSwitchgear.com