GE IFCV51AD User manual

GEK
-
49946
E
INSTRUCTIONS
TIME
OVERCURRENT
RELAYS
WITH
VOLTAGE
RESTRAINT
TYPES
IFCV
51
AD
IFCV
51
BD
.. .
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GE
Protection
and
Control
205
Great
Valley
Parkway
Malvern
,
PA
19355
-
1337
Courtesy of NationalSwitchgear.com

GEK
-
49946
CONTENTS
PAGE
DESCRIPTION
APPLICATION
CALCULATION
OF
SETTINGS
CONSTRUCTION
RATINGS
3
3
4
5
6
6
INDUCTION
UNIT
HIGH
-
SEISMIC
INSTANTANEOUS
UNIT
HIGH
-
SEISMIC
TARGET
AND
SEAL
-
IN
UNIT
7
7
CONTACTS
BURDENS
.
8
8
8
INDUCTION
UNIT
HIGH
-
SEISMIC
INSTANTANEOUS
UNIT
CHARACTERISTICS
INDUCTION
UNIT
HIGH
-
SEISMIC
INSTANTANEOUS
UNIT
HIGH
-
SEISMIC
TARGET
AND
SEAL
-
IN
UNIT
RECEIVING
,
HANDLING
AND
STORAGE
ACCEPTANCE
TESTS
VISUAL
INSPECTION
MECHANICAL
INSPECTION
DRAWOUT
RELAY
TESTING
POWER
REQUIREMENTS
,
GENERAL
INDUCTION
UNIT
HIGH
-
SEISMIC
INSTANTANEOUS
UNIT
HIGH
-
SEISMIC
TARGET
AND
SEAL
-
IN
UNIT
INSTALLATION
INSTALLATION
TESTS
PERIODIC
CHECKS
AND
ROUTINE
MAINTENANCE
..
INDUCTION
UNIT
HIGH
-
SEISMIC
INSTANTANEOUS
UNIT
HIGH
-
SEISMIC
TARGET
AND
SEAL
-
IN
UNIT
CONTACT
CLEANING
SYSTEM
TEST
8
9
9
9
9
10
10
10
10
11
11
11
12
13
14
14
14
15
15
15
15
15
16
SERVICING
16
INDUCTION
UNIT
HIGH
-
SEISMIC
INSTANTANEOUS
UNIT
HIGH
-
SEISMIC
TARGET
AND
SEAL
-
IN
UNIT
RENEWAL
PARTS
LIST
OF
FIGURES
18
18
18
19
-
2
-
Courtesy of NationalSwitchgear.com

GEK
-
49946
TIME
OVERCURRENT
RELAYS
WITH
VOLTAGE
RESTRAINT
TYPES
IFCV
51
AD
IFCV
51
BD
DESCRIPTION
The
Type
IFCV
51
AD
relay
is
a
single
-
phase
,
extended
range
,
very
inverse
time
overcurrent
relay
with
voltage
restraint
,
similar
to
the
IFC
51
A
relay
except
that
a
voltage
restraint
U
-
magnet
and
coil
has
been
added
that
produces
a
restraint
torque
that
opposes
the
operating
coi
1
.
The
time
overcurrent
unit
is
The
IFCV
51
B
0
is
overcurrent
is
included
,
respectively
,
of
the
IFCV
51
BD
,
with
components
identified
by
the
nomenclature
used
throughout
the
text
.
The
relays
are
equipped
with
a
dual
-
rated
target
and
seal
-
in
unit
having
two
electrically
separate
contacts
.
They
are
mounted
in
a
size
Cl
case
of
molded
construction
.
The
outline
and
panel
drilling
dimensions
are
shown
in
Figure
18
for
semi
-
flush
mounting
,
and
in
Figure
19
for
surface
mounting
.
When
semi
-
flush
capa
bi
1
i
ty
.
similar
to
the
IFCV
51
AD
except
that
an
instantaneous
Figures
1
and
2
show
the
front
and
back
views
,
mounted
on
a
suitable
panel
,
these
relays
have
a
high
seismic
The
internal
connections
are
shown
in
Figure
3
for
the
IFCV
51
AD
,
and
in
Figure
4
for
the
IFCV
51
BD
.
APPLICATION
A
system
must
be
protected
against
prolonged
generator
contribution
to
a
fault
on
the
system
.
contributing
current
,
the
generator
.
The
IFCV
relay
is
one
of
several
relays
designed
specifically
for
this
application
,
or
applied
to
provide
such
back
-
up
protection
.
Others
are
the
Type
IFCS
voltage
-
controlled
overcurrent
relay
,
or
three
single
-
phase
distance
relays
plus
a
timer
(
for
balanced
fault
back
-
up
protection
)
,
and
the
Type
INC
or
SGC
relays
for
unbalanced
fault
back
-
up
protection
.
Such
back
-
up
protection
is
best
made
at
the
source
of
the
The
choice
between
the
IFCV
or
the
distance
relays
is
determined
primarily
by
the
protective
relaying
,
with
which
the
generator
back
-
up
relays
must
be
selective
.
For
example
,
if
the
lines
leaving
the
station
bus
are
protected
by
very
inverse
time
overcurrent
relays
,
then
Type
IFCV
relays
should
be
used
.
These
instructions
do
not
purport
to
cover
ell
details
or
variations
in
equipment
nor
to
provide
for
every
possible
contingency
to
be
met
in
connection
with
instailation
,
further
information
be
desired
or
should
particular
problems
arise
which
are
not
covered
sufficiently
for
the
purchaser
'
s
purposes
,
the
matter
should
be
referred
to
the
General
Electric
Company
.
To
the
extent
required
the
products
described
herein
meet
applicable
ANSI
,
but
no
such
assurance
is
given
with
respect
to
local
codes
and
ordinances
because
they
vary
greatly
.
Should
operation
or
maintenance
.
IEEE
and
NEKA
standards
/
-
3
-
Courtesy of NationalSwitchgear.com

6
EK
-
49946
This
would
be
typical
of
installations
where
the
generator
connects
to
the
bus
at
generator
voltage
,
installations
generally
connect
to
a
high
voltage
system
,
on
which
distance
or
pilot
relaying
schemes
are
frequently
used
for
the
line
protection
.
In
such
cases
,
distance
relays
such
as
the
CEB
13
C
,
plus
a
timer
,
would
be
the
usual
choice
for
system
back
-
up
to
provide
coordination
with
the
line
relaying
.
On
the
other
hand
,
unit
generator
-
transformer
For the situations
noted above
,
the
recommended
practice
is
to
use
three
IFCV
relays
,
one
per
phase
,
or
three
single
-
phase
distance units
plus
a
timer
.
In
many
cases
,
especially
on
larger
machines
,
a
negative
sequence
time
overcurrent
relay
,
Type
INC
or
SGC
,
is
installed
to
provide
back
-
up
protection
against
unbalanced
system
faults
.
In
such
cases a
single
Type
IFCV
relay
,
to
protect
against
balanced
system
faults
,
could
be
considered
as
a
minimum
requirement
.
In
some
applications
it
may
be
more
advantageous
to
use
a
voltage
-
controlled
Type
IFCS
relay
rather
than
an
IFCV
.
The
IFCV
can
provide
faster
back
-
up
protection
than the
IFCS
,
particularly
in
instances where the
generator
voltage
does
not
drop
significantly
below
rated
voltage
during
fault
conditions
.
On
the
other hand
,
if
the
generator
voltage
always
drops
below
the
setting
of
the
undervoltage
unit
in
the
IFCS
for
all
faults
for
which the
generator
back
-
up
is
required
to
operate
,
better
sensitivity
can
be
obtained
by
using
the
IFCS
rather than
the
IFCV
.
The
current
source
for
Type
IFCV
relays
should
be
current
transformers
at
the
neutral
end
of
the
generator
windings
when
such
CT
'
s are
available
.
With
these
connections
,
in
addition
to
external
-
fault
back
-
up
protection
the
relays
will
provide
generator
fault
back
-
up
protection
even
if
the
generator
breaker
is
open
or
there
are
no
other
sources
of
generation
on
the
system
.
If
the
neutral
CT
'
s
are
not
available
,
then
it
will
be
necessary
to
use
line
-
side
CT
'
s
.
With
these
connections
,
Type
IFCV
relays
will
be
operative
as
fault
back
-
up
protection
for
the
generator
only
when the
generator
breaker is
closed
,
and
there
is
another
source
of
generation
on
the
system
.
Phase
-
to
-
phase
voltage
should
be obtained
from
the
generator
potential
transformers
.
Loss
of
potential
to
the
Type
IFCV
relay
will
cause
the
relay
to
trip
if
the
generator
load
current
,
expressed
in
relay
secondary
amperes
,
is
greater
than
the
pickup
current
of
the
relay
.
An
additional
relay
,
the
Type
CFVB
,
is available
for
protection
against
false
tripping
due
to
this
accidental
loss
of
the
relay
restraint
voltage
.
The
diagram
in
Figure
5
shows
typical
external
connections
for
the
Type
IFCV
relays
when the
generator
connects to
the
bus
at
generator
voltage
.
If
Type
IFCV
relays
are
applied
on
a
unit
generator
-
transformer
installation
,
the
external
connections
shown
in
Figure
6
are
typical
.
-
4
-
Courtesy of NationalSwitchgear.com

GEK
-
49946
CALCULATION
OF
SETTINGS
Pickup
with
full
voltage
restraint
of
the
Type
IFCV
relay
should
generally
be
set
between
200
%
and
250
%
of
full
load
current
on
regulated
generators
,
and
between
150
%
and
200
%
full
load
current
on
unregulated
generators
.
The
relay
time
setting
is
determined
by
system
selectivity
requirements
.
Though
the
current
decrement
curves
of
the
generator
must
be
taken
into
consideration
to
determine
the
actual
operating
time
of
the
Type
IFCV
relay
,
simplifying
assumptions
can
be
made
which
facilitate
application
of
the
Type
IFCV
relay
and
yet
maintain
a
satisfactory
operating
performance
.
The
maximum
fault
current
condition
for
which
time
-
current
coordination
must
be
obtained
should
be
based
on
the
transient
reactance
of
the
generator
.
If
the
calculations
are
further
based
on
the
premise
that
for
a
bus
fault
the
voltage
presented
to
the
Type
IFCV
relay
is
0
,
then
the
Type
IFCV
can
be
coordinated
with
the
bus
and
/
or
system
relaying
on
a
straight
overcurrent
basis
.
Coordination
of
the
Type
IFCV
relay
and
other
system
relays
for
system
faults
where
voltage
will
be
presented
to
the
Type
IFCV
relay
is
thereby
assured
.
This
conservative
assumption
of
the
zero
-
voltage
fault
is
equally
applicable
to
the
unit
generator
-
transformer
case
,
even
though
the
IFCV
restraint
voltage
may
come
from
generator
potential
transformers
,
justification
for
this
application
assumption
is
its
inherent
conservatism
,
and
the
basic
fact
that
the
operating
characteristic
of
the
Type
IFCV
relay
is
fairly
constant
for
all
low
-
voltage
conditions
.
The
CONSTRUCTION
The
IFCV
induction
disk
relays
consist
of
a
molded
case
,
cover
,
support
structure
assembly
,
and
a
connection
plug
to
make
up
the
electrical
connection
.
See
cover
figure
and
Figures
1
and
2
.
Figures
1
and
2
show
the
induction
unit
mounted
to
the
molded
support
structure
.
This
disk
is
activated
by
a
current
-
operated
coil
mounted
on
a
laminated
U
-
magnet
and
restrained
by
a
voltage
-
operated
coil
mounted
on
a
laminated
U
-
magnet
.
The
disk
and
shaft
assembly
carries
a
moving
contact
that
completes
the
alarm
or
trip
circuit
when
it
touches
a
stationary
contact
.
The
disk
assembly
is
restrained
by
a
spiral
spring
to
give
proper
contact
closing
and
its
rotation
is
retarded
by
a
permanent
magnet
mounted
in
a
molded
housing
on
the
support
structure
.
The
drawout
connection
/
test
system
for
the
Cl
case
,
shown
in
Figure
17
,
has
provisions
for
14
connection
points
,
and
a
visible
CT
shorting
bar
located
up
front
.
As
the
connection
plug
is
withdrawn
,
it
clears
the
shorter
contact
fingers
in
the
output
contact
circuits
first
.
Thus
,
the
trip
circuit
is
opened
before
any
other
circuits
are
disconnected
.
The
CT
shorting
bar
is
engaged
by
the
current
circuit
fingers
(
located
at
the
lower
front
of
the
case
)
to
short
-
circuit
external
current
transformer
secondary
connections
.
The
window
provides
visual
confirmation
of
CT
shorting
.
The
connection
plug
then
clears
the
voltage
circuit
and
current
circuit
fingers
on
the
case
,
and
finally
those
on
the
relay
support
structure
,
to
completely
de
-
energize
the
drawout
element
.
-
5
-
Courtesy of NationalSwitchgear.com

GEK
-
49946
There
is
a
High
-
Seismic
target
and seal
-
in
unit mounted
to
the
front
left
of
the
support
structure
,
contacts
,
one
of
which
is
in
series
with
its
coil
and
in
parallel
with
the
contacts
of
the
induction
unit such that when the induction
unit
contacts
close
,
the seal
-
in
unit
picks
up
and
seals
in
.
When the
seal
-
in
unit
picks
up
,
it
raises
a
target
into view which
latches
up
and
remains
exposed
until
released
by
presing
a
button located
on
the
upper
left
side
of
the
cover
.
The
seal
-
in
unit
has
two
electrically
-
separate
The
IFCV
51
BD
model
relays
,
in
addition
to
the
above
,
contain
a
High
Seismic
instantaneous
unit
(
see
Figure
1
)
.
electrically
separate
contacts
and is
mounted
to
the
front
right
of
the
support
structure
.
When the
instantaneous
unit
picks
up
it
raises
a
target
,
which latches
up
and
remains
exposed
until
it
is
released
.
The
same
reset
button that releases
the
target
seal
-
in
unit
also
releases the
target
of
the
instantaneous
unit
.
The
instantaneous
unit
has
two
Magnetic
shields
,
depicted
in
Figure
1
,
are
mounted
to
the
support
structure
to
eliminate
the
proximity
effect
of
external
magnetic
materials
.
Both
the
High
-
Seismic
target
and seal
-
in
unit
and
the
High
-
Seismic
instantaneous
unit have the
letters
"
Hi
-
G
"
molded
into their
target
blocks
to
distinguish
them
as
High
-
Seismic
units
.
Seismic
Fragility
Level
exceeds
peak
axial acceleration
rate
of
lOg
'
s
(
4
g
ZPA
)
when
tested
using
a
biaxial multi
-
frequency
input
motion
to
produce
a
Required
Response
Spectrum
(
RRS
)
in
accordance
with
the
IEEE
Guide for
Seismic
Testing
of
Relays
,
STD
501
-
1978
.
RATINGS
The
relays
are
designed
for
operation
in
an
ambient
air
temperature
from
-
20
OC
to
+
55
°
C
.
INDUCTION
UNIT
The
current
coil
ratings
are
given
in
Table
I
.
TABLE
I
-
2
-
16
AMPERE
TAP
RANGE
TAP
2
2.5
3
4
5
6 8
10
12
16
Continuous
Current
Rating
3.8
4.4
4.9
5.4
6.0 6.5
7.0
7.6
8.1 8.5
The
relay
will
pick
up
at
the
tap
value
when
rated
voltage
is
applied
to
the
restraint circuit
,
pick
up
at
25
%
trip
value
,
value
of
restraint
voltage
.
With
0
voltage
on
the
restraint
circuit
,
the
relay
will
Figure
7
shows the
pickup
current
required
for
any
The
voltage
restraint coil
is rated
continuously
for
the
nameplate
voltage
at
rated
frequency
.
-
6
-
Courtesy of NationalSwitchgear.com

GEK
-
49946
The
one
-
second
thermal
ratings
are
listed
i
#
Table
II
.
TABLE
II
One
-
Second
Rating
Any
Tap
(
Amperes
)
Time
Overcurrent
Unit
(
Amperes
)
Model
K
16
,
384
128
2
-
16
IJCV
51
HIGH
-
SEISMIC
INSTANTANEOUS
UNIT
The
instantaneous
coil
is
tapped
for
operation
on
either
one
of
two
ranges
(
H
or
L
)
.
Selection
of
the
high
or
low
range
is
determined
by
the
position
of
the
link
located
on
the
top
of
the
support
structure
.
See
Figure
1
and
Table
III
.
TABLE
III
Continuous
One
Second
Link
**
Range
Rating
Rating
Position
(
Amps
)
(
Amps
)
(
Amps
)
High
-
Seismic
Instantaneous
Unit
(
Amps
)
K
6
-
30
10.2
L
67
,
600
260
6
-
150
19.6
30
-
150
H
*
*
The
range
is
approximate
,
which
means
that
the
6
-
30
,
30
-
150
may
be
6
-
28
,
28
-
150
.
There
will
always
be
at
least
one
ampere
overlap
between
the
maximum
L
setting
and
the
minimum
H
setting
.
Whenever
possible
,
be
sure
to
select
the
higher
continuous
and
short
-
time
ratings
.
Higher
currents
may
be
applied
for
shorter
lengths
of
time
in
accordance
with
the
formula
:
I
+
v
/
K
/
T
is
in
series
with
the
time
overcurrent
unit
Since
the
instantaneous
unit
coil
coil
,
see
Tables
II
and
III
to
determine
the
current
-
limiting
element
for
both
continuous
and
short
-
time
ratings
.
HIGH
-
SEISMIC
TARGET
AND
SEAL
-
IN
UNIT
Ratings
for
the
target
and
seal
-
in
unit
are
shown
in
Table
IV
.
TABLE
IV
TAP
0.2
2.0
(
ohms
)
(
amperes
)
(
amperes
)
(
seconds
)
(
seconds
)
(
ohms
)
(
ohms
)
8.3
0.24
DC
Resistance
+
10
%
Minimum
Operating
Carry
Continuously
Carry
30
amps
for
Carry
10
amps
for
60
Hertz
impedance
50
Hertz
impedance
0.2
2.0
0.37
2.3
0.05
2.2
0.45
20
0.65
50
0.54
42
-
7
-
Courtesy of NationalSwitchgear.com

GEK
-
49946
If
the
tripping
currrent
exceeds
30
amperes
,
an
auxiliary
relay
should
be
used
,
the
connections
being
such
that
the
tripping
current
does
not
pass
through
the
contacts
or
the
target
and
seal
-
in
coils
of
the
protective
relay
.
CONTACTS
The
current
-
closing
rating
of
the
contacts
is
30
amperes
for
voltages
not
exceeding
250
volts
,
unit
.
The
current
-
carrying
rating
is
limited
by
the
ratings
of
the
seal
-
in
BURDENS
INDUCTION
UNIT
The
potential
burdens
at
rated
voltage
and
rated
frequency
are
given
in
Table
V
.
TABLE
V
Vol
t
Volts
Freq
.
Watts
Vars
Amps
120
50
9.26
14.4
17.1
17.3
19.7
120
60
9.43
The
current
circuit
burdens
with
5
amperes
flowing
in
the
lowest
tap
are
listed
in
The
burden
on
any
other
tap
with
5
amperes
flowing
is
approximately
(
Lowest
Tap
/
Actual
Tap
)
2
times
the
burden
for
the
lowest
tap
.
Table
VI
.
TABLE
VI
r
Impedance
Ohms
'
Range
Frequency
Tap
Amp
VA
PF
2
-
16
50
2.58
77.5
0.43
66.5
0.43
2
5
2
-
16
60
3.10
2
5
HIGH
-
SEISMIC
INSTANTANEOUS
UNIT
The
High
-
Seismic
instantaneous
unit
burdens
are
listed
in
Table
VII
.
TABLE
VII
Burdens
in
Ohms
(
Z
)
Times
Pickup
Burdens
at
Min
.
Pickup
(
Ohms
)
li
-
Seismic
,
Inst
.
Unit
Hz
Link
(
Amps
)
Min
.
Range
Pickup
Position
(
Amps
)
(
Amps
.
)
R
Jx
Z
3
10
20
L
6
-
30
6
0.110
0.078
0.135
0.095
0.081
0.079
6
-
150
60
30
-
150
30
H
0.022
0.005
0.023
0.022
0.022
0.022
L
6
-
30
6
0.092
0.065
0.112
0.079
0.068
0.066
6
-
150
50
H
30
-
150
30
0.018
0.004
0.019
0.018
0.018
0.018
-
8
-
Courtesy of NationalSwitchgear.com

GEK
-
49946
CHARACTERISTICS
INDUCTION
UNIT
TABLE
VIII
-
Tap
Connections
1.0
1.25 1.5 3.0 4.0
0.625
2.0
2.5
Zero
Volts
120
Volts
0.5 0.75
10.0 12.0
16.0
6.0
8.0
2.0
2.5 3.0 4.0 5.0
G
A
A
C
A
F
A A A
A
Taps
C
G
F F E H D H B
H
Pickup
Pickup
1
n
these
relays
1
s
defined
as
the
current
required
to
close the
contacts
from
the
0.5
time
-
dial
position
.
Current
settings
are
made
by
means
of
two
movable
leads
that
connect to
the
tap
block
at
the
top
of
the
support
structure
(
see
Figure
1
)
.
The
tap
block
1
s
marked
A
through
H
.
See
the
nameplate
on
the
relay
for
tap
settings
.
The
relay
will
pick
up
at
tap
value when rated
voltage
1
s
applied
to
the
restraint
circuit
.
With
0
voltage
on
the
restraint
circuit
,
the
relay
will
pick
up
at
25
%
tap
value
.
Figure
7
shows
typical
pickup
current
required
for
any
given
value
of
restraint
voltage
.
Pickup
1
s
affected
by
the
phase
angle
of
the
fault
current
.
A
typical
phase
angle
characteristic
1
s
shown
1
n
Figure
8
.
Operating
Time
Accuracy
The
IFCV
relays
should
operate
within
+
7
%
or
+
0.050
second
,
whichever
1
s
greater
.
Figures
9
and
10
show the
time
-
current
characteristics
for
IFCV
relays
.
The
setting
of
the
time dial determines
the
length
of
time
required
to
close the
contacts
for
a
given
current
.
The
higher
the
time
-
dial
setting
,
the
longer
the
operating
time
.
The
contacts
are
just
closed
when
the
time dial is
set to
0
.
setting
occurs
when the
time dial
1
s
set to
10
and the
disk
has
to
travel
Its
maximum distance
to
close the
contacts
.
The
maximum time
HIGH
-
SEISMIC
INSTANTANEOUS
UNIT
The
instantaneous unit
has
a
25
-
to
-
l
range
with
a
tapped
coil
,
low
ranges
,
selected
by
means
of
a
link
located
on
the
top
of
the
support
structure
.
See
Figure
1
.
Figure
12
.
HIGH
-
SEISMIC TARGET
AND
SEAL
-
IN
UNIT
There
are
high
and
The time
-
current
curve
for
the
instantaneous unit
1
s
shown
in
The
target
and seal
-
in
unit
has
two
tap
selections
located
on
the
front
of
the
unit
.
See
Figure
1
.
-
9
-
Courtesy of NationalSwitchgear.com

GEK
-
49946
RECEIVING
,
HANDLING
AND
STORAGE
These
relays
,
when
not
included
as
part
of
a
control
panel
will
be
shipped
in
cartons
designed
to
protect
them
against
damage
,
relay
,
examine
it
for
any
damage
sustained
in
transit
.
resulting
from
rough
handling
is
evident
,
file
a
damage
claim
at
once
with
the
transportation
company
and
promptly
notify
the
nearest
General
Electric
Sales
Office
.
Immediately
upon
receipt
of
a
If
injury
or
damage
Reasonable
care
should
be exercised
in
unpacking
the
relay
in
order that
none
of
the
parts
are
injured
or
the
adjustments
disturbed
.
If
the
relays
are
not to
be
installed
immediately
,
they
should
be
stored
in
their
original
cartons
in
a
place
that
is
free from
moisture
,
dust
and
metallic
chips
.
Foreign
matter
collected
on
the
outside
of
the
case
may
find
its
way
inside
when the
cover
is
removed
,
and
cause
trouble
in
the
operation
of
the
relay
.
ACCEPTANCE
TESTS
Immediately
upon
recept
of
the
relay
an
Inspection
and
Acceptance
Test
should
be
made
to
insure
that
no
damage
has been
sustained
in
shipment
and
that
the
relay
calibrations
have
not
been
disturbed
,
readjustment
is
necessary
,
refer
to
the
section
on
SERVICING
.
Since
operating
companies
use
different
procedures
for
Acceptance
and
Installation
Tests
,
the
following
section
includes
all
applicable
tests
that
may
be
performed
on
these
relays
.
These
tests
may
be
performed
as
part
of
the
Installation
or
ofv
the
Acceptance
Tests
,
at
the discretion
of
the
user
.
If
the
examination
or
test
indicates
that
VISUAL
INSPECTION
Check
the
nameplate
to
insure that
the
model
number
and
rating
of
the
relay
agree
with
the
requisition
.
Remove the
relay
from
its
case
and
check
that there
are
no
broken
or
cracked
parts
or
any
other
signs
of
physical
damage
.
MECHANICAL
INSPECTION
1
.
There
should
be
no
noticeable
friction
when the
disk is
rotated
slowly
clockwise
.
The
disk
should
return
by
itself
to
its
rest
position
.
Make
sure
the
control
spring
is
not
deformed
,
nor
its
convolutions
tangled
or
touching
each
other
.
2
.
3
.
The
armature
and
contacts
of
the seal
-
in
unit
,
as
well
as
the
armature
and
contacts
of
the
instantaneous
unit
,
should
move
freely
when
operated
by
hand
;
there
should
be
at
least
1
/
64
inch
wipe
on
the
seal
-
in
and
the instantaneous
contacts
.
-
10
-
Courtesy of NationalSwitchgear.com