GE IRT51E User manual

GEK
-
86038
C
INSTRUCTIONS
TEMPERATURE
RELAY
TYPES
:
IRT
51
E
IRT
51
F
IRT
51
G
IRT
51
H
GENERAL
ELECTRIC
Courtesy of NationalSwitchgear.com

GEK
-
86038
CONTENTS
PAGE
DESCRIPTION
3
INTRODUCTION
3
APPLICATION
4
RATINGS
6
BURDENS
8
CONSTRUCTION
9
RECEIVING
,
HANDLING
AND
STORAGE
10
INSTALLATION
PROCEDURE
10
OPERATING
UNIT
VOLTAGE
CONNECTIONS
AUXILIARY
CIRCUIT
CONNECTIONS
.
.
..
RTD
CONNECTIONS
11
11
13
INSPECTION
,
ACCEPTANCE
TESTS
,
PERIODIC
CHECKS
AND
ROUTINE MAINTENANCE
14
14
VISUAL
INSPECTION
MECHANICAL
INSPECTION
AND
ADJUSTMENTS
CONTACT INSPECTION
AND
CLEANING
AUXILIARY
BRUSHES
RHEOSTAT
CLEANING
ELECTRICAL
TESTS
15
16
16
16
16
CALIBRATION
PROCEDURE
18
20
RENEWAL
PARTS
21
LIST
OF
TABLES
2 2
LIST
OF
ILLUSTRATIONS
2
Courtesy of NationalSwitchgear.com

GEK
-
86038
TEMPERATURE
RELAY
TYPES
:
IRT
51
E
IRT
51
F
IRT
51
G
IRT
51
H
DESCRIPTION
INTRODUCTION
The
type
IRT
temperature
sensing
relays
are
designed
for
use
with
single
element
,
three
lead
,
resistance
temperature
detectors
(
RTD
)
.
Models
are
available
for
use
with
the
following
specific
type
RTD
:
a
.
10
ohm
at
25
°
C
copper
RTD
b
.
100
ohm
at
0
°
C
platinum
RTD
c
.
120
ohm
at
0
°
C
nickel
RTD
The
models
are
listed
in
Table
1
.
The
type
IRT
relays
will
provide
overtemperature
protection
,
either
trip
or
alarm
,
for
any
apparatus
that
is
equipped
with
one
of
the
listed
RTDs
.
continuously
adjustable
over
a
temperature
sensing
range
of
80
°
C
to
165
°
C
.
The
relays
are
These
relays
are
of
the
wattmetric
induction
disk
type
and
provide
various
contact
combinations
as
described
below
.
The
measuring
circuit
is
similar
to
a
Wheatstone
Bridge
,
except
that
two
adjacent
legs
of
the
bridge
are
replaced
by
transformer
secondary
windings
.
The
primary
winding
of
this
transformer
forms
the
polarizing
coil
of
the
wattmetric
unit
.
The
type
IRT
51
E
relay
is
an
overtemperature
sensing
relay
having
a
single
normally
-
open
contact
,
with
a
target
seal
-
in
unit
,
as
shown
in
Figure
7
.
The
relay
is
furnished
in
a
single
end
,
small
size
drawout
case
.
The
IRT
51
F
relay
is
an
overtemperature
sensing
relay
having
both
normally
-
open
and
normally
-
closed
output
contacts
.
These
contacts
are
provided
by
an
auxiliary
unit
(
A
)
operating
from
the
main
induction
disk
unit
contacts
in
a
pickup
,
seal
-
in
knock
down
circuit
,
as
shown
in
Figure
8
.
The
relay
is
self
-
resetting
when
the detected
temperature
falls
below
a
preselected
level
.
This
reset
temperature
is
continuously
adjustable
over
a
range
from
5
°
C
to
30
°
C
below
the
set
operating
temperature
.
A
manual
reset
target
is
included
,
which
is
operated
by
a
contact
of
the
auxiliary
unit
A
.
The
relay
is
mounted
in
a
single
end
,
small
size
drawout
case
.
The
type
IRT
51
G
is
an
overtemperature
sensing
relay
providing
two
normally
-
open
and
two
normally
-
closed
electrically
separate
output
contacts
,
provided
by
a
two
-
position
latching
relay
whose
operating
coil
(
OP
)
and
reset
coil
(
RE
)
are
controlled
by
the
left
-
hand
(
IRT
|
_
)
and
right
-
hand
(
IRTR
)
contacts
,
respectively
,
of
These
contacts
are
These
instructions
do
not
purport
to
cover
all details
or
variations
in
equipment
nor
to
provide
for
every
possible
contingency
to
be
met
in
connection
with
installation
,
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
NEMA
standards
;
3
Courtesy of NationalSwitchgear.com

GEK
-
86038
the
main
induction disk unit
,
as
shown
in
Figure
9
.
The
relay
operates
to
close
the
normally
-
open
output
contacts
whenever
the
detected
temperature
exceeds the
set
value
.
These
output
contacts
can
be
reset
:
a
.
manually
b
.
electrically
c
.
self
-
reset
by
means
of
external
connections
but
only
after
the detected
temperature
has
fallen
below
the
reset
temperature
of
the
main
unit and its
right
-
hand
(
IRTR
)
contact
has
closed
.
The
reset
level
of
the
main
unit
is
continuously
adjustable
from
5
oc
to
30
oc
below
its
operating
temperature
level
.
The
IRT
51
G
relay
is
mounted
in
a
double end
,
small
size drawout
case
.
The
type
IRT
51
H
is similar
to
the
IRT
51
G
except
an
RTD
probe
assembly
is
furnished
as
a
part
of
the
relay
model
.
The
probe
is
a
three
wire
,
single
element
,
tip
sensitive
,
100
ohm
at
OOC
,
platinum
RTD
.
The
probe
comes
with
a
fluid
seal
installation
fitting
and also
a
brass
reducing
fitting
for
use
where
required
(
see
INSTALLATION
PROCEDURE
)
.
APPLICATION
The
type
IRT
51
relays
can
be used
to
protect
any
apparatus
equipped
with
one
of
the
resistance
temperature
detectors
listed
in
the
INTRODUCTION
section
.
The
types
IRT
51
E
and
IRT
51
F
relays
are
intended
primarily
for
the
protection
of
motors
or
generators
having
the
RTD
'
s
embedded
in
the
windings
.
The
usable
temperature
range
of
80
°
C
to
165
°
C
makes them
particularly
suitable
for
application
on
machines
with
class
A
,
B
or
F
insulation
,
transformers
against
overheating
with
associated
RTD
’
s
placed
in
strategic
locations
in
the
tank
.
These
relays
may
also be
applied
to
protect
power
Typical
external
connections
for
the
type
IRT
51
E
relay
are
shown
in
Figure
10
.
Typical
external
connections
for
the
type
IRT
51
F
relay
are
shown
in
Figure
11
.
The
types
IRT
51
G
and
IRT
51
H
relays
are
intended
primarily
for
bearing
temperature
protection
of
rotating
equipment
.
Typical
external
connections
for
these
relays
are
shown
in
Figure
12
.
The
functions
that
temperature
relays
perform
depend
upon
the
type
of
equipment
to
be
protected
,
its
importance
to
the
system
,
and
its
location
in
the
system
.
In
unattended
stations
,
for
example
,
the
IRT
51
E
or
IRT
51
F
relays operating
from
embedded
RTD
'
s
may
be used
to
reduce
or remove
load
automatically
.
The
type
IRT
51
F
with
its
normally
-
open
(
IRT
[
_
)
and
normally
-
closed
(
IRTR
)
contacts
could
also
be
employed
to
prevent
an
increase
in
load until
the
temperature
has
returned
to
an
acceptable
level
.
In
attended
stations
,
the
function
of
these
relays
is
generally
to
provide
a
warning
alarm
that
an
overtemperature
condition
exists
,
especially
in
the
case
of
major
units
and
essential
auxiliary
power
equipment
.
In
addition
to
sounding
an
alarm
,
the
relays
may
also
initiate
a
timing
device which
causes
a
delayed
automatic
corrective action
if
the
station
operator
has
not
responded
to
the
alarm
within
a
reasonable
time
.
These
relays
should
not
be
used
to
determine
machine
load
,
since
operating
temperature
is
not
necessarily
a
reliable
indication
of
maximum
permissible
load
.
Other
design
limitations
may
place
more
stringent
restrictions
on
machine
rating
.
Courtesy of NationalSwitchgear.com

GEK
-
86038
TABLE
1
RELAY
MODEL
DESCRIPTION
TABLE
C
<
C
C
c
CVJ
ro
LU
LU
LU
LL
LL
LL
UJ
<
c
c
LD
UD
LL
.
Uu
U
_
C
C
C
r
-
H
<
XJ
OO
CD
CD
CD
<
CD
C
\
J
ro
eg
O
cc
s
:
LU
=
c
pH
I
—
1
CQ
LD
LD
in
LD LD
LD
LD
LO
LO
LO
LO LO
LO
>
-
S
C
ZD
CC
cc
cc
cc cc
cc
cc
cc
cc
CC
CC
CC
cc
—
J
z
LU
eg
og
eg eg
c
\
j
eg
eg
eg
OJ
eg
eg eg
eg
cc
For
use
with
:
10
ohm
@
250
C
copper
RTD
100
ohm
@
0
OC
platinum
RTD
120
ohm
@
0
°
C
nickel
RTD
X
X
X
X
X
X
X
X
X
X
X
X
X
RTD
furnished
with
relay
X
Adjustable
overtemperature
range
80
°
C
-
160
°
XXX
XXX
XXX
X
X
X
X
Adjustable
reset
temperature
5
°
-
30
°
C
below
set
operating
temperature
X
XXX
X
X
X
X
XX
Operating
Circuit
120
/
240
VAC
,
50
/
60
Hz
X
XXX
XXX
XXX
Auxi
1
iary
Circuit
120
/
240
VAC
,
50
/
60
Hz
125
/
250
VDC
XXX
XXX
XX
X
X
X
X
X
X
Target
Target
Seal
-
in
0.2
/
2.0
amp
DC
XXX
XXX
XX
X
X
X
XX
Reset
Features
Manually
Electrically
(
remote
)
Self
XXX
XXX
X
X
X
X
X
XXX
XXX
X
X
X
X
Number
of
Contacts
Electrically
Separate
N
.
0
.
Electrically
Separate
N
.
C
.
Convertible
N
.
0
.
or
N
.
C
.
contact
1
1
1
111 111
11
1
2
2
22
2
2
2
2
1
1
1
Internal
Connections
Figure
7
8
8
9
9
Outline
and
Panel
Drilling
Figure
18
18
17 17
17
Operative
Circuit
110
/
220
VAC
50
/
60
Hz
XXX
Auxiliary
Circuit
110
/
220
VAC
40
/
60
Hz
110
/
220
VDC
XXX
5
Courtesy of NationalSwitchgear.com

GEK
-
86038
It
is
important
to
note
that
these
type
IRT
relays
detect actual
temperature
,
not
rise
above ambient
.
The
temperature
setting
should
be
made
on
the
basis
of
long
term
trends
in
ambient
temperature
.
RATINGS
The
operating
unit
of
the
type
IRT
relays
has
a
center
tapped
coil
that
permits
operation
at
either
120
or
240
volts
AC
*
.
For
240
volt
operation
,
the
two
operating
coils
must
be
connected
in
series
.
For
120
volt
operation
,
the
two
operating
coils
must
be
connected
in
parallel
.
See
Figures
10
,
11
and
12
for
the
AC
power
source
connections
.
The
IRT
51
E
and
IRT
51
F
models
have
an
internal
,
insulated standoff
post
for
making
the series connection
,
while the
IRT
51
G
and
IRT
51
H
models
bring
all
of
the
operating
coil
leads
to
separate
terminals external
to
the
relay
.
The
IRT
51
E
and
IRT
51
F
models
are
shipped
from
the
factory
connected
for
240
volt
operation
.
Some
models
of
the
IRT
51
F
(
-
)
A
relay
are
rated
at
110
/
220
VAC
or
DC
.
See
Table
I
.
The
type
IRT
relays
are
suitable
for
operation
on
50
hertz and
60
hertz
power
systems
.
The
type
IRT
relays
are
designed
for
use
with the
following
specific
type
resistance
temperature
detectors
:
10
ohms
at
25
°
C
copper
RTDs
100
ohms
at
0
°
C
planinum
RTDs
120
ohm
at
0
°
C
nickel
RTDs
a
.
b
.
c
.
Use
only
the
specific
RTD
for
which
the
particular
model
IRT
was
designed
.
The
IRT
51
E
,
IRT
51
G
and
IRT
51
H
relays
are
furnished
with
a
target
and seal
-
in
unit
having
taps
for
0.2
amps
DC
and
2.0
amps
DC
operation
,
different
ratings
based
on
tap
settings
.
Table
2
shows
the
TABLE
2
TARGET
SEAL
-
IN
UNIT
RATINGS
O
!
TAP
0.2
+
0
%
|
Minimum
DC
operating
current
0.2
2.0
-
25
°
/
(
ohms
)
(
amps
)
(
seconds
)
(
seconds
)
(
amps
)
DC
resistance
+
10
%
7.0
0.13
i
Tripping
duty
!
Carry
30
amps
Carry
10
amps
j
Carry
continuous
i
Contact
current
closing
rating
(
amps
)
5.0 30.0
0.03 4.0
0.25
30.0
0.3 3.0
30 30
(
volts
Max
.
)
250 250
The
tap
setting
used
on
the seal
-
in
units
is
determined
by
the
current
drawn
by
the
trip
circuit
.
The
0.2
amp
tap
is
for
use
with
trip
circuits
that
operate
on
6
Courtesy of NationalSwitchgear.com

GEK
-
86038
currents
ranging
from
0.2
to
2.0
amps
DC
at
the
minimum
control
voltage
.
If
this
tap
is
used
with
trip
coils
requiring
more
than
2.0
amps
,
there
is
a
possibility
that
the
7.0
ohms
resistance
of
the
target
seal
-
in
unit
will
reduce
the
current
to
such
a
low
value
that
the
breaker
will
not
be
tripped
.
The
2.0
amp
tap
should
be
used
with
trip
coils
that
take
2.0
amps
DC
or
more
at
the
minimum
control
voltage
.
The
tripping
current
should
not
exceed
30
amps
at
the
maximum
control
voltage
.
If
the
tripping
current
exceeds
30
amps
,
an
auxiliary
relay
should
be
used
so
the
tripping
current
does
not
pass
through
the
target
seal
-
in
unit
.
The
IRT
51
F
relay
is
furnished
with
a
target
unit
and
an
auxiliary
telephone
type
relay
.
The
auxiliary
circuit
may
be
used
with
120
or
240
volts
AC
,
50
or
60
hertz
,
or
with
125
or
250
volts
DC
*
.
A
voltage
level
selection
link
is
located
inside
of
the
relay
on
top
of
the
resistor
mounting
plate
,
and
is
marked
"
LOW
"
for
120
and
125
volts
,
and
"
HIGH
"
for
240
and
250
volts
.
This
link
must
be
in
the
position
corresponding
to
the
voltage
level
being
applied
.
The
IRT
51
F
relay
is
shipped
from
the
factory
with
the
link
in
the
"
HIGH
"
position
.
Some
models
of
the
IRT
51
F
(
-
)
A
relay
are
rated
at
110
/
220
VAC
or
DC
.
*
See
Table
I
.
The
target
shows
whenever
an
overtemperature
condition
is
first
sensed
,
must
be
manually
reset
.
The
target
is
not
a
seal
-
in
type
.
It
The
auxiliary
telephone
-
type
relay
contacts
will
close
and
carry
30
amps
DC
These
momentarily
for
tripping
duty
at
control
voltages
of
250
volts
DC
or
less
,
contacts
will
carry
one
amp
continuously
and
have
an
interrupting
rating
as
shown
in
Table
3
.
TABLE
3
AUXILIARY
TELEPHONE
-
TYPE
RELAY
INTERRUPTING
RATINGS
AMP
INDUCTIVE
AMP
NON
-
INDUCTIVE
110
0.80
2.1
Vol
ts
AC
(
50
/
60
hertz
)
120
0.75
2.0
220
0.55
1.1
240
0.50
1.0
Volts
DC
48
1.0
3.0
110
0.5
1.7
125
0.5
1.5
220
0.28
0.78
250
0.25
0.75
The
IRT
51
G
is
furnished
with
a
target
seal
-
in
unit
and
a
latching
-
type
auxiliary
telephone
relay
.
See
TARGET
SEAL
-
IN
UNIT
RATINGS
,
Table
2
;
and
AUXILIARY
TELEPHONE
TYPE
RELAY
INTERRUPTING
RATINGS
,
Table
3
.
The
auxiliary
circuit
will
operate
whenever
an
overtemperature
condition
is
The
relay
will
not
permit
the
auxiliary
circuit
to
reset
until
the
detected
temperature
decreases
to
below
a
preselected
temperature
level
,
and
the
right
-
hand
(
IRTR
)
contact
has
closed
.
sensed
.
7
Courtesy of NationalSwitchgear.com

GEK
-
86038
The
auxiliary
circuit
may
be
reset
manually
by
pushing
upward
on
the
reset
rod
located
on
the
bottom
left
side
of
the
cover
.
Or
it
may
be
reset
electrically
from
a
remote
location
by
connecting
a
control
switch
across
terminals
19
and
20
.
Or
the
relay
may
be
made
self
-
resetting
by
shorting
terminals
19
and
20
together
.
If
either
the
remote
electrical
or
self
-
resetting
functions
are
selected
,
and
the
relay
is
reset
,
the
target
will
remain
in
view
.
To
remove
the
target
indication
,
the
reset
rod
must
be
pushed
manually
.
The
IRT
51
H
is
similar
to
the
IRT
51
G
.
The
difference
between
these
two
models
is
that
the
IRT
51
H
is
furnished
with
a
three
wire
,
single
element
,
tip
sensitive
,
100
ohms
at
0
OC
,
platinum
RTD
assembly
.
The
RTD
assembly
comes
with
a
special
brass
reducing
fitting
that
will
permit
replacement
of
existing
General
Electric
temperature
relays
,
Type
TBB
,
having
sylphon
bulbs
and
capillaries
,
with
an
IRT
51
H
.
See
Figure
4
,
RTD
Assembly
.
BURDENS
Table
4
shows
the
burdens
for
the
operating
units
of
the
type
IRT
relays
based
upon
the
type
of
RTD
for
which
the
unit
is
designed
.
TABLE
4
OPERATING
UNIT
BURDENS
RTD
DESCRIPTION
OHMS
UC
MATERIAL
VOLTS
*
FREQUENCY
MILLIAMPS
VOLT
-
AMPS
WATTS
2.61
7.62
10
25
63.5
60
120
copper
2.60
31.7
7.61
240
60
2.71
8.77
73.1
120
50
2.71
8.76
36.5
240
50
2.67
7.80
piatinum
65.4
100
0
120
60
2.69
7.87
240
32.8
60
9.04
2.79
75.3
120
50
2.80
37.8
9.07
240
50
2.79
8.17
120
0
nickel
120
60
68.1
2.79
240
34.0
8.16
60
2.91
78.4
9.41
120
50
9.41
2.91
240
50
39.2
The
milliamperes
for
the
110
/
220
volt
operation
are
approximately
92
%
of
the
values
shown
in
approximately
84
%
of
the
values
shown
in
Table
4
.
The
volt
-
amperes
and
watts
are
reduced
to
Table
4
.
Tables
5
,
6
and
7
show
the
burden
data
for
the
auxiliary
circuits
of
the
IRT
relays
.
The
IRT
51
F
,
IRT
51
G
and
IRT
51
H
relays
do
not
have
a
single
burden
,
rather
the
burden
changes
as
the
relay
auxilary
circuit
changes
its
state
from
reset
to
picked
up
.
Tables
6
and
7
reflect
the
transitional
and
steady
state
burdens
of
the
auxiliary
circuits
.
8
Courtesy of NationalSwitchgear.com

GEK
-
86038
TABLE
5
BURDEN
FOR
IRT
51
E
TARGET
SEAL
-
IN
UNIT
TAP
OHMS
0.2
7.0
2.0
0.13
TABLE
6
BURDEN
FOR
IRT
51
F
AUXILIARY
CIRCUIT
STATE
PICKED
UP
NOT
PICKED
UP
(
OHMS
)
VOLTS
FREQUENCY
MOMENTARY
CONTINUOUS
110
50
/
60
50
/
50
50
/
60
50
/
60
780
ohms
850
ohms
3530
ohms
3850
ohms
750
ohms
850
ohms
3850
ohms
3850
ohms
infinite
infinite
infinite
infinite
infinite
infinite
infinite
infinite
2650
ohms
2900
ohms
5400
ohms
5900
ohms
2550
ohms
2900
ohms
5200
ohms
5900
ohms
120
220
240
110
DC
125
DC
220
DC
250
DC
TABLE
7
BURDEN
FOR
IRT
51
G
AND
IRT
51
GH
AUXILIARY
CIRCUIT
TARGET
SEAL
-
IN
UNIT
DURING
VOLTS
FREQ
.
TRANSITION
STEADY
-
STATE
TAP
OHMS
110
50
/
60
50
/
60
50
/
60
50
/
60
1830
ohms
infinite
ohms
2000
ohms
infinite
ohms
3700
ohms
infinite
ohms
4000
ohms
infinite
ohms
1760
ohms
infinite
ohms
2000
ohms
infinite
ohms
3520
ohms
infinite
ohms
4000
ohms
infinite
ohms
0.2
7.0
120
2.0
0.13
220
240
no
DC
125
DC
220
DC
250
DC
CONSTRUCTION
The
relay
case
is
suitable
for
either
surface
or
semi
-
flush
panel
mounting
.
Hardware
is
provided
with
the
relay
for
either
mounting
method
.
The
cover
attaches
to
the
case
with
four
cover
screws
which
have
provisions
for
a
sealing
wire
.
The
cover
also
has
the
reset
mechanism
for
target
reset
.
On
the
IRT
51
G
and
IRT
51
H
,
this
reset
mechanism
is
used
to
manually
reset
the
relay
.
Care
must
be
taken
when
removing
or
replacing
the
cover
on
the
case
because
of
the mechancial interaction
between
the
reset
mechanism
and
the
individual internal
components
of
the
relay
.
Forcing
the
cover
on
or
off
may
damage
the
reset
mechanism
system
.
9
Courtesy of NationalSwitchgear.com

GEK
-
86038
The
back
of
the
case
has
studs
mounted
in
an
outer
block
.
These
studs
are
used
for
making
the
external
wiring
connections
to
the
relay
case
.
A
removable
connection
plug
connects
the
outer
block
to
an
inner
block
which
is
connected
to
the
internal
wiring
of
the
relay
.
Both
the
outer
and
inner
blocks
have
spring
-
backed
contact
fingers
to
assure
good
electrical
contact
with
the
connection
plug
.
The
relay
mechanism
is
mounted
in
a
steel
framework
called
a
cradle
and
is
a
complete
unit
with
all
leads
being
terminated
at
the
inner
block
.
The
cradle
is
held
securely
in
the
case
with
a
latch
at
the
top
and
the
bottom
and
by
a
guide
pin
at
the
back
of
the
case
,
into
the
case
upside
down
,
connections
,
also
locks
the
latch
in
place
,
connection
plug
in
place
.
The
case
and
cradle
design
prevents
inserting
the
relay
The
connection
plug
,
besides
making
electrical
The
cover
,
in
turn
,
holds
the
To
draw
out
the
relay
unit
from
the
case
,
first
carefully
remove
the
cover
,
then
the
connection
plugs
.
Shorting
bars
are
built
into
the
relay
case
to
short
the
current
transformer
circuits
.
Release
the
latches
.
The
relay
unit
may
now
be
removed
from
the
case
by
pulling
on
the
cradle
.
To
replace
the
relay
unit
,
follow
the
reverse
order
.
Use
care
when
placing
the
cover
back
on
to
the
relay
case
to
avoid
damaging
the
reset
mechanism
.
RECEIVING
,
HANDLING
AND
STORAGE
These
relays
,
when
not
included
as
part
of
a
control
panel
,
are
shipped
in
cartons
designed
to
protect
them
against
damage
,
relay
,
examine
it
for
any
damage
sustained
in
transit
,
handling
is
evident
,
file
a
damage
claim
at
once
with
the
transportation
company
and
promptly
notify
the
nearest
General
Electric
Apparatus
Sales
Office
.
Exercise
care
when
handling
or
unpacking
the
relay
,
to
avoid
disturbing
adjustments
or
damaging
the
relay
.
Immediately
upon
receipt
of
a
If
damage
due
to
rough
Perform
an
inspection
and
an
acceptance
test
as
soon
as
the
relay
is
received
to
make
sure
that
no
damage
was
sustained
during
shipment
and
that
the
relay
calibrations
have
not
been
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
particles
.
Foreign
matter
collected
on
the
outside
of
the
case
may
find
its
way
to
the
inside
of
the
case
when
the
cover
is
removed
,
creating
the
possiblity
of
relay
misoperation
.
INSTALLATION
The
location
should
be
clean
and
dry
,
free
from
dust
and
vibration
,
and
well
lighted
to
facilitate
inspection
and
testing
.
The
relay
should
be
mounted
on
a
vertical
surface
,
drilling
drawings
are
shown
in
Figures
17
and
18
.
The
outline
and
panel
10
Courtesy of NationalSwitchgear.com

GEK
-
86038
The
RTD
assembly
furnished
as
part
of
the
IRT
51
H
relays
is
shown
in
Figure
4
.
The
RTD
probe
is
tip
sensitive
;
therefore
,
the
probe
tip
must
come
in
direct
contact
with
the
material
whose
temperature
is
to
be
sensed
.
The
temperature
probe
is
not
spring
loaded
;
therefore
,
its
primary
application
is
for
sensing
the
temperature
of
fluids
.
The
one
-
half
to
three
-
eighths
inch
brass
reducing
bushing
pipe
fitting
shown
in
the
RTD
assembly
(
Figure
4
)
is
furnished
as
part
of
the
RTD
assembly
.
It
is
not
necessary
to
use
this
fitting
when
applying
the
RTD
assembly
to
new
equipment
.
The
primary
reason
this
fitting
is
furnished
is
to
readily
adapt
the
RTD
assembly
to
applications
which
already
have
a
temperature
sensing
element
installed
,
fitting
will
adapt
the
RTD
assembly
to
take
the
place
of
the
sylphon
tube
,
bulb
and
packing
gland
of
the
General
Electric
Company
temperature
relay
type
TBB
.
This
OPERATING
UNIT
VOLTAGE
CONNECTIONS
The
IRT
51
relays
may
be
used
with
an
operating
voltage
of
110
/
120
volts
AC
or
220
/
240
volts
AC
at
frequencies
of
50
or
60
hertz
.
A
simple
change
in
the
wiring
scheme
to
the
operating
unit
is
required
to
operate
at
either
of
the
two
different
voltage
levels
.
When
the
relay
is
shipped
from
the
factory
,
it
is
set
for
220
/
240
VAC
operation
.
Refer
to
the
external
connections
diagrams
shown
in
Figures
10
,
11
and
12
for
the
connections
to
be
used
for
different
voltage
sources
.
See
Table
1
for
the
relay
voltage
ratings
.
120
volt
AC
Operation
:
Coil
H
1
-
H
2
must
be
placed
in
parallel
with
coil
H
3
-
H
4
.
To
make
the
parallel
connection
,
connect
lead
HI
to
lead
H
3
,
and
lead
H
2
to
lead
H
4
.
Polarity
is
important
.
240
volt
AC
Operation
:
Coil
H
1
-
H
2
must
be
placed
in
series
with
coil
H
3
-
H
4
.
To
make
this
connection
,
connect
lead
H
2
to
H
3
.
Polarity
is
important
.
The
IRT
51
E
and
IRT
51
F
models
have
an
internal
insulated
standoff
post
at
terminal
8
A
to
assist
in
making
the
series
connection
for
240
volt
AC
operation
.
The
IRT
51
G
and
IRT
51
H
models
have
the
coil
leads
brought
to
individual
terminals
;
therefore
,
the
terminal
connections
must
be
made
external
to
the
relay
.
AUXILIARY
CIRCUIT
CONNECTIONS
IRT
51
E
:
For
trip
circuits
operating
on
currents
ranging
from
0.2
to
2.0
amps
DC
at
the
minimum
control
voltage
,
set
the
target
and
seal
-
in
tap
screw
in
the
0.2
amp
tap
.
For
trip
circuits
operating
on
currents
ranging
from
2
to
30
amps
DC
at
the
minimum
control
voltage
,
place
the
tap
screw
in
the
2.0
amp
tap
.
The
tap
screw
is
the
screw
holding
the
right
stationary
contact
of
the
target
seal
-
in
unit
.
To
change
tap
settings
,
it
is
important
that
the
stationary
contact
A
tap
changing
procedure
that
will
prevent
the
positions
not
be
disturbed
,
stationary
contacts
from
getting
out
of
adjustment
is
as
follows
:
1
.
Remove
the
connection
plug
.
2
.
Remove
one
of
the
screws
in
the
left
stationary
contact
and
place
it
in
the
desired
tap
.
11
Courtesy of NationalSwitchgear.com

GEK
-
86038
Remove
the
screw
from
the
other
tap
and
place
it
in
the
left
stationary
contact
.
3
.
During
relay
operation
,
tap
screws
should
not
be
in
both
taps
at
the
same
time
.
If
they
are
,
pickup
will
occur
at
the
higher
tap
value
.
The
relays
are
shipped
with
the
tap
screw
in
the
2.0
amp
tap
.
IRT
51
F
:
The
auxiliary
circuit
for
the
I
RTS
1
F
may
be
used
with
120
or
240
volts
AC
,
50
or
60
hertz
;
or
with
125
or
250
volt
DC
*
.
The
only
adjustment
that
must
be
made
to
accomodate
these
different
power
supplies
is the
position
of
a
voltage
level
selection
link
which is
located
internally
to
the
relay
and
may
be
easily
seen
when
viewing
the
top
of
the
relay
unit when
the
relay
is
removed
from
its
case
.
The
voltage
level
selection
link
is
labeled
"
LOW
"
and
"
HIGH
.
"
The
"
LOW
"
position
is
to
be used
for
120
/
125
volts
*
.
The
"
HIGH
"
position
is
to
be used
for
240
/
250
volts
*
.
The
voltage
level
selection
link
position
can
be
changed
by
loosening
the
thumb
screws
and
repositioning
the
link in
the
desired
position
.
The
link
should
not
be
permitted
to
connect
the
"
LOW
"
and
"
HIGH
"
positions
together
.
If
this is done
,
the
auxiliary
circuit
will
be
disabled and
will
not
operate
.
The
IRT
51
F
relay
also
has
a
set
of
convertible
contacts
on
terminals
9
and
10
.
If
a
normally
-
closed
contact
is desired
,
connect
the
green
lead
to
terminal
9
.
If
a
normal
1
y
-
open
contact
is desired
,
the
green
lead
should
be
connected
to
terminal
10
.
There
is
a
shorting
bar
between
terminals
9
and
10
.
This
shorting
bar
is
used
to
protect
current
transformer
circuits
from
being
opened
whenever
the
relay
connection
plug
is
removed
.
This
shorting
bar
may
be
removed
if
it
is
not
used
.
Some
models
of
IRT
51
F
(
-
)
A
relays
are
rated
at
110
/
220
VAC
or
DC
.
See
Table
1
.
IRT
51
G
and
IRT
51
H
:
The
auxiliary
circuit
for
the
IRT
51
G
and
IRT
51
H
relays
is
the
most
versatile
of
all
of
the
IRT
auxiliary
circuits
.
It
may
be used
with
120
or
240
volts
AC
,
50
or
60
hertz
;
or
with
125
or
250
volts
DC
.
If
120
or
125
volts
is
to
be
used
,
apply
power
to
terminals
1
and
2
.
higher
voltage
(
240
or
250
volts
)
is
to
be
used
,
apply
power
to
terminals
1
and
3
.
If
a
The
IRT
51
G
and
IRT
51
H
relays
have
a
0.2
/
2.0
amp
DC
target
seal
-
in
unit
that
is
used
in
a
circuit
with
a
normally
-
open
contact
which
will
close when
an
overtemperature
condition
is
sensed
.
For
complete
information
on
the
target
seal
-
in
unit
,
see
the
discussion
in
the
Auxiliary
Circuit Connections
section
for
IRT
51
E
.
There
are
two
normally
-
open
and
two
normally
-
closed
,
electrically
separate
contacts
in
the
auxiliary
circuit
.
One
of
the
normally
-
open
contacts
is used
in
conjunction
with
a
target
seal
-
in
unit
,
overtemperature
condition is
first
sensed
,
two
conditions
are
met
:
The
contact
states
change
when
an
They
will
stay
in
this
new
state
until
12
Courtesy of NationalSwitchgear.com

GEK
-
86038
The
relay
senses
a
temperature
at
or
below the
pre
-
selected
reset
temperature
,
causing
the
right
-
hand
contact
(
IRTR
)
to
close
,
and
The
relay
is
reset
by
any
one
of
the
three methods listed
below
:
.
1
.
2
.
METHOD
1
:
Reset
can
be
accomplished
by
pushing
upward
on
the
reset
rod
located
at
the
bottom
,
left
side
of
the
relay
cover
.
METHOD
2
:
Reset
can
be
accomplished
electrically
from
a
remote
location
by
connecting
a
switch
across
terminals
19
and
20
.
When
the
switch
is
closed
,
the
relay
will
reset
;
however
,
the
target
of
the
target
seal
-
in
unit
will
still
show
if
the
target
seal
-
in
unit
had
operated
.
The
only
way
to
remove
the
target
indication
is
by
manually
pushing
upward
on
the
reset
rod
located
at
the
bottom
,
left
side
of
the
relay
cover
.
METHOD
3
:
The
relay
can
be
made
to
be
sel
f
-
resetti
ng
by
shorting
terminals
19
and
20
together
.
If
this
method
of
resetting
is chosen
,
the
target
of
the
target
seal
-
in
unit
will
still
show
if
the
target
seal
-
in
unit
had
operated
.
The
only
way
to
remove
the
target
indication
is
by
manually
pushing
upward
on
the
reset
rod
located
at
the
bottom
,
left
side
of
the
relay
cover
.
The
I
RTS
1
G
and
IRT
51
H
auxiliary
circuits
have
a
special
interlock
arrangement
This
position
will
that
will
maintain
the
last
energized
position
of
the
contacts
,
be
maintained
even
if
power
is removed
from
the
relay
.
This
special
feature
must
be
considered
when
first
placing
the
relay
into
service
or
when
returning
a
relay
back
into
service
after
completing
maintenance
on
the
relay
.
To
avoid
tripping
on
start
up
for
reasons
other
than
overtemperature
:
Apply
power
to
the
IRT
relay
Reset the
IRT
relay manually
Energize
the
equipment
which is
to
be
protected
.
1
.
2
.
3
.
This
will
ensure
that
the
relay
contacts
and
target
seal
-
in
unit
are
in
the
correct
state
for
overtemperature
protection
.
RTD
CONNECTIONS
Each
of
the
IRT
relays
has
been
designed
to
be used
with
a
specific
type
resistance
temperature
detector
.
Before
connecting
an
RTD
to
the
relay
,
make
sure
that
the
relay
is
suitable
for
use
with
the
RTD
.
This
information
is
presented
on
the
relay
nameplate
,
and
in
Table
1
of
this
instruction
book
.
The
RTDs
to
be used
with
IRT
relays
should
be
a
three wire
type
.
The leads
coming
from
the
RTDs
should
be
shielded
to
prevent
stray
fields
from
inducing
voltages
into
the
RTD
circuit
.
If
an
extension
to
the
RTD
length
is
required
,
the
extension
leads
should
be
twisted
together
.
Also
,
the
lead
extension resistance
13
Courtesy of NationalSwitchgear.com

GEK
-
86038
*
should
be
identical
for
all
three
leads
.
The
resistance
of
each
lead
to
relays
used
with
10
ohm
RTDs
must
not
exceed
0.25
ohm
(
1.0
ohm
to
relays
used
with
100
ohm
or
120
ohm
RTDs
)
.
A
decrease
in
the
operating
point
of
the
relay
of
up
to
0.8
°
C
can
be
expected
for
each
ohm
of
lead
run
to
relays
with
10
ohm
RTDs
.
(
The
decrease
can
be
up
to
0.2
°
C
for
each
ohm
of
lead
run
to
relays
using
100
ohm
or
120
ohm
RTDs
.
)
TABLE
8
LEAD
WIRE
RESISTANCE
LEAD
WIRE
SIZE
OHMS
/
FT
AT
25
°
C
DIAMETER
INCHES
AWG
NO
.
0.0016
0.0026
0.0041
0.0065
0.0104
0.0165
0.0262
0.0416
0.0666
0.1058
12
0.0808
0.0640
0.0508
0.0403
0.0320
0.0253
0.0201
0.0159
0.0126
0.0100
14
16
18
20
22
24
26
28
30
Should
it
become
necessary
to
switch
the
relay
from
one
RTD
to
another
by
a
switching
scheme
,
arrange
the
switching
circuit
to
remove
the
lead
from
stud
6
first
and
restore
it
last
.
This
procedure
will
avoid
nuisance
tripping
during
the
switching
operation
.
At
the
time
of
installation
,
visually
check
the
relay
for
tarnished
contacts
,
loose
screws
,
foreign
matter
within
the
case
,
or
any
other
physical
imperfections
.
If
any
of
these
are
found
,
they
should
be
corrected
immediately
.
INSPECTION
,
ACCEPTANCE
TESTS
,
PERIODIC
CHECKS
AND
ROUTINE
MAINTENANCE
Immediately
upon
receipt
of
the
relay
,
it
should
be
inspected
and
tested
to
make
sure
that
no
damage
has
been
sustained
in
shipment
and
that
the
relay
calibrations
have
not
been
disturbed
,
protective
relays
in
the
operation
of
a
power
system
,
it
is
important
that
a
periodic
test
program
be
followed
.
The
interval
between
periodic
checks
will
vary
depending
upon
environment
,
type
of
relay
and
the
user
'
s
experience
with
periodic
testing
.
interval
best
suited
to
his
individual
requirements
,
it
is
suggested
that
the
the
following
inspections
and
tests
be
performed
at
the
time
the
relay
is
received
,
and
then
repeated
once
a
year
thereafter
.
Also
,
in
view
of
the
vital
role
of
Until
the
user
has
accumulated
enough
experience
to
select
the
test
VISUAL
INSPECTION
Remove
the
relay
from
its
case
and
check
that
there
are
no
broken
or
cracked
parts
or
any
other
indications
of
damage
.
Check
that
the
internal
parts
of
the
relay
are
clean
and
that
there
is
no
foreign
matter
within
the
relay
.
*
Revised
since
last
issue
14
Courtesy of NationalSwitchgear.com

GEK
-
86038
MECHANICAL
INSPECTION
AND
ADJUSTMENTS
Moving
Contact
Assembly
1
.
There
should
be
no
noticeable
friction
when
the
disk
is
slowly
rotated
clockwise
.
The
disk
should
return
by
itself
to
its
rest
position
against
the
right
stationary
contact
or
moving
contact
stop
.
If
a
tendency
to
bind
or
excessive
friction
is
evident
,
check
for
obstructions
to
the
disk
travel
.
Dirt
and
metallic
particles
in
the
drive
magnet
unit
or
drag
magnet
air
gaps
can
interfere
with
the
disk
motion
.
2
.
The
disk
shaft
should
have
a
vertical
end
play
of
1
/
64
inch
to
1
/
32
inch
.
The
disk
does
not
have
to
be
in
the
exact
center
of
either
the
drive
magnet
or
the
drag
magnet
air
gaps
for
the
relay
to
perform
correctly
.
Should
the
disk
not
clear
all
of
the
air
gaps
,
or
if
the
end
play
is
not
1
/
64
to
1
/
32
of
an
inch
,
perform
the
following
adjustment
:
End
play
and
disk
position
is
determined
by
the
relative
positions
of
the
lower
jewel
bearing
and
the
upper
pivot
.
Both
the
bearing
and
the
pivot
are
held
in
position
by
set
screws
in
the
die
-
cast
supporting
frame
.
The
lower
jewel
is
to
be
located
so
the
disk
is
approximately
centered
in
the
air
gaps
of
the
drive
magnet
and
the
drag
magnet
.
The
upper
pivot
should
then
be
located
so
the
shaft
has
1
/
64
to
1
/
32
inch
end
play
.
Both
set
screws
must
be
securely
tightened
after
the
adjustment
is
complete
.
The
contacts
should
have
approximately
1
/
32
inch
wipe
.
That
is
,
the
stationary
contact
tip
should
be
deflected
about
1
/
32
inch
when
the
disk
and
moving
contact
complete
their
travel
.
The
contact
wipe
on
the
left
stationary
contact
is
adjusted
by
turning
the
screws
in
the
contact
brush
,
which
regulates
the
position
of
the
brush
relative
to
the
brush
stop
.
The
leaf
spring
on
the
stop
arm
of
the
IRT
51
E
and
the
right
side
stationary
contact
on
the
IRT
51
F
,
IRT
51
G
and
IRT
51
H
models
also
have
approximately
1
/
32
inch
wipe
.
This
wipe
can
be
adjusted
by
carefully
bending
the
flexible
arm
on
the
stop
arm
or
stationary
contact
.
Target
and
Seal
-
in
Units
3
.
The
moving
contact
assembly
should
move
freely
when
operated
by
hand
.
Both
contacts
should
close
at
the
same
time
,
spring
should
be
in
a
horizontal
plane
.
The
contact
wipe
should
be
at
least
1
/
64
inch
.
inserting
a
0.010
inch
feeler
gage
between
the
armature
and
the
pole
piece
.
The
contacts
should
be
closed
with
the
0.010
inch
feeler
gage
in
place
.
Telephone
Relay
Unit
With
the
unit
de
-
energized
,
each
normally
-
open
contact
should
have
a
gap
of
0.010
to
0.015
inch
.
1
.
2
.
The
cross
member
of
the
"
T
"
3
.
This
can
be
checked
by
1
.
15
Courtesy of NationalSwitchgear.com

GEK
-
86038
The
wipe
on
each
normally
-
open
contact
should
be
approximately
0.005
inch
.
This
gap
can
be
checked
by
inserting
a
0.005
inch
feeler
gage
between
the
armature
and
the
pole
piece
and
operating
the
armature
by
hand
.
The
normally
-
open
contacts
should
make
with
the
0.005
inch
feeler
gage
in
place
.
The
contact
pressure
should
not
be
less
than
ten
grams
,
measured
at
the
contact
tips
.
2
.
3
.
4
.
Check
for
roughness
or
binding
on
the
interlocking
arms
on
the
latching
telephone
relay
unit
on
the
IRT
51
G
and
IRT
51
H
models
.
Use
a
fine
file
to
dress
the
interlocking
arms
only
if
binding
or
roughness
is
observed
.
CONTACT
INSPECTION
AND
CLEANING
All
contacts
should
meet
in
alignment
.
1
.
Check
for
contact
condition
.
If
tarnishing
or
mild
pitting
is
observed
,
the
contacts
should
be
reconditioned
with
a
flexible
burnishing
tool
.
A
burnishing
tool
is
a
flexible
strip
of
metal
with
an
etched
-
roughened
surface
,
resembling
a
superfine
file
.
The
polishing
action
is
delicate
so
that
no
scratches
are
left
,
yet
corrosion
and
mild
pitting
are
cleaned
thoroughly
and
quickly
.
Its
flexibility
assures
the
cleaning
of
the
actual
points
of
contact
.
Do
not
use
a
knife
edge
,
file
,
abrasive
paper
or
cloth
to
clean
relay
contacts
.
2
.
AUXILIARY
BRUSHES
CAUTION
Every
circuit
in
the
IRT
51
drawout
case
has
an
auxiliary
brush
,
especially
important
on
current
circuits
and
other
circuits
with
shorting
bars
that
the
auxiliary
brush
be
bent
high
enough
to
engage
the
connecting
plug
or
test
plug
before
the
main
brushes
do
.
current
transformer
secondary
circuits
from
being
opened
or
the
current
circuits
from
being
interrupted
.
It
is
This
will
prevent
the
RHEOSTAT
CLEANING
Although
the
sliding
contact
in
the
temperature
selection
rheostat
is
resistant
to
tarnishing
,
it
is
not
immune
to
tarnishing
and
should
be
cleaned
as
part
of
the
normal
relay
maintenance
program
,
several
times
will
mechanically
clean
the
slider
tip
contact
within
the
rheostat
and
will
usually
be
adequate
.
If
a
more
thorough
cleaning
is
required
,
a
good
quality
liquid
contact
cleaner
can
be
used
.
Turning
the
temperature
dial
back
and
forth
ELECTRICAL
TESTS
All
alternating
current
operating
devices
are
affected
by
frequency
.
Since
non
-
sinusoidal
waveforms
can
be
analyzed
as
a
fundamental
frequency
plus
harmonics
of
the
fundamental
frequency
,
it
follows
that
alternating
current
devices
,
such
as
the
IRT
type
relays
,
will
be
affected
by
the
applied
waveform
.
The
purity
of
the
sine
wave
,
that
is
its
freedom
from
harmonics
,
cannot
be
expressed
as
a
finite
number
for
any
particular
relay
.
Therefore
to
test
alternating
current
relays
,
it
is
essential
to
use
a
sine
wave
of
current
or
voltage
of
the
correct
frequency
and
good
wave
form
.
16
Courtesy of NationalSwitchgear.com

GEK
-
86038
Relays
to
be
used
with
direct
current
power
should be
tested
using
a
good
direct
current
power
supply
,
not
full
wave
rectified
power
.
Unless
the
rectified
power
supply
is
well
filtered
,
that
is
,
there is
less than
5
%
ripple
,
the
IRT
auxiliary
circuits
may
behave
slightly
different
when
tested
with
a
power
supply
that
is
substantially
different
than
the
system
power
supply
.
Since
all
type
IRT
relays
that
are
in
service
operate
in
their
case
,
they
should
be
tested
in
their
case or an
equivalent
steel
case
.
In
this
way
,
any
magnetic
effects
of
the
enclosure
will
be
duplicated
during testing
.
Before
testing
is
begun
,
check
that
the
relay
is
level and
in
a
vibration
-
free
environment
.
In
addition
,
the
relay
should
have
the
cover
on
and
power
applied
at
rated
voltage
and
frequency
to
the
operating
circuit
for
approximately
30
minutes
prior
to
actual
temperature
point
testing
.
During
the
30
minute
warm
up
period
,
there should be
a
simulated
RTD
load
on
terminals
4
,
5
and
6
.
Selection
of
Simulated
RTD
Load
*
To
choose the value
of
this
simulated
RTD
load
,
select
the
temperature
at
which
relay
operation
is
desired
.
The
relay
is
calibrated
in
degrees
centigrade
.
Figure
16
may
be
used
to convert
Fahrenheit
to
Centigrade
if
temperature
is
known
in
Fahrenheit
.
Go
to
Figure
13
,
14
,
or
15
,
depending
upon
the
type
of
RTD
for
which
the
IRT
relay
has been
designed
(
10
ohms
at
25
°
C
copper
,
100
ohms
@
0
°
C
platinum
,
or
120
ohms
@
0
°
C
nickel
)
.
Select
a
resistor value
equal
to
the
simulated
RTD
load
resistance associated
with
the
desired
operating
temperature
.
This is the resistance
to
be used
as
the
simulated
RTD
load
.
Measure
the
resistance
of
the
resistor
very
carefully
,
since
a
small
difference
in
resistance values
can mean
several
degrees
difference
between what
is
desired
and what
is
actually
obtained
.
During
the
30
minute
warm
up
period
,
set
a
temperature
on
the
temperature
selection
dial
just
over
the
temperature
associated
with
the
simulated
RTD
load
.
The
relay
should
not
close
the
IRT
|
_
(
overtemperature
)
contact
.
Apply
power
at
rated
voltage
and
frequency
to
the
auxiliary
circuits
.
After
the
30
minute
warm
up
period
,
adjust
the
temperature
selection dial
to
the
temperature
associated
with
the
resistance
of
the
simulated
RTD
load
,
relay
overtemperature
contact
(
IRT
|
_
)
should close
within
2
°
of
the
relay
setting
.
If
it
does
not
,
see
the
CALIBRATION PROCEDURE
section
.
The
The
IRT
51
F
,
IRT
51
G
and
IRT
51
H
relays
have
a
reset
temperature
contact
(
IRTR
)
.
When the
relays
are
shipped
from
the
factory
,
the
reset
temperature
is
adjusted
to
10
OC
below
the
temperature
dial
selection
temperature
.
To
change
this
reset
temperature
,
the
contact
gap
distance
must
be
changed
by
loosening
the
locking
screws
of
the low
temperature
contact
dial
,
and
turning
the
dial
.
Turn
the
dial
counterclockwise
(
opening
the
contact
gap
)
to
decrease the
reset
temperature
,
or
turn
it
clockwise
(
closing
the
contact
gap
)
to
raise
the
reset
temperature
.
Tighten
the
locking
screws
after
adjusting
the
contact
gap
.
To check
the
reset
temperature
setting
,
choose
a
simulated
RTD
resistance
that
corresponds
to
the
desired
reset
temperature
.
The
IRTR
(
reset
)
contact
should close
within
2
°
of
the
desired
reset
temperature
.
*
Revised
since
last
issue
17
Courtesy of NationalSwitchgear.com

GEK
-
86038
Check
that
the
auxiliary
circuits
function
as
designed
and
that
the
reset
mechanisms
function
properly
.
CALIBRATION
PROCEDURE
The
IRT
relays
have
been
calibrated
at
the
factory
and
the
calibration
settings
should
not
require
any
additional
adjustment
.
Recalibration
should
be
considered
only
after
all
of
the
checks
,
tests
and
servicing
notes
,
including
cleaning
the
temperature
selection
dial
rheostat
,
have
been
accomplished
.
If
the
relay
still
shows
that
it
is
out
of
calibration
after
the
tests
,
checks
and
service
listed
in
the
INSPECTION
,
ACCEPTANCE
TESTS
,
PERIODIC
CHECKS
AND
ROUTINE
MAINTENANCE
section
of
this
instruction
book
have
been
completed
,
proceed
as
follows
:
Remove
all
windup
from
the
induction
disk
spring
so
that
the
moving
contact
in
the
relaxed
position
just
makes
contact
with
the
left
stationary
contact
.
Wind
the
spring
counterclockwise
90
°
.
The
ring
may
be
turned
by
inserting
a
screwdriver
in
the
notches
around
the
edge
.
The
notches
are
spaced
at
about
30
°
increments
.
This
windup
will
cause
the
moving
contact
to
touch
the
right
stationary
contact
or
the
moving
contact
stop
.
Set
the
adjustable
tap
(
slide
band
)
on
R
2
to
a
position
at
the
center
of
the
adjustable
range
of
the
resistor
.
Using
AWG
No
.
12
or
larger
diameter
wire
,
with
a
maximum
wire
length
of
12
inches
,
connect
resistor
A
from
Table
9
across
terminals
4
and
5
.
Short
terminals
5
and
6
together
.
1
.
2
.
3
.
4
.
5
.
Turn
the
temperature
selection
dial
to
the
160
°
C
setting
.
6
.
Apply
rated
voltage
and
frequency
to
the
operating
circuit
.
7
.
Adjust
R
1
until
the
moving
contact
just
makes
the
left
IRT
stationary
contact
(
IRT
i
_
)
.
Tighten
the
slide
band
in
this
position
.
If
the
R
1
sliding
tap
does
not
permit
this
setting
precisely
,
adjust
the
spring
windup
until
this
setting
is
achieved
.
It
is
important
that
the
windup
adjustment
not
exceed
±
30
°
from
the
previously
set
90
°
windup
position
.
No
further
adjustment
to
the
windup
spring
is
permitted
after
this
adjustment
is
made
.
Disconnect
power
from
the
operating
circuit
,
it
with
resistor
"
B
.
"
the
temperature
selection
dial
to
80
°
C
.
circuit
.
8
.
Remove
resistor
"
A
"
and
replace
Terminals
5
and
6
should
remain
shorted
together
.
Reapply
power
to
the
operating
Set
9
.
Adjust
the
slide
band
on
resistor
R
2
until
the
IRT
left
stationary
contact
(
I
RT
L
)
and
the
moving
contacts
just
make
,
position
.
Tighten
the
slide
band
in
this
10
.
Disconnect
power
from
the
operating
circuit
.
Remove
resistor
"
B
"
and
replace
it
with
resistor
"
C
,
"
or
with
a
resistor
having
a
resistance
that
corresponds
to
the
resistance
of
an
RTD
at
some
selected
temperature
.
See
Selection
of
Simulated
RTD
Load
for
resistor
value
selection
method
.
Terminals
5
and
6
should
remain
shorted
together
.
Reapply
power
to
the
relay
.
Set
the
18
Courtesy of NationalSwitchgear.com

GEK
-
86038
temperature
selection
dial
to
120
°
C
if
resistor
"
C
"
was
chosen
,
or
to
the
temperature
that
is
associated
with
the
resistance
value
chosen
if
a
value
other
than
resistor
"
C
"
is
selected
.
The
left
IRT
contacts
(
IRT
|
_
)
should
close
within
±
2
°
C
of
the
selected
temperature
dial
setting
.
This
completes
the
overtemperature
calibration
procedure
.
TABLE
9
*
CALIBRATION
RESISTOR
VALUES
RTD
TYPE
(
Ohms
)
RESISTOR
"
A
"
RESISTOR
"
B
"
RESISTOR
"
C
"
10
15.5
ohms
12.4
ohms
14.0
ohms
100
165
134
149
120
188
265
223
11
.
The
IRT
51
F
,
IRT
51
G
and
IRT
51
H
models
are
equipped
with
a
reset
temperature
contact
(
IRTR
)
.
This
contact
has
been
set
at
the
factory
to
close
when
the
sensed
temperature
falls
to
10
°
C
or
more
below
the
temperature
selected
on
the
temperature
selection
dial
.
The
reset
temperature
may
be
adjusted
to
any
temperature
between
5
°
C
and
30
°
C
below
the
temperature
shown
on
the
temperature
selection
dial
.
The
procedure
to
do
this
is
as
follows
:
After
completing
step
10
,
which
identifies
the
overtemperature
calibration
point
,
mark
the
location
of
the
temperature
selection
dial
.
Do
not
disturb
this
dial
setting
until
the
reset
temperature
calibration
is
complete
.
Next
,
determine
the
reset
temperature
with
respect
to
the
overtemperature
setting
.
For
example
,
the
overtemperature
setting
that
is
required
for
a
particular
application
is
120
°
C
and
the
desired
reset
temperature
is
liooc
.
The
temperature
difference
between
the
two
is
10
°
C
.
Using
the
appropriate
chart
(
see
Figures
13
,
14
or
15
)
select
a
resistance
value
that
corresponds
to
a
temperature
that
is
10
°
C
lower
than
the
overtemperature
calibration
point
that
was
determined
in
step
10
.
Connect
this
resistance
value
in
the
place
of
resistor
"
C
.
"
To
set
the
reset
point
,
the
IRTR
contact
gap
must
be
adjusted
.
The
wider
the
gap
is
made
,
the
lower
the
reset
temperature
.
To
change
the
IRTR
contact
gap
,
loosen
the
two
locking
screws
of
the
IRTR
contact
position
dial
.
Rotate
the
dial
until
the
right
contact
and
the
moving
contact
just
make
.
Tighten
the
two
locking
screws
.
This
sets
the
reset
temperature
and
completes
the
reset
temperature
calibration
procedure
.
*
Revised
since
last
issue
19
Courtesy of NationalSwitchgear.com

GEK
-
86038
RENEWAL
PARTS
Sufficient
quantities
of
renewal
parts
should
be
kept
in
stock
for
the
prompt
replacement
of
any
that
are
worn
,
broken
or
damaged
.
When
ordering
renewal
parts
,
address
the
nearest
sales
office
of
the
General
Electric
Company
.
Specify
the
name
of
the
part
wanted
,
quantity
required
,
and
complete
nameplate
data
of
the
relay
.
20
Courtesy of NationalSwitchgear.com