.1
GEK-86038
TEMPERATURE
RELAY
TYPES:
IRT51E
IRT51F
IRT51G
IRT51H
DESCR IPTIO N
�-
INT RODUCTION
The type IRT temperatu re sensing rel ays a re designed fo r use with singl e el emer
th ree l ead , resistance tempe ratu re detecto rs (RTD) .
M odel s a re avail abl e for use wi
the fol l owing specific type
RTD:
a . 10 ohm at 2soc c o p pe r
RTD
b . 100 ohm at ooc pl atinum
RTD
c . 120 ohm at ooc nickel
RTD
The model s a re l isted in Tabl e 1 .
The type IRT rel ays wil l provide overtemperatu re protection , either trip o r al ar
for any a ppa ratus that is equipped with one of the l isted RTDs .
The rel ays
a
continuousl y adjustabl e over
�
temperatu re sensing range of sooc to 16 50C .
T hese rel ays a re of the wattmetric induction disk type and provide va rious c onta
combinations as desc ribed bel ow .
The measuring circuit is simil a r to a Wheatsto
Bridge , except t hat two adjacent l egs of the bridge a re repl aced by transformer sec onda
windings .
The primary winding of this transfo rmer fo rms the pol a rizing c oil of
t
wattmetric unit .
The type IRTSlE rel ay is an overtemperature sensing rel ay having a sing
norma l l y-o pen c ontact. with a tar get seal -in unit , as sh own in Figu re 7 .
The rel ay
fu rnished in a singl e end , smal l size d rawout c ase .
The IRTSlF rel ay is an overtem peratu re sensing rel ay having both normal l y-o pen
a
norma l l y- c l osed output contacts.
These c ontacts a re provided by an au xil iary unit (
o perating from the main induction disk unit c ontacts in a pickup , seal -in knock do
circuit , as shown in Figu re 8 . The rel ay is sel f-resetting when the detected temperatu
fal l s bel ow a p resel ected l evel .
This reset temperatu re is c ontinuousl y a djustabl e ov
a range from soc to 300C bel ow the set o perating temperatu re .
A manua l reset ta rget
incl u ded , which is o perated by a c ontact of the au xiliary unit A . The rel ay is mount
in a singl e end , smal l size d rawout c ase .
The type IRTSl G is an overtem peratu re sensing rel ay providing two n o rma l l y-a�
and two norma
11
y-cl osed el ectri c a
11
y sepa rate o utput c ontacts .
These c ontacts
a
provided by a two-position l atching rel ay whose o perating c oil (OP) and reset c oil
(R
a re cantral l ed by the
1
eft-hand ( IRTL) and right-hand ( IRTR)c ontacts , respectivel y,
Thes� instructlons do not purport to cover all d�tails or variations in equip.-nt nor to provid� for
�very
possible
conting�ncy
to b� met in connection with installation,
operation or .. in
te
nanc
e
:
Should
further inforrrwttion
b� desired or should particular p robl�ms arise which ar� not covered
su//icJently t
o
r
the purchaser's purposes, the rrwttter should
be
re
f�
rr
ed
to the
General
Electric Co�any.
To the •.rtent required the products
described
herein Jlleet applicable
ANSI
•
Il:l:l:
Alld
N!:HA
stA11d.ards1
but no such assurance is given with respect to local codes and ordjnances
bec
a
u
s
e
they
vary
greatly.
3
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