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the main induction disk u nit, a s shown in Figure 9.
normal l y-open output c ontact s wheneve r the detected tem perature exceeds the set '
v al ue .
These output c ontacts c a n be reset:
a .
ma nua l l y
b .
el ectric a l l y
c .
sel f-reset by mea n s of exte rna l c o n nection s
but on l y afte r the detected tem pe rature has fal l en bel ow the reset tempe rature o f
the main unit a n d it s right-hand (IRT R ) contac t has c l osed .
main
unit
is
continuous l y
tempe rature l evel .
case .
The type IRT51H is simil a r to the IRT 5 1G except a n RT D probe a s sembl y is
fu rn ished a s a pa rt of the rel a y model .
tip sensitive, 100 ohm at o o c, pl atinum RTD .
i n stal l ation fittin g a nd al so a b ra s s reducing fittin g for use where required (see
INSTALLATIO N PRO CEDURE).
The type IRT5 1 rel ays c a n be used to protect any a p pa ratus equip ped with one o f
the re sista nce temperature detectl1rs l isted in the INT RODUCTION sectio n .
IRT51E and IRT51F rel ays a re inten ded prima ril y for the protection of moto r s or
gene rato rs havin g the RTo•s embedded in the windin gs .
of so o c to 16 50C make s them pa rticul a r l y suitabl e for a p p l ication o n m achine s with
c l a s s A , B or F insul ation .
t ran sformers a gain st overheatin g with a s socia ted RTO•s pl aced i n stra te gic l ocation s
in the ta nk .
Typic al extern a l con nection s for the type IRT51E rel ay a re shown in Figure 10 .
Typic al external con nection s for the type IRT51F rel ay a re shown in Figure 11.
The
types
IRT51G
tempe rature protection of rotati n g equipment .
these rel ays are shown in Figure
The functions that temperature re l ays pe r fo rm depe nd upon the type of equipment
to be protected, its im port a nce to the system, a n d its l oc ation in the system .
unattended
stations,
embedded RTo•s may be used to reduce or remove l oa d automatic al l y .
with it s n ormal l y- o pe n
empl oyed to prevent an inc rea se in l oa d until the tem pe ratu re ha s returned to an
acceptabl e l evel .
In attended station s, the function of these rel ays is genera l l y to provide a
wa rnin g al arm that an overtem pe rature condition exists, es pecia l l y in the c a se of
majo r unit s and esse ntia l auxil iary power equi pment.
a l a rm, the rel ays may a l s o initiate a timing device which c auses a del ayed automatic
corrective action if the station o pe rato r has n ot re s po nded to the a l a rm within a
rea sonabl e time .
These rel ays shoul d n ot be used to dete rmine machi ne l oad, s inc e o pe ratin g
tem perature is not necessa ril y a rel iabl e i ndication of ma ximum permi s sib l e l oad .
Other design l imitat ion s may pl ace more st
GEK-86038
a dju stabl e
The IRT51G rel ay is mounted in a d oub l e end, sma l l size d rawout
APPL I CATION
These rel ays may a l s o be a ppl ied to protect powe r
a nd
IRT51H
rel ays
12.
for
exampl e,
the IRT51E
(IRT L )
a nd n o rmal l y-c l osed (IRT R )
The rel ay operates to c l o se the
s o c
to
30 0C
from
The p robe is a th ree wire, sin g l e el ement,
The probe c omes with a f l uid seal
The usabl e tem pe rature ra nge
intended
a re
Typical
external
o r IRT51F
In addition to s ounding an
4
inge nt rest rictio n s on mac hine ratin g .
The reset l evel o f the
bel ow
its
o pe rating
The types
prima ril y
for
bea rin g
c o n nections for
o pe rati n g
rel ays
The type IRT51F
contact s coul d a l s o be
In
from
V
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