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* should be identical for all three leads.
us�d with 10 ohm RTDs must not exceed 0.25 ohm (1.0 ohm to relays used with 100 ohm
o;" 120 ohm RTDs).
can be expected for each ohm of lead run to relays with 10 ohm RTDs.
can be up to 0.2oC for each ohm of lead run to relays using 100 ohm
�
TDs.)
Shou 1 d it become necessary .to switch the re 1 ay from one RTD to another by a
switching scheme,
first and restore it last.
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.
Immediately upon receipt of the relay,
make
sure
that
no
calibrations
have
protective
relays
periodic test program be followed.
depending upon environment,
testing.
Until
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.
VISUA L INSPECTION
Remove the relay from its case and check that there are no broken or cracked
parts or any other i nd i cations of damage.
relay are clean and that there is no foreign matter within the relay.
*
Revised since last issue
A decrease in the operating point of the re 1 ay of up to 0. 8 o C
LEAD WIRE RESISTANCE
L EAD WIRE SIZE
AWG NO.
DIAMETER INCHES
12
0.0808
14
0.0640
16
0.0508
18
0.0403
20
0.0320
22
0.0253
24
0.0201
26
0.0159
28
0.0126
30
0.0100
the switching circuit
arrange
This procedure will avoid nuisance tripping during the
I NSPECT ION , ACCEPTANCE TESTS,
PER I OD I C CHECKS AND ROUTINE MA I NTENANCE
damage
has
been
not
been
disturbed.
in
the
operation
type of relay and the user1S experience with periodic
accumu 1 a ted
the
user
has
GEK-86038
The resistance of each lead to relays
TAB L E 8
OHMS/FT
AT 25° C
0.0016
0.0026
0.0041
0.0065
0.0104
0.0165
0.0262
0.0416
0.0666
0.1058
to remove
it should be inspected and tested to
sustained
in
shipment
Also,
in
view
of
a
power
system,
The interval between periodic checks will vary
enough
experience
Check that the i nterna 1
14
{The decrease
or 120 ohm
the
lead
from
stud
and
that
the
of
the
vital
role
it
is
important
that
to
select
the
parts of the
·�
6
f.
relay
of
a
test
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