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Relays to
direct current power supply, not full wave rectified power.
power supply
t
(
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
should be tested
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.
rated voltage and frequency to the operating circuit for approximately 30 minutes
t
prior to actual temperature point testing.
there should be a simulated RTD load on terminals 4, 5 and 6.
Selection of Simulated RTD L oad
which
centigrade.
temperature is known in Fahrenheit.
upon the type of RTD for which the IRT relay has been designed
25o c copper,
resistor value equal to the simulated RTD load resistance associated with the
desired
simulated RTD load.
since
difference between what is desired and what is actually obtained.
(
'
'-
During
selection dial just over the temperature associated with the simulated RTD load.
The relay should not close the IRT L (overtemperature) contact.
Apply power at rated voltage and frequency to the auxiliary circuits.
After the 30 minute warm up period,
the temperature
relay overtemperature contact (IRT L ) should close within 2°
If it does not, see the CALIBRATION PROCEDURE section.
The IRT51F,
When the relays are shipped from the factory, the reset temperature is adjusted to
100C
below
temperature,
screws of the low temperature contact dial, and turning the dial.
counterclockwise
turn
Tighten the locking screws after adjusting the contact gap.
temperature
desired reset temperature.
desired reset temperature.
*
Rev1sed s1nce last issue
be used with direct current power should be tested using
is
well filtered,
in their case or
In addition, the relay should have the cover on and power applied at
To choose the value of this simulated RTD load, select the temperature at
relay
operation
Figure 16 may be used
100 ohms @ ooc platinum,
operating
temperature.
a
small
difference
the
30 minute warm up period,
associated with the resistance of the simulated RTD load.
IRT51G and IRT51H relays have a reset temperature contact
the
temperature
the
contact
(opening the contact gap) to decrease the reset temperature,
it
clockwise
(closing
setting,
choose
GEK-86038
that is,
there is less than
an equivalent steel case.
is
desired.
The
to convert
Go to Figure 13,
or 120 ohms @ ooc nickel).
This
is
Measure the resistance of the resistor very carefully,
in
resistance
set
adjust the temperature selection dial to
dial
selection
gap distance
must be
the
contact
gap)
a simulated
RTD
The IRT R (reset) contact should close within 20of the
17
Unless the rectified
5% ripple,
During the 30 minute warm up period,
relay
is
calibrated
Fahrenheit
14,
the
resistance
to
values
can
mean
a temperature
on
of the relay setting.
temperature.
To
changed
by
loosening
to
raise
the
To check the reset
resistance
that
corresponds
a
good
the IRT
their
case,
they
In this
way,
any
in
degrees
to
Centigrade
if
or 15,
depending
(10 ohms at
Select a
be
used
as
the
several
degrees
the
temperature
The
(IRT R ).
change
this
reset
the
locking
Turn the dial
or
reset
temperature.
to
the
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