GEK-86105
The 12XLA12A tes t plug may also be used.
Although this tes t plug allows greater
tes ting flexibility, it also requires
CT
shorting jumpers and greater care in
tes ting, since connections are made
to both
the relay and the external circuitry.
Induc tion Unit
With the tap plug in the m1n1mum position, and the time dial in t
h
e
Number 1/2
position, check that the current required to just close the contact is
within
+
5%
of the minimum pickup shown on the tap block.
The operating time from the
Number 5
time dial setting at five times minimum pickup
set ting should be within
7%
of the value shown in Figure 6.
To check the pickup
voltage
and time of the telephone relay,
OX, u
se the following
procedure.
1.
Place the tap screw of the target and seal-in unit in the
0. 2
amp tap.
This is the
upper
left
(
front view
)
unit.
2.
Block
closed
the contacts of the high-dropout
instantaneous unit.
This
is
the
upper right
(
front view
) u
n
i
t
.
3.
App
ly DC
voltage to relay
terminals
9
and
10.
T
he
telephone relay should
pick up
at
80%
or less
of
its rating.
4.
Apply rated voltage to the
OX
unit.
The contacts should close six cycles
(0.1
sec
o
n
d
)
after voltage is applied.
Units
There
are two target/seal-in units associated
with
the
IA C 66M(-)A
relay.
The
target/seal-in in the lower
l
ef
t (front view)
is
in
the induction unit/standard
instantaneous unit circuit.
The other target/seal-in is
lo
cated
in the
upper left
of the
relay
(front view) and is
in
the high-dropout instantaneous unit/OX telephone
relay circuit.
The target/seal-in units can be tested by applying
DC
current to the proper s tuds
and closing the correct contact, as listed in Table
X.
Reset the target/seal-in flag by pushing on the reset arm; then gradually apply the
DC
current until the unit picks up.
It should pick up within the values in
Table X.
Open the appropriate contact mentioned in
the
table; the unit must remain
sealed in.
Reduce
the DC
current until the
contacts of the target/seal-in unit open; this is
the
d
ro
p
out
value, and should be as listed in Table
X.
T
h
e
taps must be changed,
if
desired,
according
to
the
method
given
under
TARGET/SEAL-IN
UNIT in
the
CHARACTERISTICS AND
BURDENS
section.
12
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