GEH-1786 Reclosing Relay Type
ACR
energizing
the
"Reset"
coil of 179E. The clutch
.
release
unit 179R
is
released
by the opening of the
179E2
contacts.
The
reclosing
relay
is
now
ready
•-
initiate
an
immediate
reclosure
in the event of a
sequent opening of the
circuit
breaker.
vELA
YED RECLOSURES
If
the
circuit
breaker
trips
again, following the
immediate
initial
reclosure
the open 152al switch
prevents
the
reset
of the
relay
when the "MN"
contact
is
operated
by
cam
"E".
Consequently the
relay
continues to operate until the
first
delayed
reclosure
point
is
reached,
as
determined by the
settings
of the double-ended
cams
"D" on the
front
dial
hub. The anti-pump unit 179Z will pick
up
as
soon
as
the 152b switch indicates
that
the
breaker
has
tripped
again. Consequently, the operation of
the "AB-BC" contact combination ("AB"
closes,
"BC"
opens) by one of the "D"
cams,
completes the
reclosing
Circuit, thus energizing the closing
relay
152X. Even a momentary opening of the 152b switch
will
cause
the 179Z unit to drop out, breaking
its
seal-in
circuit.
Therefore
only one
reclosure
of
the
circuit
breaker
is
possible for each operation
of the "AB-BC" contacts.
When the
cam
projection
passes
and allows
the
"AB-BC" switch to
reset,
the 179Z unit will again
operate
if
the 152b switch
is
closed, thus setting
the
circuit
for subsequent delayed
reclosures.
At a definite time interval of approximately
10
seconds,
after
the operation of the "AB-BC"
'tacts
by a
cam
projection "D", the opposite end
he
same
cam
plate
operates
the "MN" contact
J.
79.
If
the 152al
is
closed the
circuit
responds
as
described
in the section entitled RESET, and the
relay
will
return
to
its
reset
position.
If
the
circuit
breaker
has
retripped
as
the
result
of a
susiained
fault, the 152al switch will be open andthe
relay
will
continue through
its
cycle until the next delayed
re-
closure
point
is
reached, whereupon the sequence
previously
described
Is repeated.
LOCKOUT
If
none
of
the
attempts
to
reclose
the
breaker
is
successful,
the
relay
continues to
operate
until
the lockout position
is
reached. Lockout
results
from
the operation
of
the "GH-HI" switch ("GH"
opens, "HI"
closes)
by
a notch
In
the auxiliary
cam
shaft, and Is indicated by the simultaneousoperation
of the
alarm
coniact
"JK".
In
the lockout position
of
the
relay,
the motor
circuit
Is
transferred
through coniact
"Hr'
to the
152A2 switch. Thus a successful manual
reclosure
of the
circuit
breaker
restarts
the motor which will
run
for
a
short
period
(approximately five seeonds)
until contact "MN"
is
operated by the fixed
cam
"F".
This
completes the
reset
circuit
and
causes
the
relay
to
reset
as
previously
described.
ThE'
operating cycle described above
represents
...,ical setting
of
the
relay.
Many
other
settings
possible
some
of
which
are
described
under
JuJJUSTMENTS. Fig. 6
illustrates
clearly
the
sequence
of
the
cam-operated
contacts
deseribed
10
above. Note
that
the
diagram
shows minimum
allowable
intervals
between the
various
operations•
The
elementary
diagram,
Fig. 4 shows the
application
of
the
reclosing
relay
In
a typical
•.
pneumatic mechanism control
scheme.
The
operat-
ing functions of the
ACR
relay
are
the
same
as
previously
described
for the solenoid operated
mechanism. The two
schemes
are
therefore
similar,
except for the different types of controlling devices
used
In
the pneumatic mechanism to accomplish
its
tripping and
reclosing
operations.
INSPECTION
When
the Type
ACR
reclosing
relay
Is
received,
the following points should
be
checked
prior
to •
installation, with the
cradle
removed from the
case.
Press
in the
manual
release
rod
projecting
through the
center
of the dial plate,
releasing
the
crown-gear
clutch. With the
release
rod held in,
turn
the dial hub by hand through Its complete
op-
erating
range
of apprOximately 180 degrees. The
gear
train
should
operate
freely
against
the
restraint
of the
reset
spring.
The dial
cams
"D" and
"E"
should
operate
the front switches "AB-BC" and
"MN" providing approximately
1/64
Inch
overtravel
of
the
roller
actuator
after
the switch has operated.
When the locked-out position
is
reached, the lockout
and
alarm
contacts on the cam
shaft
will be
heard
operating.
If
the
dial
hub
is
turned
further,
to a point
slightly beyond lockoutl the "MN" switch should be •
operated
by
the fixed 'F" cam.
If
the dial hub
is
now
released,
with the
release
rod
still
pushed in,
the dial hub and
gear
train
should
return
all
the
way to
their
reset
position under the influence
of
the
reset
spring.
If
the
relay
Is to provide Immediate initial
reclosure,
the "AB" contact
must
be closed when
the
relay
is
In
the
reset
position. This
is
ac-
complshed
by
setting
one
of
the single-ended
"E"
cams
to
operate
"AB-BC" when the
relay
resets.
Turn
the dial hub a few
degrees
away from
reset
and check
that
"AB" opens
as
the hub Is turned.
Let
the hub
return
slowly and check that "AB"
operates.
When the
relay
is
in
its
reset
position switch
"DE"
on
the
cam
shaft
should be in the operated •
position. To check this, turn the dial
hub
a few
degrees
away
from
reset
and then
let
it
return
slowly, listening for the click of switch "DE".
The
armature
of the clutch
release
unit Is
accessible
from
the
rear
of the
cradle.
Grasp the
armature
between index finger and thumb and pull
it
against the pole piece, disengaging the clutch.
Check that the
seal-in
switch, 179R, clicks slightly
before the
armature
strikes
the pole-piece.
Release
the
armature
slowly
at
the
same
time turning the
front
dial hub by
means
of
the knurled knob,
so
that
•
the crown
gears
re-engage
on the tips
of
their
.
teeth. The
seal-in
switch should reopen
before
the
tips
of
the teeth meet.
