MECHANICAL
LATCH
FOR 360A
SJ
Reclose contactor, and trip it electrically using each
trip solenoid separately. Checkthe coil clearing auxiliary
contact to make sure that each solenoid
Is
de-emirglzed
automatically after operating, to prevent solenqid coil
burnout. There should
be
no voltage between the ter-
minals of each trip solenoid coll after the contactor has
been opened. When tripped,
t~e
latch should move
briskly.
If
it
Is
sluggish, refe( toiMAINTENANCE.
CAUTION!
A latch
Is
somewhat like a mousetrap.
Use care to protect
fi)1gers
in
the event
of
an
accidental trip during check-out.
CHECK-OUT,
ELECTRICAL
Refer
to
,the
instructions for the electrically-held
contactor. '
MAINTENANCE
A maintenance program .should
be
established as
soon as the contactor is in¢talled and put into opera-
tion. After the contactor has been inspected a number
of times at monthly intervals, and the condition noted,
the frequency of inspecfion · can
be
increased or
decreased
to
suit the conditions found, since this will
depend upon the severity of the contactor duty: It
is
a
matter of operator judgement. ' ·
Failure
To
Latch
Or Unlatch·
First, establish that the latch operates freely without
mechanical Interference. (The ·contactor can
be
op-
erated electrically with
an
ext.e.nsion
cord,
as
described
previously under
CHECK-OUT,
MECHANICAL.
Or it
can
be
operated by hand
(1)
with a wrench
on
the end
of the contactor shaft,
(2)
by pushing down on the top
rear edge of the contactor crossbar, or
(3)
in the case
of
an
SJA contactor, by turning the yoke interlock arm
on the stub shaft clockwise;)
Remove )he
lat.ch
spring. Block the bottom solenoid
open temporarily'witha pencil
or
oth,E)r
shim
on
top of
Its
magnet
frame.
and underneath
Its
armature. Hold the
contaotor in the fully sealed-closed position by hand or
electrically, and manually close/open the latch using the
trip arm.
Th.a
latch should move easily.
If
it does not
move freely,'check the roller end
of
the latch arm
to
see
ifthe latch arm rubs againstthe armature.
To
eliminate
rubbing, loosenthe two latch mounting bolts
(B)
(Figure
3)
on the right side and move the right latch bearing
plate rearward until the latch arm clears the armature.
Re-tighten the mounting bolts. Re-check for free motion.
Next, hold the contactor
In
the fully sealed;closed
position, operate the latch with the trip arm, then release
the trip arm abruptly. The latch should fall freely into
the open position.
If
it
doesn't, the "backlash" clearance
is insufficient.
To
increase the clearance, loosen all five
latch mounting bolts
(A)
and
(B)
(Figure
3)
and tap both
the left and right bearing plates rearward a few thou-
sandths of
an
inch. Re-tighten the five bolts and
re-
check both the free-fall release and the freedom from
rubbing between the latch arm and the armature.
Re-install the latch spring. Check the overtravel of the
main vacuum Interrupters, since increasing "backlash" ·
decreases overtravel. Overtravel must not
be
below
.020
·
inch ·with worn contacts.
Remove the blocking shim from the bottom trip ·
solenoid. Check that both solen0id armatures move .
freely.
Failure
To
Latch
After making adjustments
as
outlined
In
the previous .
section, operate the contactor electrically. If
it
fails
to
latc.h:
·
a.
Qheck voltage applied
to
the contactor coil to
be
·
sure it is within 80% of coil rating. '
b.
Check setting of the L-63 normally'closed coll .
clearing auxiliary contact
to
see if
It
opens too soon •
and does not allow the contactor to close
..
far'
enough
to
latch.
c.
Make certain that the
late~
spring is properly i
in
place.
d.
Decrease the sensitivity of toe latch by loosening:
the lock nut on the latch adjustment and backing-·
off(unscrewlng) the latch adjustmentbolt one-half.
turn.
Try
again, and if latching
is
not successful,
back-off another half-turn,
etc.
until the latch
works.
Re-tighten the lock nut.
Failure
To'
Unlatch
After making adjustments
as
outlined
in
the previous ·
two sections, operate the contactor electrically. If the :
trip solenold(s) do not unlatch the mechanism:
a.
Check voltage applied
to
the solenoids
to
be
sure ·
it
is
within 80% of rated voltage.
b.
Check each solenoid coil for continuity. Replace ·
If
burned open. See Table
II.
c.
Make certain there
is
an
airgap under
each·
solenoid armature of
.120
to
.130
inch wh\)n the :
latch
is
latched. If there is no gap, the solenoid
armatures cannot move
to
push the latch arm.
d.
Increase the sensitivity of the latch qy loosening:
the lock nut
on
the latch adjustment and tighten- ·
ing (turn bolt clockwise) one-half tum.
Try
again,:
and if unlatching
is
not successful, turn bolt
I.
another half-turn,
etc.
until the solenoids unlatch '
dependably. Re-tighten the lock nut.
Failure
To
Remain
Latched
If nuisance unlatching occurs, de-sensitize the latch
adjustment as described under
Failure
To
Latch.
.
TABLE
II
-
REPLACEMENT
SOLENOIDS
Trip
Coll
Intermittent
Rating
115-120
VAC,
48
VDC
230-240
VAC;
'96-125
VDC
460-480
VAC,
230 VDC
575-600
VAC
24 VDC
Trip
Solenoid
Part
No.
5259C46G01
5259C46G02
5259C46G03
5259C46G04
5259C46G05
4
Courtesy of NationalSwitchgear.com
