tacts of the
D
unit . Insert the tap s crew i n the m ini
m um value tap s etting and adjust the sprin g such
that the contacts wil l close as i nd icated by a neon
l am p i n the c o ntact circu i t wh e n en ergized with the
required c urrent. The pickup of the o vercurren t unit
with th e tap screw is any other tap shoul d be within
:t
5 % o f tap val u e .
If adjustment o f pick-up current i n between tap
settings is desired insert the tap screw in the next
lowest tap setting and adjust the spring as described.
It should be noted that this adjustment results in a
sl ightly different time characteristic curve and burden.
Directional Unit (D)
The directional unit is the lo wer cylinder unit.
1.
The upper bearing screw should be screwed
down until there is approximately
.025"
clearance
between it and the top of the shaft bearing. The upper
pin bearing should then be securely locked in posi
tion with the lock nut.
2. Contact g ap adj u stment
for
the directional
unit i s m a d e wi t h t h e moving cont act i n the reset
po si t i o n , i . e. , against t h e right si de
o f the
bridge.
Advan c e the ri ght h and stationary c o ntact until the
cont acts j u st cl o se . Then advan c e
the
stationary
contact an addi tion al o n e-h al f turn.
No w m o v e in t h e
I
e ft
-
h
an
d stationary contact
until i t j u st to uch e s th e moving contact. Th en back
o ff t h e station ary contact 2/ 3
of one turn for
a co n
t ac t g ap
of
. 0 20 " . The cl amp
holding
the statio nary
ccntact h o u si n g n e ed not be l o o sened
for
the adj u st
m ent since the cl amp util i zes a spring-typ e action in
hoi ding
the stationary contact
i n po sitio n.
3. Insert tap screw of overcurrent unit in highest
tap. The sensitivity adjustment is made by varying
the tension of the spiral spring attached to the mov
ing el ement assembly. The spring is adjusted by pl ac
ing a screwdriver or similar tool into one of the
notches located on the p eriphery of the spring adjust
er and rotating it. The spring adi.uster is located on
the underside of the bridge and is held in place by a
spring type clamp that do es not have to be loosened
prior to making the necessary adjustments.
The sp ring i s to be adj usted such that the con
tact will clo s e as indi c ated by a neon l amp in the
co11tact ci rcuit when en ergi zed with 1 . 2 volts and 4
an1ps ( current l eading 30 °) fo r the 4 to 1 2 amp ere
range r el ay s and 1 . 2 volts and 2 amp s for the 0 . 5 to
2. 5 and 2 to 6 amp ere range rel ays. Thi s can be done
app ro ximately using current in p hase with voltage by
increasi ng the p i ck up current to 4 . 6 and 2. 3 amp eres
20
respectively.
*
4 . The magnetic plugs and core are used to
reverse any unwanted spurious torques that may b e
present w h e n the relay is energized respectively
on current or voltage alon e .
The reversing of the spurious torques is accom
plished by using the adj ustin g plugs and core in the
following mann e r :
t t
Apply 1 2 0 VAC 6 0 Hz t o terminals 6 and
7 .
Re
lay contacts should stay ope n . If the c ontacts are
c losed rotate core by m eans of adjustor located on
the bottom side of the cy linder unit until contacts
stay open . The c ore assembly is held in position by
the clam ping action of two c ompressed springs . This
allows its position to be changed by ins erting a non
m agnetic tool into the slot on the bottom side of
the unit.
Short circuit the v oltage terminals and apply
c urrent to the operating c ircuit terminals as per
Table 2 .
Plug adjustment i s then made per Table 2 such
that the spurious torqu es are revers e d . The plu gs
are held in position by u pper and lower plug clips .
These clips need not be disturbed in any manner
w hen making the necessary adjustment.
The magnetic plug adj ustment m ay be util ized
to positively close the contacts on current alone .
This may be d e sired on some ins tallations in order
to insure that the relay will always trip the breaker
on zero potential.
Time Overcurr ent Unit ( CO)
1) Contacts - The index mark on the movement
frame will coincide with the "0" mark on the time
dial when the stationary contact has moved through
approximately one-half of its normal deflection.
Therefore, with the stationary contact resting against
the backstop, the index mark is offset to the right of
the "0" mark by approximately
. 0 20 " .
The place
ment of the various time dial positions in line with
the index mark wil l
give
operating times as shown on
the respective time-current curves.
2 )
Minimum
Trip
Current - The adjustment of
the spring tension in setting the minimum trip current
value of the relay is most conveni ently made with the
damping magnet removed.
With the .time dial set on "0 " , wind up the spiral
spring by means of the spring adjuster until approxi
mately
6-3/4
convolutions show.
www
. ElectricalPartManuals
. com
