GE GCX51A - Control Spring Adjustment; Ohm Unit; Reach and Angle - of - Maximum - Torque Adjustment

GEI
-
98328
Adjustment
of
rheostat
R
3
has
a
secondary
effect
on
the
angle
of
maximum
torque
,
and
adjustment
of
R
4
likewise
effects
the
reach of
the
unit
.
Therefore
,
for
very
accurate
settings
it
is
necessary
to
recheck
the
reach after the
angle
of
maximum
torque
has been
set
,
and
to
continue
readjustments
until
the reach and
angle
of
maximum
torque
are
both
within
the
limits
specified
above
.
NOTE
:
OHM
UNIT
a
.
Control
-
Spring
Adjustment
Make
sure
the
relay
is
well leveled
in
its
upright
position
,
of
a
thin screwdriver
into
one
of
the slots
in
the
edge
of
the
spring
-
adjusting
ring
,
and
set
the
ring
so
that
the
moving
contact
just
touches
its
backstop
.
With
the
proper
adjustment
,
if
the
backstop
is
backed
off
,
the
moving
contact
will
not
follow
.
Insert
the
blade
It
is
recommended
that
the
control
-
spring
adjustments
for
both
the
OHM
and
MHO
units
be checked
with
the
relay
mounted
in
its final
position
on
the
panel
.
NOTE
:
Reach and
Anqle
-
of
-
Maximum
-
Torque
Adjustment
b
.
The
basic
minimum
reach of the
OHM
unit is
controlled
by
rheostat
Ri
,
and
its
angle
of
maximum
torque
(
90
°
current
lagging
voltage
)
may
be
adjusted
by
means
of rheostat
R
2
.
It
should
be
noted
,
however
,
that
these
adjustment
are
not
independent
;
that
is
,
an
adjustment
of
R
2
will
have
some
effect
on
the
reach of
the
OHM
unit
,
and
adjustments
of
Ri
will
affect the
angle
of
maximum
torque
.
To
calibrate
the
OHM
unit
,
place
the
No
.
1
taps
in
the
100
%
position
and
use
the
connections
shown
in
Figure
10
.
Follow the
procedure
outlined
below
:
Step
1
:
With
current set at
5
amps
and
voltage
at
120
V
,
adjust
the
phase
shifter
so
that the
phase
-
angle
meter
reads
270
°
(
i
.
e
.
,
current
lags voltage
by
90
°
)
.
Then
set
the
current
for
the
value
listed
in
the column
headed
"
90
°
"
in
Table
XIV
.
example
,
for the
0.2
ohm
basic
minimum
reach
,
the
current
would
be
set at
15
amps
and
the
voltage
at
6
V
.
Adjust
Ri
rheostat
until
the
OHM
unit
contacts
just
close
.
Now
raise
the
voltage
and
again
lower
it
slowly
until
the
OHM
unit
contacts
just
close
.
The
voltage
at
the
operating
point
should
be
within
+
1
%
of the
voltage
listed
in
Table
XIV
in
the column
headed
"
90
°
"
.
Readjust
Ri
until
the
operating
voltage
is
within
the
+
1
%
limit
.
For
The
relay
operating
circuit
should
not
be
left
energized
with
the
test
currents
of
Table
XIV
for
more
than
a
few
seconds
at
a
time
.
NOTE
:
28
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