GE IAC

GEK
-
86054
Therefore
,
in
order
to
test
AC
relays
properly
it
is
essential
to
use
a
test
voltage
and
/
or
current
waveform
that
is
sinusoidal
.
The
purity
of
the
sine
wave
(
i
.
e
.
,
its
freedom
from
harmonics
)
cannot
be
expressed
as
a
finite
number
for
any
particular
relay
;
however
,
any
relay
using
tuned
circuits
,
RL
or
RC
networks
,
or
saturating
electromagnets
(
such
as
time
-
overcurrent
relays
)
would
be
especially
affected
by
non
-
sinusoidal
wave
forms
.
TIME
-
OVERCURRENT
UNIT
Rotate
the
time
dial
slowly
and
check
,
by
means
of
a
lamp
in
the
circuit
,
that
the
contacts
just
close
at
the
zero
(
0
)
time
-
dial
setting
.
The
point
at
which
the
contacts
just
close
can
be
adjusted
by
running
the
stationary
contact
brush
in
or
out
by
means
of
its
adjusting
screw
.
This
screw
should
be
held
securely
in
its
support
.
With
the
contacts
just
closing
at
No
.
0
time
-
dial
setting
,
there
should
be
sufficient
gap
between
the
stationary
contact
brush
and
its
metal
backing
strip
to
ensure
approximately
1
/
32
"
wipe
.
The
minimum
current
at
which
the
contacts
will
just
close
is
determined
by
the
position
of
the
tap
screw
in
the
tap
block
at
the
top
of
the
relay
.
When
changing
the
current
setting
with
the
relay
in
its
case
,
remove
the
connection
plug
,
to
short
the
current
-
transformer
secondary
circuit
.
Next
,
screw
the
tap
screws
into
the
tap
marked
for
the
desired
current
,
and
then
replace
the
connection
plug
.
The
pickup
of
the
unit
for
any
current
tap
is
adjusted
by
means
of
a
spring
-
adjusting
ring
just
above
the
control
spring
.
See
Figure
IB
.
The
ring
may
be
turned
by
inserting
a
screw
driver
in
the
notches
around
the
edge
.
By
turning
the
ring
,
the
operating
current
of
the
unit
may
be
brought
into
agreement
with
the
tap
setting
employed
if
,
for
some
reason
,
this
adjustment
has
been
disturbed
.
This
adjustment
also
permits
any
desired
setting
intermediate
between
the
various
tap
settings
to
be
obtained
.
The
unit
is
adjusted
at
the
factory
to
close
its
contacts
from
any
time
-
dial
position
at
a
minimum
current
within
five
percent
(
5
%
)
of
the
tap
plug
setting
.
The
unit
resets
at
90
%
of
the
minimum
closing
value
.
Time
Setting
The
setting
of
the
time
dial
determines
the
length
of
time
the
unit
requires
to
close
its
contacts
when
the
current
reaches
a
predetermined
value
.
The
contacts
are
just
closed
when
the
dial
is
set
on
0
.
When
the
dial
is
set
on
10
,
the
disk
must
travel
the
maximum
amount
to
close
the
contacts
;
therefore
this
setting
gives
the
maximum
time
setting
.
The
primary
adjustment
for
the
time
of
operation
of
the
unit
is
made
by
means
of
the
time
dial
.
However
,
further
adjustment
is
obtained
by
moving
the
permanent
magnet
along
its
supporting
shelf
;
moving
the
magnet
toward
the
disk
shaft
decreases
the
time
,
while
moving
it
away
increases
the
time
.
Pickup
Test
Use
rated
frequency
for
both
the
pickup
and
time
tests
.
Set
the
relay
at
the
0.5
time
-
dial
position
and
2.0
ampere
tap
.
Using
the
test
connections
in
Figure
9
,
the
main
unit
should
close
its
contacts
within
±
2.0
%
11
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