GE STD15C - PERIODIC TESTS; PICKUP CHECK; HARMONIC RESTRAINT CHECK

GEK—45
307
in
effect
a
superfine
file.
The
polishing
action
is
so
delicate
that
no
scratches
are left,
yet
corroded
material
will
be
removed
rapidly
and
thoroughly.
The
flexibility
of
the
tool
insures
the
cleaning
of
the
actual
points
of
contact.
Fine
silver
contacts
should
not
he
cleaned
with knives,
files,
or
abrasive
paper
or
cloth.
Knives
or
files
may
leave
scratches,
which
increase
arcing
and
deterioration
of the
contacts.
Abrasive
paper
or
cloth
may
leave
minute
particles
of
insulating
abrasive
material
in
the
contacts,
and
thus
prevent
closing.
The
burnishing
tool described
above
can
be obtained
from
the
factory.
PERIODIC
TESTS
An
operation
test
and
inspection
of the
relay
and its
connections
should
be
made at
least once
every
six
months.
Tests
may
be
performed
as
described
under
INSTALLATION
TESTS,
or
if
desired
they
may
be
made
on
the
service
taps
as
described
in
this
sec
tion.
When
inserting
or
withdrawing
a
test
plug with
U—shaped
through
jumpers
to
complete
the
trip
circuit
through
the
test
plug,
similar
through
jumpers
should
also
be
used
on
studs
8
and
9
to
maintain
the
connections
from
the relay
to
the
case.
If
this
is
not
done,
there
is
a
risk
of
false
tripping
upon
inserting
or
withdrawing
the
plug.
PICKUP
The
method
for
checking
pickup
is
as described
under
the
heading
INSTALLATION
TESTS
except,
of
course,
pickup
current
will
be
different
depending
upon
the
winding
(WDG)
1
service
tap.
Pickup
may
be
determined
as
follows:
I
=
0.30
x
WDG
I
Tap
Of
course,
when checking
pickup
on
a
particular
service
tap,
the
L±
10%
expected
variation
still
applies,
the
acceptable—as—found
range
being
=
9.0 x
0.30
x
WDG
1
Tap
to
1.10
x
0.30
x
WDG
1
Tap
Example
WDG1
Tap
=
3.5A
Ii
=
0.90
x
0.30
x
3.5 to
1.10
x
0.30
x
3.5
=
0.94
to
1.16
amperes
HARMONIC
CURRENT
RESTRAINT
The procedure
for
checking
harmonic
restraint
is
as
described
under
the heading
INSTALLATION
TESTS,
except
that
the test
current
values
must
be
modified
as
follows:
12
(DC)
=
0.80
x
WDC
I
Tap
Ii
=
0.90
x
WDG
1
Tap
to
1.10
x
WDG
1
Tap
In
the event
a
suitable
DC
meter
is
not
available,
12
(AC)
2.25
x
12
(DC).
(Theoretically,
this
conversion
factor
would
be
2.22
if
the
rectifier
back
resistance
were
infinite.)