GE IAC60T User manual

IN
ST RU
CT
ION S
GEK-65573
TIME
OVERCURRENT
RELAYS
IAC6OT,
IAC8OT,
IAC9OT
GENERAL
ELECTRIC

GEK-65573
CONTENTS
PAGE
DESCRIPTION
3
APPLICATION
3
CONSTRUCTION
4
RATINGS
5
TIME
OVERCURRENT
UNIT
5
INSTANTANEOUS
OVERCURRENT
UNIT
7
AUXILIARY
UNIT
8
CONTACTS
P
BURDENS
8
TIME
OVERCURRENT
UNIT
8
INSTANTANEOUS
OVERCURRENT
UNIT
9
AUXILIARY
UNIT
9
CHARACTERISTICS
10
TIME OVERCURRENT
UNIT
10
INSTANTANEOUS
OVERCURRENT
UNIT
10
RECEIVING, HANDLING
AND
STORAGE
10
ACCEPTANCE
TESTS
11
VISUAL INSPECTION
11
MECHANICAL INSPECTION
11
TIME
OVERCURRENT
UNIT
11
INSTANTANEOUS
OVERCURRENT
UNIT
11
CAUTION
11
DRAWOUT
RELAY
TESTING
11
POWER
REQUIREMENTS
GENERAL
12
TIME
OVERCURRENT
UNIT
12
TIME
SETTING
12
PICKUP
TEST
13
TIME
TEST 13
INSTANTANEOUS
UNiT
13
PICKUP
AND
RESET
13
AUXILIARY
UNIT
13
INSTALLATION
14
INSTALLATION
TESTS
14
TIME
OVERCURRENT UNIT
14
INSTANTANEOUS
UNIT
14
AUXILIARY
UNIT 14
PERIODIC
CHECKS
AND
ROUTINE MAINTENANCE
15
TIME OVERCURRENT
UNIT
15
INSTANTANEOUS
UNIT
15
AUXILIARY UNIT
15
CONTACT CLEANING
15
SYSTEM TEST
15
SERVICING
16
MECHANICAL
ADJUSTMENTS 16
TIME
OVERCURRENT
UNIT
16
INSTANTANEOUS
UNIT
16
ELECTRICAL
ADJUSTMENTS
17
TIME OVERCURRENT
UNIT
17
INSTANTANEOUS
UNIT
17
RENEWAL
PARTS
18
LIST
OF FIGURES
19
2

GEK—65573
TIME
OVERCLJRRENT
RELAYS
IAC6OT, IAC8OT,
IAC9OT
DESCR
IPTION
The
IAC0T,
IAC8OT
and
IAC9OT
relays
consist
of
two
induction
disk
timer
overcurrent
units
with
wound
shading
coils
for
torque
control,
two
plunger-type
instantaneous
overcurrent
units
and one
dc
auxiliary
unit,
all
mounted in
the
L2
size
drawout
case.
The
three
models
differ
only
in
the
characteristic
of
the
time
overcurrent
unit,
which
is
inverse
in
the
IAC6OT,
very
inverse
in
the
IAC8OT
and
extremely
inverse
in
the
IAC9OT.
The
relays
do not
include
a
tarciet
seal-in
unit
since
this
feature
is provided
by the
associated
distance
relays.
The
time
overcurrent
units
are
adjustable
over
a
range
of
8
to
1;
the
instantaneous
units
have
an
adjustment
range
of
25
to
1.
The
available
ranges
in
amperes
of
both
the
time
and
instantaneous
units,
as well
as information
on
their
continuous
and
short
time
ratings,
are
provided
in
the
section
on RATINGS.
The
outline
and
mounting
dimensions
of
the
L2
size
drawout
case
are
shown
in
Fig.
15.
APPI
ICAT
ION
The
IAC6OT,
I1C80T
and
IAC9OT
relays
are
specifically
designed
for
use in
conjunction
with
two
zones
of
step—distance
relays.
In this
application
the
contacts
of
the
instantaneous
overcurrent
units
are
connected
to
supervise
the
first
zone
distance
relay
trip
circuit
to
prevent
incorrect
tripping
on
loss
of
the
ac
potential
supply.
The
time
overcurrent
units
are
torque
controlled
by means
of
wound
shading
coils
and
contacts
of
the
dc
auxiliary
unit.
The
second
zone
distance
relays
operate
the
auxiliary unit,
which
in
turn
completes
the
wound
shading
coil
circuit.
Subsequent
operation
of
the
time
overcurrent
units
provides
the
second
zone
time-delay
tripping.
This
arrangement
provides
the
means
for
obtaining
close
coordination
between
second
zone tripping
and
overcurrent
relays
or
fuses
installed
at tapped loads
on
the
line.
At
the
same
time
the
scheme
provides
a
definite
second
zone
reach
for
the
overall
line
protection
and
backup.
The
elementary
diagram
in
Fig.
10 illustrates
how
any one
of
the
three
IAC
relays
covered
by
this
instruction
book
may
be
used
in
conjunction
with
the
CEV51A
and
CEY52A
mho-type
distance
relays
to
provide
two—zone
protection
against
multi—phase
faults.
The
CEY51A
is
a
first-zone
directional
mho
relay
that
trips
without
time
delay
through
contacts
of
the
instantaneous
units
of
the
IAC
relay.
The
CEY52A
is
the
second
zone
directional
mho
relay
that
operates
the
dc
auxiliary
unit
in
the
JAC
relay
to
torque
control
the
time
overcurrent
unit.
The
time
overcurrent
unit
trips
the breaker via
the
CEY52A
contacts.
These
ntructiuns
do
not
purport
to
cover
all
details
or
variations
in
equipment
nor
to
provide
for
cvii-y
pcesibZ
contingency
to
be
met
n
cnneetion
with
installation,
operation
or
,rintenance.
Should
turthe
information
b
desi red or
houid
partJ
cular
problerro
arise
which
arm
not
covered
sufficiently
for
the
our
chaser’s
purposos, the
mat
ter ullauirt
be
referred
to
the
General
Tiectric
Company.
•
T
the
xtcnt
required
the urnjucts
descrl,ed
herein
r,ieet
applicable
aSsr.
1555
and
NEM4
standards;
hat
no
such
rssuranee
is
g;
yen
C;
th
respet
to
lonol
codes
and
ordinances
because they
vary
greatly.
3

GEK-65573
It
is
important to
note
that
the
instantaneous
overcurrent
units
in
the
IAC
relays
are
not
designed for
continuous operation
in the picked-up
position. For
this
reason
these
units
must
he
set
above
the
maximum
expected
full
load
current.
However, if
the
contacts
of
these
units
are
to
he
connected to supervise the
first
zone
CEY51A
contacts,
it
is obvious
that
they
must
operate
reliably
on
the
minimum
internal
line
fault
current.
The
range
and
characteristics
of
the
time
overcurrent
units
must
he selected
to
accomodate
the
desired
pickup
setting
and
at
the
same
time
permit
time
coordination
with
fuses
and
relays
at
other
points
on
the
system.
The
scheme
shown
in
Fig.
10 provides
protection against
multi—phase
faults.
Separate
ground
relays
must
be
used
for
protection against
single-phase-to—ground
faults.
CONSTRUCTION
The
inverse and
very
inverse
time
overcurrent units
consist
of a
tapped
current
operating coil
wound
on
a U—magnet
iron
structure. The
several
taps
on
the
operating
coil
are
connected
to
tap
points
on
a tap
block
to provide a ready
means
of selecting
the
pickup
point. The
U-magnet
includes
wound
shadinci
coils
which
are
connected
to
a
contact
of
the
auxiliary
unit
“A.”
The
extremely inverse
time
overcurrent
unit
is
the
watt-metric
type.
The
upper
portion
of
the
iron
structure
has
two
concentric
windings on
the middle
leg
of
the
magnetic
circuit.
One
of
these
is
a tapped
operating
current
winding
connected to
tap
points
on
a
tap
block.
The
other
is
a
floating
winding which
is connected
in
series
with
a
resistor
(and
capacitor
on the
extremely
inverse
units)
and
the
two
coils
on
the
lower
legs
of
the
magnetic circuit.
This
floating
circuit
is
connected
to
a
contact
of
the
auxiliary
unit
hA.H
In
both
types
of
time
overcurrent
units
the
disk
and
shaft
assembly
carry
the
moving
contact
which
completes
the
trip
circuit
when
it
touches
the stationary
contact.
The
shaft
is
restrained by a
spiral
spring
to
give
the
proper
contact closing
current
depending
on tap
setting, and
its
motion
is retarded
by
an
Plnico
drag macnet,
which
acts
on
the
disk
to
produce
the
desired
time
characteristic.
The
lower
bearing
for
the
shaft
assembly
consists
of
a
polished
pin
driven
into
the
shaft
and
riding
on a
sapphire
jewel,
spring
mounted
in
a screw-type
assembly.
The
upper
bearing
consists
of
an adjustable
pivot
assembly
mounted on
the
frame
and
having
a
polished
pin
which
projects
into
a
bronze guide
ring
located
at the
top
of
the
shaft.
The
variable
retarding
force
resulting
from
the
gradient of
the spiral
spring
is
compensated
by
the
spiral
shape
of
the
induction
disk.
This
results
in
an increased
driving force as
the
spring
winds
up.
A calibrated
time
dial
determines the
distance
of
travel
of the
moving
contact,
thus
controlling
the
pickup
time.
Each
of
the
instantaneous
overcurrent
units
is of
the
plunger-type
construction.
The
adjustable
armature
is
mounted
on the
threaded
portion
of a
plunger
rod
which
carries
the
moving
contacts
upward
as
the
armature is
operated.
The
armature
is
drawn
upward
into
the
coil
by
the
flux created
in
the
rectangular
magnet
frame
and
a
cylindrical
pole
piece
inside
the
coil.
Guides
for
the
plunger
rod are
provided
at the
4

GEK—65573
top
by
a
hole
in
the pole
piece,
and at
the bottom
by the fit
of
the
molded
contact
carrier
inside
the
calibration
Lube.
Openings
in
the
sides
of
the
calibration
tube
allow
access
to
the
armature
to
adjust
pickup.
The
auxiliary
unit
‘A”
is
a
telephone—type
relay.
The
construction
of
a
typical
telephone-type
relay
is shown
in
Fig.
11.
The
components
of
each
relay
are
mounted
on
a
cradle
assembly
which
can
be
easily
removed from
the
relay
case.
The
cradle
is
locked
in
the
case
by
means
of
latches
at
the
top
and
bottom.
The
electrical
connections
between
the
case
blocks
and
cradle
blocks
are
completed
through
removable
connection
plugs.
Separate
testing
plugs
can
be
inserted
in
place
of
the
connection
plugs
to permit
testing
the
relay
in its
case.
The
cover
is
attached
to
the
case
from
the front
and
includes
an
interlock
arm
which
prevents
the
cover
from
being
replaced
until
the
connection
plug
has been
inserted.
RATINGS
TIME
OVERCURRENT
UNIT
Ratings
of
the
time
overcurrent
unit
are
given
in
Table
I.
TABLE
I
PICKUP
RANGE, AMPERES
FREQUENCY
MAIN
(TIME)
INSTANTANEOUS
RELAY
CYCLES
UNIT
UNIT
0.5
-
4.0
IAC6OT
60
2.0
-
16.0
________
J
2—50
IAC8OT
0.5
-
4.0
60
IAC9OT
1.5
-
12.0
Available
taps
for
time
overcurrent
units
are
shown
on
Table
LI
TABLE
II
RANGE
AMPERES
TAPS
AVAILABLE
(AMPERES)
0.5
-
4.0
0.5,
0.6, 0.7, 0.8,
1.0,
1.?,
1.5, 2.0, 2.5, 3.0,
4.0
1.5
—
12
1.5,
2.0,
2.5, 3.0,
4.0,
5.0,
6.0, 7.0,
8.0,
10.0,
12.0
2.0 -
16
2.0,
2.5,
3.0, 4.0,
5.0,
6.0, 7.0,
8.0,
10.0,
12.0,
16.0
5

SEK-65573
The
one—second
thermal
ratinqs
are
listed
in
Table
III
TABLE
III
RELAY
RANGE
ONE-SECOND
MODEL
(AMPS)
RATING
(AMPS)
IAC6OT
0.5
-
4
70
2
- 16
260
0.5
- 4
140
IAC8OT
1.5-12
260
0.5
- 4
125
IAC9OT
1.5
- 12
260
For
ratings
of
less
than
one
second,
the
rating
may
be calculated
according
to
the formula
I
=./i,
where
T
is
the
time
in
seconds
that
the
current
flows. T
The continuous
ratings
for
the
various
taps
of each
model and
current
range
are
given
in
Tables
IV,
V and
VI.
CONTINUOUS
0.5
-
4.0
AMP RANGE
TABLE
IV
RATING
OF
0.5
- 4.0
AMP TOC
UNITS
MODEL
TAP
0.5 0.6
0.7
0.8
1.0
1.2
1.5
2.0
2.5
3.01
4.0
IAC6OT 1.6
1.8
2.0
2.1
2.3 2.7
3.0
3.5
4.0
4.5
5.0
IAC8OT
4.0
4.5 5.5
5.5 6.0 7.0
7.5
9.0
10.0
11.0
13.0
IAC9OT
3.5
3.7
4.0
4.5 5.0 5.5
6.0
7.0
8.0
9.0
10.0
6

GEK—65573
TABLE
V
CONTINUOUS
RATING
OF
1.5-
12.0
AMP
TOC
UNITS
1.5
-1?.O
AMU
RANGE
MODEL
TAP
1.5
2.0
2.5
3.0
4.0 5.0
6.0
7.0
8.0
10.0
12.0
IACBOT
RATING
10.0
11.5
13.0
14.5 17.0
19.0
21.0
23.0
23.5
27.5
30.5
(AMPS)
IAC9OT
9.5
10.5
11.5
12.5
14.0
15.5
17.0 18.0 19.0
20.0
20.0
TABLE
VI
CONTINUOUS
RATING
OF 2
-
16.0
AMP
TOC
UNITS
2
-
16.0
AMP
RANGE
MODEL
TAP
2.0 2.5
3.0
4.0
5.0 6.0
7.0
8.0
10.0
12.0
16.0
RATING
IAC60(AMps)
8.0
9.0
10.0
12.0 14.0 15.0 16.0
17.5
20.0 20.0
20.O
INSTANTANEOUS
OVERCURRENT
UNIT
These
coils
are
suitable
for
dc
and
frequencies
from
25
to
60
hertz.
The
coils
are
rated
for
five
amperes
continuous
and
have
a
one-second
rating
of
260
amperes.
The
instantaneous
unit
has
a range
of
2
to
50 amperes.
Tap
settings
are
made
per
Table
VII
TABLE
VII
Topof
Relay
LINK POSITIONS
2
12.5
12.5
Pickup
3.?
8
20
Amperes
5
12.5
31.3
(Calibration
8
20
50
Marks)
j__________________________
7

GEK-65573
AUXILIARY
UNIT
The
auxiliary
unit
“A”
has
a
dual
dc
voltaqe
rating of
48/125
volts.
CONTACTS
The
contacts
of
both
the
time
overcurrent
and
instantaneous
units
will
close and
carry
30
amperes
dc
momentarily
for
tripping
duty
at
control voltages
of
250 V dc
or
less.
The
breaker
trip
coil
circuit
should,
however,
always
be
opened
by
a
circuit
breaker
auxiliary
switch
or
other
suitable
means. If
the
tripping
current
exceeds
30
amperes,
an
auxiliary
tripping
relay
should
be
used.
B
(JR
DENS
TIME
OVERCURRENT
UNIT
Burdens
for
the
inverse
time
overcurrent
unit
(IAC6OT)
are
given in
Table
VIII.
TABLE
VIII
BURDENS
AT
MIN.
BURDENS IN
VA
AT
5
AMPS
PICKUP MIN.
TAP
OHMS
(7) CALCULATED
FROM
3
10 20
IMPEDANCE
AT
MIN. TIMES TIMES TIMES
MINIMUM
PICKUP
RANGE
HZ
TAP
R
Z
PICKUP PICKUP
PICKUP
(127)
0.5-
4.0
60 0.5
5.60
21.0 22.0
10.80
5.00
3.66
550.0
.O-16.O
60
2.0
0.37
1.44 1.45
0.65
0.32 0.24
36.3
NOTE:
The
impedance
values given
are
those for
the
minimum
tap
of
each
relay.
The
impedance
for
other
taps
at
pickup
current
(tap
rating)
varies inversely
(approximately)
as
the square
of
the
tap
rating.
For
example,
for
a
relay
with
0.5-4.0
amp
range,
the
impedance
of
the
0.5
ohm
tap is
given
as
22.0
ohms. The
impedance
of
the
2.0 amp
tap
at
2.0
amperes
is
(0.5/2)2
x
22
=
1.37
ohms.
Burdens
for
the
very
inverse
time overcurrent
unit
(IAC8OT)
are
given
in
Table IX.
TABLE
IX
BURDENS
AT
MIN.
BURDENS
IN
VA
AT
5
AMPS
PICKUP_MIN.
TAP
OHMS
(7) CALCULATED
FROM
3
10
20
IMPEDANCE
AT
MIN.
TIMES
TIMES TIMES
MINIMUM
PICKUP
RANGE
HZ
TAP R
7 PICKUP PICKUP
PICKUP
(12Z)
0.5- 4.0
60
0.5
1.40
3.90
4.15
4.20
2.90
2.20
104.0
1.5—12.0
60
1.5
0.23
0.53 0.58
0.58
0.36
O.?8
14.5
8

____
The
impedance
values
given
are
those
for the
minimum
tap
of
each
relay.
The
impedance
for
other taps
at
pickup
current
(tap
rating)
varies
inversely
(approximately)
as
the square
of
the
tap
rating.
For
example,
for
a
relay
with
0.5-4.0
amp
ranqe,
the
impedance
of
the
0.5
ohm
tap
is
given
as
4.15
ohms.
The
rnpedance
of
the
2.0
amp
tap
at 2.0
amperes
is
(0.5/2)2
x
4.15
0.26
ohm.
Burdens
for
the
extremely
inverse
time
overcurrent
unit
(IAC9OT)
are
given
in
Table
X.
TABLE
X
BURDENS
AT
MIN.
BURDENS
IN
VA
AT
5
AMPS
PICKUP
MIN.
TAP
OHMS
(Z)
CALCULATED
FROM
3
10
20
IMPEDANCE
AT
M1N.
TIMES
TIMES
TIMES
MINIMUM
PICKUP
RANGE
HZ
TAP
R
Z PICKUP
PICKUP
PICKUP
(1 2 Z)
0.5-
4.0
60
0.5
0.80
1.38
1.60
1.60
1.60
1.60
40
1.5-12.0
60
1.5
0.085
0.147
0.17
0.17
0.17 0.17 4.25
The
impedance
values
given
are those
for
the
minimum
tap of
each
relay.
The
impedance
for
other
taps
at
pickup
current
(tap
rating)
varies
inversely
(approximately)
as the
square
of
the tap
rating.
For
example,
for
a
relay
with
0.5-4.0
amp range,
the
impedance
of
the
0.5 ohm
tap
is
given
as
1.60
ohms.
The
impedance
of
the
2.0 amp
tap
at
2.0 amperes
is
(0.5/2)2
x
1.60
=
0.10 ohm.
The
auxiliary
unit
milliamperes
at
48
VDC.
a
battery
drain
of
35.7
coil has
a
resistance
of
2500
ohms
and
a
battery
drain
of
1.92
A
1000 ohm
series
resistor
is
added
for
125 VDC
operation
with
milliamperes.
GEK—65573
NOTE:
NOTE:
INSTANTANEOUS
OVERCURRENT
UNIT
Burdens
for
the
instantaneous overcurrent
unit
are
given
in
Table
IX.
TABLE
XI
AUXILIARY
UNIT
9

GEK-65573
CHARACTERISTICS
TIME
OVERCURRENT
UNIT
Pickup
of
the
time
overcurrent
unit
is
defined
as
the
current
required
to
close
the
contacts
from
the
0.5
time-dial
position.
The
pickup
value
is
within
three
percent
of
tap
value.
The
setting
of the
time
dial
determines the
length
of
time
the
unit requires
to
close
its
contacts
when
the
current
reaches the
predetermined
value.
The
contacts
are
just
closed
when
the
dial
is
set
at
zero.
When
the dial
is
set
at
10, the
disk
must
travel
the
maximum
distance
to
close
the
contacts;
this
gives
the
maximum
time
setting.
The
percentage
of
the
minimum
closing
value
of
current
that
the
unit
will
reset
is:
IAC6OT
-
90
percent
IAC8OT
-
80
percent
IAC9OT
-
85
percent
The
time
to
reset
to
the Number
10
time-dial
position,
when
the
current
is
reduced
to
zero,
is
approximately:
IAC6OT
-
7
seconds
IAC8OT
-
60
seconds
IAC9OT
-
57
seconds
The
time-current
characteristics
are
shown
in
Fig.
6,
7 and
8 for
the
IAC6OT,
IAC8OT
and
IAC9OT,
respectively.
INSTANTANEOUS
OVERCURRENT
UNIT
The
instantaneous
overcurrent
unit is
continuously
adjustable
over
a
25:1
range.
Pickup
is
set
by adjusting
the
vertical
position
of
the
armature
relative
to
the
markings
on
the
calibration
tube.
The
instantaneous
unit
will
reset
to
the
de—
energized
position
between
85 and
95 percent
of its
pickup
setting.
RECEIVING,
HANDLING
AND
STORAGE
These
relays,
when
not
included
as
part
of a
control
panel
will
be
shipped
in
cartons
designed
to
protect
them
against
damage.
Immediately
upon
receipt
of
a
relay,
examine
it
for
any
damage
sustained
in transit.
If injury
or
damage
resulting
from
rough
handling
is evident,
file
a
damage
claim
at
once
with
the
transportation
company
and
promptly
notify
the
nearest
General
Electric
Apparatus
Sales
Office.
Reasonable
care
should
be
exercised
in
unpacking
the
relay
in order
that
none
of
the
parts
are
injured
or the adjustments
disturbed.
If the
relays
are
not
to
be
installed
immediately,
they
should
be
stored
in their
original
cartons
in
a
place
that
is
free
from
moisture,
dust
and
metallic
chips.
Foreign
matter
collected
on
the
outside
of the
case
may
find
its
way
inside
when
the
cover
is
removed,
and
cause
trouble
in
the
operation
of
the
relay.
10