GE IBCG51M User manual

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INSTRUCTIONS
6EK-498sm
Supersedes
GEK-49822
GROUND DIRECTIONAL OVERCURRENT RELAYS
TYPES
IBCG51M
IBC4';;Hi;UA
IBCG53M
IBCG53M(-)YlA
IBCG54M
IBCG77M
IBCG78M
-
.T.
‘i:.:
.I
GENERAL
ELECTRIC

GEK-49822
_.
_.
I
CONTENTS
f
DESCRIPTION
.......................
3
APPLICATION
......................
4
..
RATINGS
..........................
5
TIME OVERCURRENT UNIT
....
':.
.... 6
DIRECTIONAL UNIT
...............
7
INSTANTANEOUS UNIT
.............
7
TARGET AND SEAL-IN UNIT
........
8
CONTACTS
.......................
8
CHARACTERISTICS
..................
8
PICKUP .........................
RESET (TIME OVERCURRENT UNIT)
...
i
OPERATING TIME
.................
BURDENS
........................
z
CONSTRUCTION
.....................
ll
DIRECTIONAL UNIT
...............
ll
CONTACTS
........................
11
TIME OVERCURRENT UNIT
...........
11
TARGET SEAL-IN UNIT
.............
12
INSTANTANEOUS UNIT
.............
12
RECEIVIN6.
HANDLING AND
STiitAiE
:
...
..I..
................
12
ACCEPTANCE TESTS
.................
13
VISUAL INSPECTION
..............
13
MECHANICAL INSPECTION
..........
13
TOP UNIT (TOC)
...............
13
BOTTOM UNIT (DIR)
............
13
TARGET AND SEAL-IN UNIT/
INSTANTANEOUS UNIT
..........
13
DRAWOUT
RELAYS, GENERAL
........ 14
POWER REQUIREMENTS, GENERAL
....
14
TARGET AND SEAL-IN UNIT
........ 14
PICKUP AND DROPOUT TEST
...... 14
TIME OVERCURRENT UNIT
..........
15
CURRENT SETTING
..............
15
TIME SETTING
.................
16
PICKUP TEST
..................
16
TIME TEST ....................
16
PAGE
DIRECTIONAL UNIT
............
17
CURRENT POLARIZATION
...... 17
POTENTIAL POLARIZATION
....
17
.....
.-
INSTANTANEOUS UNIT
..........
17
INSTALLATION
..................
LOCATION
....................
::
MOUNTING
.....................
17
CONNECTIONS
.................
INSPECTION ..................
g
CAUTION ...................
OPERATION
.....................
;;
TARGET AND SEAL-IN UNIT
.....
18
TIME OVERCURRENT UNIT
.......
18
DIRECTIONAL UNIT
............
19
CURRENT POLARIZATION
.......
19
POTENTIAL POLARIZATION
.... 19
INSTANTANEOUS UNIT
..........
19
P;:;ER;;CKS
AND
ROUTINE
..................
TARGET AND SEAL-IN UNIT
.....
:;
TIME OVERCURRENT UNIT
.......
19
DIRECTIONAL UNIT
............
19
INSTANTANEOUS UNIT
SERVICING
...............................
:;
TARGET AND SEAL-IN UNIT
.....
20
TIME OVERCURRENT UNIT
.......
20
DISK AND BEARINGS
......... 20
CONTACT ADJUSTMENT
........ 20
CHARACTERISTICS CHECK
AND ADJUSTMENTS
..........
20
DIRECTIONAL UNIT
............
21
BEARINGS ..................
21
CUP AND
STATOR
............
21
CONTACT ADJUSTMENTS
.......
21
BIAS TORQUE ADJUSTMENT
.... 22
CLUTCH ADJUSTMENT
.........
22
INSTANTANEOUS UNIT
..........
23
CONTACT CLEANING
..........
23
RENEYAL
PARTS
. . . . . . . . . . . . . . . .
23
2

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EK-49822
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GROUND DIRECTIONAL OVERCURRENT RELAYS
IBCGSlM
IBCG53M IBCG77M
IBCGSlH(-)YlA
IBCG53M(-)YlA
IBCG78M
IBCG52M IBCG54M
DESCRIPTION
The Type
IBCG
relays are ground directional overcurrent relays used primarily for
the protection of feeders and transmission lines. They are available with either
inverse, very inverse or extremely inverse time characteristics.
All the
IBCG
relays contain a time overcurrent unit of the induction disk type and
an instantaneous directional unit of the induction cup type. The-directional unit can
be potential polarized, or current polarized, or both, and it directionally controls
the operation of the time overcurrent unit.
A'target seal-in unit is provided in each of the relays. The operating coil for
this unit is connected in series with the contacts of the time overcurrent unit so that
it will pick up whenever the time overcurrent unit operates. The contacts of the
seal-
in unit are connected in parallel with the contacts of the time overcurrent unit to
provide protection for them and their associated control springs.
(I
Those relays having the designation
YlA
following the model number also contain a
Hi-Seismic instantaneous overcurrent unit of the hinged armature construction.
*
The
IBCG52M,
54M and the 78M relay models are the two contact versions of the
IBCG51M,
53M and the 77M relay models respectively.
All the
IBCG
relays are mounted in standard
Ml
size
drawout
cases; the outline and
l
panel drilling dimensions for which
are
given in Fig.
26. Internal
connections for the
relays are given in Fig. 5, 6, 7, 8 and 9. Typical external connections-are shown by
Fig.
10, 11
and 12.
Table
1
lists the various models and ranges that are available.
*Indicates Revision
3
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L
TA8LE
1
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EXTENDED RANGE
IBCG
RELAYS
(
Relay Time
Inst
Pickup Range
Int
Bode1
Characteristic
Unit
Inst.
Time
Conn.
IBCG51'(
)A
-
18CG52;(-)A
Inverse
N
Inverse
Ni
0542-16
0:5:4:
2-16
F'
5
F:;:
25
IBCG51M(-)YlA
Inverse Yes
6-150
0.5-4, 2-16
Fig. 6
IBCG53M(-)A
Very
Inverse No
-
Fig. 5
IBCG541uI(-)A
Very
Inverse
No
Fig. 7
IBCG53M(-)YlA
Very Inverse
Yes
Fig. 6
IBCG77M(-)A
Extremely Inverse
No
-
0.5-4, 1.5-12
Fig.
8
IBCG78M(-)A
Extremely
Inverse No
-
0.5-4,
1.5-12
Fig. 26
:
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APPLICATION
The Type
IBCG
relays are ground directional overcurrent relays that may be used as
ground fault detectors in a transmission line protective relaying scheme.
The relays contain a time overcurrent unit that is torque controlled by an
instantaneous directional overcurrent unit.
The directional unit may be polarized from
a source of potential, or current, or both sources may be used to dual polarize the
unit.
It is advantageous to use dual polarization because changing system conditions
may cause current polarization to be favored at some times whereas voltage polarization
1
* might be favored at others.
Fig. 13 illustrates the effect of using dual polarization
as compared to polarization from a source of voltage or current alone.
The differences between the various models covered by this instruction book are shown
in Table I.
Inverse
time relays should be used on systems where the fault current
flowing through a given relay is influenced largely by the system generating capacity
at the time of the fault.
Very inverse time and extremely inverse time relays should be
used in cases where the fault current magnitude is dependent mainly upon the location
of the fault in relation to the relay, and only slightly or not at all upon the system
generating setup. The reason for this is that relays must be set to be selective with
maximum fault current flowing. For fault currents below this value, the operating time
becomes greater as the current is decreased. If there is a wide range in generating
capacity, together with variation in short-circuit-current with fault position, the
operating time with minimum fault current may
be
exceedingly long with very inverse
time relays and even longer with extremely inverse time relays. For such cases, the
inverse time relay is more applicable.
The operating time of the time overcurrent unit for any given value of current and
tap setting is determined by the time dial setting. The operating time is inversely
* proportional to the current magnitude as illustrated by the time curves in Figs.
15,
16
and 17. Note that the current values on these curves are given as multiples of the tap
setting.
That is, for a given time dial setting, the time will be the same for 80
amperes on the eight ampere tap as for 50 amperes on the five ampere tap, since in both
cases, the current is ten times setting.
(
*Indicates Revision
4

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WC-49822
If
selective action of two or more relays is required, determine the maximum possible
short-circuit
current of the line and then choose a time value for each relay that
'
differs sufficiently to insure the proper sequence in the operation of the several
circuit breakers. Allowance must be made for the time involved in opening each breaker
after the relay contacts close.
The
YlA
relays contain a Hi-Seismic instantaneous overcurrent unit. This unit may be
set high to trip directly for faults
scme
distance down the transmission line.
In
determining the setting for this unit, itwill
be necessary to consider faults directly
behind the relay as well as at the remote terminal because the unit is non-directional.
The unit should be set with a suitable amount of margin above the maximum external
* fault current.
The effects of transient overreach, as illustrated in Fig. 19, should
also be taken into account in determining the setting.
RATINGS
The IBCG relays described in this
instructio
,I
are available in"50 and
60
hertz
models.
The TOC (time overcurrent) units have extended (8-to-l) range similar to the
800 series
IAC
relays. The
IOC
(instantaneous overcurrent) units, when used (see Table
I),
have extended
(25-to-l)
range.
Ratings of the operating current circuits of the
TOC, IOC and the directional units are shown individually.
However, since all
operating current circuits are normally connected in series, the
operating.coil
ratings
of all units should be considered in determining the rating of the entire operating
circuit.
Relay
Model
IBCG51M
IBCG51M(-)YlA
IBCG52M
IBCG53M
IBCG53M(-)YlA
IBCG54M
IBCG77M
IBCG78M
TABLE 2
ONE SECOND RATING OF TOC UNITS
Range
(Amps)
0.5-4-o
2.0-16
0.5-4.0
1.5-12
0.5-4-o
1.5-12
.!
One Second
Rating (Amps)
70
260
140
260
125
260
*Indicates Revision
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TIME,
OVERCURRENT
UNIT
f
The one second ratings of the TOC units are given In Table 2. The
continuous
ratlngs
for the
vartous
taps of each model and current range are glven in Tables 3. 4 and 5.
*
TABLE 3
CONTINUOUS
RATING OF 0.5-4.0 AMP TOC UNITS
.-. m
p Range
Model
Tap
0.5
0.6
0.7 0.8
1.0
1.2 1.5 2.0
2.5
3.0 4.0
IBCG51M
IBCGSlM(-)YlA Rating
1.6
1.8
2.0 2.1
2.3 2.7 3.0 3.5 4.0 4.5
5.0
IBCG52M
(Amps)
IBCG53M
IBCG53M(-)YlA
4.0 4.5 5.5 5.56.07.0 7.5 9.010.0 11.0 13.0
IBCG54M
IBCG78M
3.5 3.7 4.0 4.5 5.05.5 6.0 7.08.0 9.010.0
*
TABLE 4
CONTINUOUS RATING OF 1.5-12.0 AMP TOC UNITS
1.5-12.0 Amp
Ranqe
Model Tap
1.5 2.0 2.5 3.0 4.0 510 6.0 7.0 8.0
10.0 12.0
IBCG53M
IBCG53M(-)YlA Rating
10.0 11.5 13.0 14.5 17.0 19.0 21.0 23.0 23.5 27.5 30.5
IBCG54M
(Amps)
IBCG77M
IBCG78M
9.5 10.5
11.5 12.5 14.0 15.5 17.0 18.0 19.0 20.0 20.0
*Indicates Revision
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TABLE 5
(-
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
IBCGSlM
Rating
;;;;;;;t-'YlA' 8.0
9.0 10.0 12.0 14.0 15.0 16.0 17.5 20.0 20.0 20.0
(Amps)
IBCG77M
IBCG78M
9.5 10.5 11.5 12.5 14.0 15.5 17.0 18.0 19.0 20.0 20.0
DIRECTIONAL UNIT
The directional unit current polarizing and operating coils have a continuous
rating of five amperes and a one second rating of 150 amperes.
The potential polarizing coils will withstand 120 volts continuously and 360
volts for 60 seconds.
INSTANTANEOUS UNIT
The instantaneous unit coil is of the hinged armature construction and is
tapped for operation on either one of two ranges (H or L). Selection of the high or
low range is determined by the position of leads
T
and E at terminal 6. See Table 6
and the applicable internal connections referenced in Table 1. For the H range,
connect lead T to terminal 6 and lead E to the auxiliary terminal that is mounted
On
terminal 6.
For range L, reverse leads T and E.
TABLE 6
CONTINUOUS
AN
D
ONE
SECONDRATINGS
OF
rot
UN
IT
One
** Continuous Second
Instantaneous Range Rating Rating
Unit (Amps)
Range (Amps)
(Amps)
(Amps
1
6-150
L 6-30
10.2
260
H
30
-
150 19.6
*
The range is approximate, which means that
6-30,
30-150 may be 6-29,
28-150.
There will always be at least one ampere overlap between
the maximum L setting and the minimum H setting. Whenever possible,
always select the higher range, since it has the higher continuous
rntino.
*Indicates Revision
7

GEK-49822
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TARGET
AND SEAL
-
IN UN
IT
f
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The rating
and impedance of the seal-in unit for the 0.2 and 2 ampere taps are given
in Table 7.
The tap setting used will depend on the current drawn by the
trlp
~011.
The 0.2 ampere tap is for use with trip coils which operate on currents ranging
frcm
0.2 up to 2.0 amperes, at the minimum control voltage. If this tap is used with trip
coils requiring more than two amperes, there is a possibility that the resistance of
seven ohms will reduce the current to so low a value that the breaker will not be
tripped.
The two ampere tap should be used with trip coils that take two amperes or more at
minimum control voltage, provided the current does not exceed 30 amperes at the maximum
control voltage. If the tripping current exceeds 30 amperes, the connections should
be
arranged so that the induction unit contacts will operate an auxiliary relay,
which
in
turn energizes the trip coil or coils. On such an application, it may be necessary to
connect a loading resistor in parallel with the auxiliary relay coil to allow enough
current to operate the target seal-in unit.
CONTACTS
The current-closing rating of the induction unit is 30 amperes for voltages not
exceeding 250 volts. Their current-carrying rating is limited by the tap rating of the
seal-in unit.
*TABLE 7
SEAL-IN UNIT RATINGS
0.2 2.0
DC RESISTANCE
+lD%
(OHMS)
8.3
0.24
MIN OPERATING (AMPERES) +0-25%
0.2 2.0
CARRY CONT. (AMPERES) 0.37
2.3
CARRY 30 AMPS
FOR
(SEC.)
0.05 2.2
CARRY 10 AMPS FOR (SEC.) 0.45
20
60 Hz IMPEDANCE (OHMS)
50.0 0.65
PICKUP
When potential polarized, the directional unit will pick up at 3.6 volts-amperes
at the maximum torque angle of
60
degrees lag (current lags voltage). When current
polarized, it will pick up at approximately 0.5 ampere with the operating and
polarizing coils connected in series.
The performance of the unit with
simultan-
l
eous
current and potential polarization is typified in Fig. 13.
*Indicates Revision
8

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The current required to close the time overcurrent unit contacts will be within five
fZX\..
percent of the tap screw setting.
RESET (TIME OVERCURRENT UNIT)
Inverse
time overcurrent units reset at
90
percent of the minimum pickup current,
very inverse time units at 80 percent,
and extremely inverse time units at 85 percent.
When the relay is de-energized, the time required for the disk to
canpletely
reset
to the number ID time dial position is approximately six seconds for inverse time
relays,
and 60 seconds for very inverse time and
extremely
inverse time relays.
OPERATING TIME
:_
.:./
*The time curve for the directional unit is shown in Fig. 14.
*
The time curves of the time overcurrent unit are shown in Figs. 15, 16 and 17,
respectively for inverse, very inverse and extremely inverse time relays. For the same
operating conditions, the relay will operate repeatedly within one or two percent of
the same time.
The time-current characteristic of the Hi-Seismic instantaneous unit is shown by
l
Fig. 18 and its transient overreach characteristic is shown by Fig.
19.
BURDENS
c
The capacitive burden of the potential polarizing circuit of the directional unit at
60 cycles and 120 volts is ten volt amperes at 0.86 power factor. Table 8 gives the
current circuit burdens of the directional unit.
TABLE 8
DIRECTIONAL UNIT CURRENT
CIRCUIT
BURDEN AT 60 CYLES AND 5 AMPERES
Circuit
Z (Ohms)
Operating 0.46
VA
12.0
P.F
0.52
Watts
6.24
Polarizing 0.24 6.0 0.95
5.27
Table 9 gives the current circuit burdens of time overcurrent units.
Ordinarily the potential circuit is in the open corner of broken delta potential
transformers and the current circuits are in
the residual circuits of current
transformers.
The burden is, therefore, only imposed for the duration of the ground
fault and need be considered only for this brief period. Table 10 gives the burden of
the instantaneous unit.
i
*Indicates
Revision
9

GEK-49922
TABLE 9
CURRENT
CIRCUIT
BURDENS AT 60 CYCLES OF THE TDC UNIT
Tap
Burdens at Minimum Pickup
Ohms
Impedance at
HA
Time
Range Eff. Res. React.
**Imped
+Volt
3 Times 10 Times At Five
Characteristic
(Amps) (Ohms) (Ohms) (Ohms) Amps P.F. Min P.U. Min P.U. Amperes
Inverse
0.5/4
5.60
21.0 22.0 5.5
0.25
10.80 5.00
555.0
Inverse 2/16
0.37
1.44
1.49
5.8 0.25 0.65 0.32 36.3
;
Very
Inverse
0.5/4 1.40 3.90 4.15
1.0 0.33 4.20 2.90 104.0
Very
Inverse
1.5/12
0.23
0.53 0.58 1.3
0.40
0.58 0.36 14.5
Extr. Inverse
0.5/4
0.80
1.38
1.60
0.4 0.50
1.60 1.60
40.0
Extr.
Inverse
1.5/12
0.005 0.147 0.17
0.4 0.50
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 current rating. Example: for
the Type
IBCGSlM
relay,
0.5/4
amperes the impedance of the 0.5 ampere tap
is 22 ohms.
The im
edance
of the one ampere tap, at one ampere, is
approximately
(0.5/l)!
x 22 = 5.5 ohms.
+ Some companies list relay burdens only as the volt-ampere input to
operate at minimum pickup. This column is included so a direct comparison
can be made.
It
should not be used in calculating volt-ampere burdens in a
CT secondary circuit, since the burden at five amperes is used for this
purpose.
+
Calculated from burden at minimum pickup.
TABLE 10
BURDEN OF THE INSTANTANEOUS UNIT
Inst
Min .
Burden at Min
Burden Ohms
(Z)
Unit Range Pickup
Pickup
(Ohms1
Times Pickup
Amps
Hz
Range Amps
Amps R
JX
Z
3
10
20
6-150
60
ii
6-30
6 0.110 0.078 0.135 0.095
0.081
0.079
30-150
30 0.022 0.005 0.023 0.022 0.022 0.222
*Indicates Revision
10

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CONSTRUCTION
::::
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The IBCG relays consist of two units, a time overcurrent unit (top) of the
induction disk type, and an instantaneous power directional unit (bottom) of the
induction cup type.
The directional unit is either potential or current polarized or
both and, by means of its closing contacts, directionally controls the operation of the
time overcurrent unit.
The IBCG relays have a target seal-in unit
dnd
models with the
YlA
suffix, as
shown by Table 1, have a hinged armature type instantaneous overcurrent unit.
The IBCG relays are mounted in the single-ended Ml
drawout
case.
DIRECTIONAL UNIT
.
:
The directional unit is of the induction-cylinder construction with a laminated
stator
having eight poles projecting inward and arranged symmetrically around a
stationary central core.
The
cuplike
aluminum induction rotor is free to operate in
the annular air gap between the poles and the core.
The poles are fitted with
current-
operating, current polarizing and potential polarizing coils.
The principle by which torque is developed is the same as that of an induction
disk relay with a wattmetric element, although, in arrangement of parts, the unit is
more like a split-phase induction motor. The induction-cylinder construction provides
higher torque and lower rotor inertia than the induction-disk construction resulting in
a faster and more sensitive unit.
c
CONTACTS
The directional unit contacts which control the time overcurrent unit are shown in
*
Fig.20.
They are of the low gradient type, specially constructed to minimize the
effects of vibration. Both the stationary and moving contact brushes are made of low
gradient material which,
when subjected to vibration, tend to follow one another,
hence, they resist contact separation.
The contact dial (A) supports the stationary contact brush (8) on which is mounted
a conical contact tip (C).
The moving contact arm (D) supports the moving contact
brush
(E)
on which is mounted a button contact tip (F). The end of the moving contact
brush bears against the inner face of the moving contact brush retainer
(G).
Similarly, the end of the stationary contact brush bears against the inner face of the
stationary contact brush retainer (H).
The stop screw (J), mounted on the contact
dial, functions to stop the motion of the contact arm by striking the moving contact
brush retainer after the moving and stationary contact members have made contact. The
stationary contact support (K) and the contact dial are assembled together by means of
a mounting screw (L) and two locknuts (M).
TIME OVERCURRENT UNIT
The inverse time and very inverse time overcurrent units consist of a tapped
current operating coil wound on a U-magnet iron structure. The tapped operating coil
is connected to taps on the tap block.
The U-magnet contains wound shading coils which
are connected in series with'a directional unit contact. When power flow is in such a
direction as to close the directional unit contacts, the shading coils act to produce a
split-phase field which, in turn, develops torque on the operating disk.
*Indicates Revision
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The'extremely inverse time overcurrent unit is of the wattmetric type similar to
that used in
watthour
meters except as follows: the upper portion of the lron
structure has two concentric windings on the middle leg of the magnetic circuit.
One
of these is a tapped current winding connected to taps on the tap block; the other
iS
a
floating winding which is connected in series with the directional unit. contacts, a
resistor, a capacitor and the two coils on the lower legs of the magnetic circuit.
When
power flow is in such a direction as to close a directional unit contact, the unit
develops torque on the operating disk.
The disk shaft carries the moving contact which completes the trip circuit when it
touches the stationary contact or contacts.
The shaft is restrained by a spiral spring
to give the proper contact-closing current, and its motion is retarded by a permanent
magnet acting on the disk to produce the desired time characteristic.
The variable
retarding force resulting from the gradient of the spiral spring is compensated by the
spiral shape of the induction disk, which results in an increased driving force as the
spring winds up.
TARGET SEAL-IN UNIT
A seal-in unit is mounted on the left side of the time overcurrent unit. This unit
has its coil in series and its contacts in parallel with the main contacts of the
overcurrent unit, arranged in such a manner that when the main contacts close, the
seal-in unit picks up and seals-in around the main contacts.
When the seal-in unit
operates,
it raises a target into view which latches up and remains exposed until
manually released by pressing the button located at the lower left corner of the cover.
INSTANTANEOUS UNIT
The IOC unit is a small hinged armature type instantaneous element and is mounted on
the right side of the TOC unit. The IDC element operates over a
25-to-one
total range
obtained by using a tapped coil which provides a five-to-one low range and a
five-to-
one high range; this combination provides the
25-to-one
total range. When the current
reaches a predetermined value, the instantaneous element operates closing its
COntaCt
circuit and raising its target into view.
The target latches in the exposed position
until it is released.
The same button that releases the target seal-in unit
alSO
releases the target of the instantaneous unit.
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
imnediately,
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.
t:
12

i
\.
:.::
.:
.:.
::.
*
I/
t.
Imnediately
upon receipt of the relay an INSPECTION AND ACCEPTANCE TEST should be
made to ensure that no damage has been sustained in shipment and that the relay
calibrations have not been disturbed. If the examination or the test indicates that
readjustment is necessary, refer to the section on SERVICING.
These tests may be performed as part of the installation or
acceptance
tests
at
the discretion of the user.
Since most operating caapanies use different procedures for acceptance and
installation tests, the following section includes all applicable tests that may be
performed on these relays.
VISUAL INSPECTION
Check the
nmaeplate
stamping to ensure that the model number and rating of the
relay agree with the requisition.
Remove the relay
frmn
its case and check that there are no broken or
cr;;Xk&
molded parts or other signs of physical damage and that all screws are tight-
that the shorting bars are in the proper location(s) as shown by the internal connec-
tions
diagrmas,
Figs. 5 to 9, inclusive, and that the main brush is properly formed
t0
contact the shorting bar.
MECHANICAL INSPECTION
Top Unit (TOC)
1.
The disk shaft end play should be
O.D05-0.015
inch.
2.
The disk should be centered in the air gaps of both the electromagnet and drag
magnet.
3.
Both air gaps should be free of foreign matter.
4.
The disk should rotate freely and should return by itself to the reset position.
5.
The moving contact should just touch the stationary contact when the time dial
iS
at the zero time dial position.
Bottom
Unit (DIR)
::
The rotating shaft end play should be 0.015-0.020 inch.
The contact gap should be 0.015-0.025 inch on the low gradient contact.
Tarqet and Seal-in Unit/Instantaneous Unit
::
The armature and contacts should move freely when operated by hand.
80th
contacts should make at approximately the same time.
3.
The target should latch into view just as the contacts make
and should unlatch
when the target release button is operated.
4.
The contacts
shou1.d
have approximately 0.030 inch wipe.
*Indicates Revision
ACCEPTANCE TESTS
13

:_
:.
:...
GEK-49822
DRAWOUT'RELAYS.
GENERAL
Since all
drawout
relays in service operate in their cases, it is recommended that
they be tested In their cases or an equivalent steel case. In this way, any
ma_gnetic
effects of the enclosure will be accurately duplicated during testing. A relay may be
tested without removing it from the panel by using a
12XLA13A
test plug. This plug
makes connections only with the relay and does not disturb any shorting bars in the
case. The
12XLA12A
test plug may also be used. Although this test plug allows greater
testing flexibility, it requires CT shorting jumpers and the exercise of greater care,
since connections are made to both the relay and the external circuitry.
POWER REQUIREMENTS, GENERAL
All alternating current operated devices are affected by frequency. Since
non-
sinusoidal waveforms can be analyzed as a fundamental frequency plus harmonics of the
fundamental frequency, it follows that alternating current devices (relays) will be
affected by the applied waveform.
Therefore, in order to properly test alternating current relays, it
iS
essential
to
use a
sine
wave of current and/or voltage.
The purity of the
sine
wave
(i.e.,
its
freedun
from harmonics) cannot be expressed as a finite number for any particular
relay; however, any relay using tuned circuits,
R-L or RC networks, or saturating
electromagnets (such as time overcurrent relays) is affected by non-sinusoidal
waveforms.
TARGET AND SEAL-IN UNIT
I
The target and seal-in unit has an operating coil tapped at 0.2 and 2.0 amperes.
When used with trip coils operating on currents ranging from 0.2 to 2.0 amperes at
the minimum control voltage, the target and seal-in tap screw should be set in the 0.2
ampere tap.
When the trip coil current ranges from two to 30 amperes at the minimum
control voltage, the tap screw should be placed in the 2.0 ampere tap.
The seal-in tap screw is the screw holding the right-hand stationary contact of the
seal-in unit. To change the tap setting, first remove the connecting plug. Then take a
screw
from
the left-hand stationary contact and place it in the desired tap.
Next,
remove the screw
from
the other
tap*and
place it back in the left-hand contact. This
procedure is necessary to prevent the right-hand stationary contact from getting out of
adjustment.
Tap screws should
never
be left in both taps at the same time.
Pickup and Dropout Test
1. Connect relay studs 1 and 2 (see internal connections diagram) to a DC source,
ammeter and load box so that the current can be controlled over a range of 0.1 to 2.0
amperes.
2. Close or jumper the contact(s) that parallel the seal-in unit contact.
3. Increase the current slowly until the seal-in unit picks up. See Table 11.
4. Open the parallel contact circuit of step 2; the seal-in unit should remain in the
picked up position.
5. Decrease the current
slow&
until the seal-in unit drops out. See Table 11.
14
-

,.
,.
GEK-49822
TABLE
11
TARGET AND SEAL-IN UNIT OPERATING CURRENTS
PICKUP
DROPOUT
TAP
CURRENT CURRENT
0.2
0.115
-
0.195
0.05 OR MORE
2.0
1.15
-
1.95
0.55 OR MORE
TIME OVERCURRENT UNIT
Rotate the time dial slowly and check by means of a lamp that the contacts just close
at the zero time dial setting.
Where 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 setting, there should be sufficient gap
between the stationary contact brush and its metal backing strip to ensure
approximately
l/32
inch wipe.
Current Setting
(
The minimum current at which time overcurrent unit will close its contacts
is
determined by the position of the plug in the tap block. The tap plate on this block is
marked in amperes, as shown in Tables 3, 4 and 5.
When the tap setting is changed with the relay energized in its case, the following
procedure must be followed: (1) Remove the connecting plug; this de-energizes the
relay and shorts the current transformer secondary winding. (2) Remove the tap screw
and place it in the tap marked for the desired pickup current.
(3) Replace the
connecting plug.
::_.
The minimum current required to rotate the disk slowly and to close
the
contacts
should be within five percent of the value marked on the tap plate for any tap setting
and time dial position.
If
this adjustment has been disturbed, it can be restored by
means of the spring adjusting ring.
The ring can be turned by inserting a screw driver
blade in the notches around the edge. By turning the ring, the operating current of the
unit can be brought into agreement with the tap setting employed. This adjustment also
permits any desired setting to be obtained intermediately between the available tap
settings.
Pickup adjustment by means of the control spring applies to the
IBCGW52
and
IBCG53/54
relays. A different procedure applies to the
IBCG77/78
relays. For the
IBCG77/78
relays, the pickup of the unit for any current tap setting is adjusted by
means of the variable resistor in the phase-shifting circuit. This adjustment also
permits
any
desired setting intermediately between the various tap settings to be
obtained.
The control spring is prewound approximately 660 degrees with the contacts
just closed.
Further adjustment of this setting is
seldan
required; if it is required,
15

;
,'
GEK-49822
:j
2:.
..:.
because of the insufficient range of the variable resistor, it should
necessary to wind up the control spring adjuster more than 30 degrees (one
unwind it more than 90 degrees (three notches) from the factory
Setting.
never be
notch) or
4
Test connections for making pickup and time checks on the time over-current unit are
shown in Fig. 22 and 23.
Use a source of
120
volts or greater with good wave form and
constant frequency.
Stepdown
transformers or phantom loads should not be employed in
testing induction relays since their use may cause a distorted wave form. The contact
in the wound shading coil circuit marked D, see internal connection diagram, must be
blocked closed or
jumpered
for both the pickup test and the time test.
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 and 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. Be sure the magnet never extends out beyond
the cutout in the disk.
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
connection in Fig. 22, the main unit should close its contacts within
22.0
percent
Of
tap value current
(1.96-2.04
amps).
Time Test
Set the relay at No. 5 time dial setting and the 2.0 amp tap. Using the test
connection in Fig. 23, apply five times tap current (10.0 amp) to the relay. The relay
should operate within the limits given in Table 12.
TABLE 12
TOC UNIT OPERATING TIME
LIMITS
Time in Seconds
Relay Type
Min.
Midpoint Max
IBCG51-IBCG52
1.72 1.78 1.83
IBCG53-IBCG54
1.27 1.31 1.35
IBCG77-IBCG78
:’
0.890.92 0.95
*Indicates Revision
16

'c..'.DIREC;IONAL
UNIT
Current Polarization
6EK-49822
l
a. Connect per Fig. 24 of TEST CONNECTIONS.
:
b;The
unitshould close its contacts within.five percent of 0.5 ampere. The clutch
-.~
I
..should
slip between 8-18 amperes.
CAUTION: This level of current can overheat the
coil if applied too frequently or for too long a period of time.
Potential Polarization
a. Connect per Fig. 25 of TEST CONNECTIONS.
b..With V set for five volts at terminals 9 to
10,
the unit should close its contacts
between
0.75-1.75
amps.
INSTANTANEOUS UNIT
Make sure that the instantaneous unit is in the correct range in which it is to
operate. See the internal connections diagram and Table 6.
Whenever possible,
use
the higher range since the higher range has a higher
continuous rating.
The instantaneous unit has an adjustable core located at the top of the unit. T
O
set
the instantaneous unit to a desired pickup, loosen the locknut and adjust the core.
Turning the core clockwise decreases the pickup, turning the core counterclockwise
increases the pickup.
Bring up the current slowly until the unit picks up. It may be
necessary to repeat this operation,
until the desired pickup value is obtained. Once
the desired pickup value is reached, tighten the locknut.
CAUTION:
Refer to Table 6 for the continuous and one second ratings of the
instantaneous unit.
Do not exceed these ratings when applying current to
the instantaneous unit.
The range of the instantaneous unit (see Table 6) must be obtained between a core
position of
l/8
of a turn of full clockwise, and
20
turns counterclockwise from
the
full clockwise position.
INSTALLATION
The location should be clean and dry, free
fran
dust and excessive vibration and
well lighted to facilitate inspection and testing.
MOUNTING
The relay should be mounted on a vertical surface.
The outline and panel drilling
diagram is shown in Fig. 26.
*Indicates Revision
17

GEK-49822
CONNECTIONS
f
l
The internal connection diagrams for the various relays are shown in Fig. 5 to
9.
Typical external wiring diagrams are shown by Fig. 10, 11 and 12.
Unless mounted on a steel panel which adequately grounds the relay case, it is
recommended that the case be grounded through a mounting stud or screw with a conductor
not less than
#12
B&S gage copper wire or its equivalent.
*
INSPECTION
At the time of installation, the relay should be inspected for tarnished contacts,
loose screws, or other imperfections. If any trouble is found, it should be corrected
in the manner described in the section on SERVICING.
CAUTION
Every circuit in the
drawout
case has an auxiliary brush.
It is especially
important on current circuits and other circuits with shorting bars that the auxiliary
brush be
bent
high enough to engage the connecting plug or test plug before the main
brushes do. This will prevent CT secondary circuits from being opened. Refer to
*
Fig. 21.
OPERATION
Before the relay is put into service,
it should be given a check to determine that
I
factory adjustments have not been disturbed. The time dial will be set at zero before
the relay leaves the factory.
If the setting has not been changed,
itwill
be
necess;;;
to change this setting in order to open the time overcurrent unit contacts.
following tests are suggested:
TARGET AND SEAL-IN UNIT
1.
Make sure that the tap screw is in the desired tap.
2.
Perform pickup and dropout tests as outlined in the
TIME OVERCURRENT UNIT
ACCEPTANCE TEST section.
*
1.
Set tap screw on desired tap. Using the test circuit in Fig. 22, apply
approximately twice tap value current until the contacts just close. Reduce the
current until the light in series with the contacts begins to flicker. This value
of current should be within five percent of tap value.
2.
Check the operating time at some multiple of tap value. This multiple of tap
value may be five times tap rating or the maximum fault current for which the
relay must coordinate. The value used is left to the discretion of the user. Use
*the test circuit shown in Fig. 23.
*Indicates Revision
18

.
.
c..
DIRECTIONAL
UWIT
:.:.:
:
-:.
i..:.
Current Polarization
.
*
a. Connect
per.Fig.
24 of TEST CONNECTIONS.
b. Adjust the control spring for 0.5
amperes
pickup if current polarized or dual
polarized.
Potential Polarization
l
c. If potential polarized, connect-per Fig. 25 of
d;-Adjust
the control spring for 3.6 volt
maperes
T
amperes are
recoaaaended
values for this test.
INSTANTANEOUS UNIT
TEST CONNECTIONS.
(
210
percent). Ten volts and 0.36
1. Select the desired range by making the proper connections at the rear of the relay
(see internal connections diagram).
Whenever possible always select the higher
range since it has a higher continuous rating.
2. Set the instantaneous unit to pick up at the desired' current level.
See the
ACCEPTANCE TEST section.
PERIODIC CHECKS AID ROUTINE MAINTENANCE
(
In view of the vital
role'of
protective relays in the operation of a power system,
it is important that a
periodic:test
progrma
be followed. It is recognized that the
interval between periodic checks will vary depending upon environment, type of relay
and the user's experience with periodic testing. Until the user has
accm'aulated
enough
experience to select the test interval best suited to his individual requirements,-it
is suggested that the points listed below be checked at an interval of
fran
one to
two
years.
These tests are intended to ensure that the relays
original settings.
If deviations are encountered, the
serviced as described in this manual.
TARGET AND SEAL-IN UNIT
Check that the unit picks up at the values shown in
::
Check that the unit drops out at 25 percent or more
TIME OVERCURRENT UNIT
have not deviated
fran
their
relay must be retested and
Table 11.
of tap value.
1.
Perform pickup test as described in the INSTALLATION section for the tap in
service.
2.
Perform the time tests as described in the INSTALLATION section.
DIRECTIONAL UNIT
.:_:
Repeat the portion of the installation test for the polarity condition for which
:;;:,
G,
the relay is connected in service.
*Indicates Revision
19

GEK-49822
:._
:-
INSTANTANEOUS UNIT
i:
Check that the instantaneous unit picks up at the desired current level, as outlined
in the ACCEPTANCE TESTS and the INSTALLATION TEST sections.
SERVICING
These relays are adjusted at the factory and it is advisable not to disturb the
adjustments.
If, for any reason, they have been disturbed or it is found during
installation or periodic testing that the relay is out of limits, the-checks and
adjustments outlined in the following paragraphs should be observed.
It
is
suggested
that this work be done in the laboratory.
TARGET AN0 SEAL-IN UNIT
Repeat the visual and mechanical inspections and the pickup and dropout current
checks as outlined in the ACCEPTANCE TESTS section.
TIME OVERCURRENT UNIT
Disk and Bearings
The jewel should be turned up until the disk is centered in the air gaps, after
which it should be locked in this position by the set screw provided for this purpose.
The upper bearing pin should next be adjusted so that the disk shaft has
about1/64
inch
(
end play.
Contact Adjustment
The contacts should have about
l/32
inch wipe.
That is, the stationary contact
tip should be deflected about
l/32
inch when the disk completes its travel. Wipe
iS
adjusted by turning the wipe adjustment screw thereby adjusting the position of the
brush relative to the brush stop.
When the time dial is moved to the position where it holds the contacts just
closed, it should indicate zero on the time-dial scale. If it does not and the brushes
are correctly adjusted, shift the dial by changing the position of the arm attached
to
the shaft just below the time dial.
Loosen the screw clamping the arm to the shaft and
turn the arm relative to the shaft until the contacts just make for zero time-dial
setting.
Characteristics Check and Adjustments
Repeat the portions of the ACCEPTANCE TESTS section that apply to the time
overcurrent unit.
Also, check reset voltage and time as outlined under RESET in the
CHARACTERISTICS section; low reset voltages or long reset times may indicate excessive
friction caused by a worn bearing or by mechanical interference.
:’
*Indicates Revision
20
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