GE MicroVersaTrip AKR-75 User manual

•
GEK-64460A Maintenance Manual
Low Voltage
Power CircuitBreakers
Types AKR-75/100 and AKS-50
AKR-60-75
AKR-90-100
AKS-5A-50
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Low-Voltage Power Circuit Breakers
Table of Contents
Description Page
SECTION 1-lntroduction ...................... 4
1.1
1.2
Inspection and Maintenance .................... 4
Renewal Parts
........... , .................... 4
SECTION 2-General Description ............ 6
2.1 Frame Size ................................... 6
2.2 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.3 Mounting ..................................... 7
2.4 Trip Device ................................... 7
2.5 Short Circuit Ratings ........................... 7
SECTION 3-Storage, Safety and
Maintenance
.................... 9
3.1 Storage ...................................... 9
3.2 Safety ....................................... 9
3.3 Maintenance .................................. 9
SECTION 4-Breaker Operation ............. 10
4.1 Manual Closing .............................. 10
4.2 Electrical Closing ............................. 10
4.2.1 Alternate Control Circuit ....................... 11
4.3 Connections ................................. 12
4.3.1 Stationary Breaker ............................ 12
4.3.2 Drawout Breaker ............................. 12
4.4 Tripping ..................................... 13
4.5 Charging and Closing Using
the Maintenance Handle
....................... 13
SECTION 5-Contact Maintenance ......... 14
5.1 Slow Closing the Breaker ...................... 14
5.1.1 Electrical Breaker ............................. 14
5.1.2 Manual Breaker .............................. 14
5.2 Arc Quencher Removal and Inspection ........... 15
5.2.1 Removal and Replacement ..................... 15
5.3 Separation of Front and Back Frames ............ 16
5.4 Back Frame Assembly ......................... 18
5.5 Measuring Contact Force ...................... 19
5.5.1 Stationary Arcing Contacts .................... 19
5.5.2 Stationary Main and Intermediate Contacts ....... 19
5.6 Measuring Contact Wipe ....................... 19
5.7 Adjusting Contact Wipe ....................... 19
5.8 Measuring Contact Open Gap .................. 21
5.9 Checking Contact Sequence ................... 22
5.10 Replacement of Contacts ...................... 22
5.10.1 Stationary Arcing Contacts .................... 22
5.10.2 Movable Arcing Contacts ...................... 22
5.10.3 Movable Main and Intermediate Contacts ........ 23
5.10.4 Stationary Intermediate and Main Contacts ....... 24
5.11 Assembly and Adjustment of Crossbar ........... 25
© 1993 GENERAL ELECTRIC COMPANY
2
Description Page
SECTION 6-Breaker Maintenance ......... 26
6.1 Safety Precautions ........................... 26
6.2 Lubrication .................................. 26
6.3 Breaker Mechanism Adjustments ............... 26
6.3.1 Trip Latch ................................... 26
6.3.2 Latch Buffer ................................. 26
6.3.3 Reset Latch Bearing and Prop .................. 26
6.4 Electrical Mechanism ......................... 28
6.4.1 Control Components .......................... 28
6.4.2 Charging Motor .............................. 29
6.4.3 Motor Operator Unit ........................... 30
6.4.4 Spring Discharge Interlock ..................... 32
6.5 Manual Mechanism ........................... 32
6.5.1 Mechanism Part Replacement .................. 33
6.5.2 Ratchet Pawl Replacement ..................... 35
6.5.3 Adjustments ................................. 35
6.6 Drawout Mechanism .......................... 36
6.7 Drawout Mechanism Lock ...................... 36
SECTION 7-Accessories .................... 37
7 .1 Primary Disconnects .......................... 37
7.1.1 AKA 75/100 .................................. 37
7 .1.2 AKS/AKST 50 ................................ 38
7.2 Secondary Disconnects ....................... 39
7.2.1 Replacement ................................ 39
7.3 Auxiliary Switch .............................. 40
7.3.1 Replacement ................................ 40
7.3.2 Adjustments ................................ 40
7.4 Shunt Trip ................................... 41
7.4.1 Replacement ................................ 41
7.4.2 Adjustment .................................. 41
7.5 Undervoltage Device .......................... 42
7.5.1 Replacement ................................ 42
7.5.2 Adjustment .................................. 42
7.6 Static Time-Delay Undervoltage ................. 43
7.7 Electric Lockout Device ........................ 44
7.7.1 Adjustment .................................. 44
7.8 Bell Alarm Device ............................. 45
7 .8.1 Adjustment .................................. 45
7.9 Open Fuse Lockout Device ..................... 46
7.9.1 Coll Replacement ............................. 46
7.9.2 Adjustments ................................. 46
SECTION 8- Type SST Overcurrent
T' D .
np
ev1ce ...................... 47
8.1 Programmer Unit ............................. 47
8.2 Current Sensors .............................. 48
8.2.1 Replacement of Current Sensors
-AKS
50 ..................................... 50
8.2.2 Replacement of Current Sensors
-AKA 75/100
................................. 51
8.3 Flux Shift Trip Device .......................... 51
8.4 Troubleshooting .............................. 54
8.4.1 SST Test Set ................................. 54
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Insert to document GEK-64459D and GEK-64460A
Breaker operation
This is an insert to the maintenance manuals for
AKR 30/50 (GEK 64459D) and AKR 75/100
(GEK64460A). The insert describes the operation
of the
breaker with the newly introduced electronic closing
system.
For the
AKR 30/50 insert to section 5 starting on
page 11.
For the AKR 75/100 insert to section 4 starting on
page
10
Replacement Parts
Replacement printed circuit board assembly for 48
VDC applications: #10060126G1
Replacement printed circuit board assembly for all
other voltage applications: #10060126G2
(X)
(+)
(Y)
(-)
TC
FIG.E1 -ELEMENTARY DIAGRAM FOR
ELECTRICALLY OPERATED
DRAWOUT BREAKER.
CONTACT POSITIONS ARE SHOWN WITH BREAKER
OPEN AND CLOSING SPRINGS DISCHARGED. TYP #
183L712 & # 568B736 "E" SERIES
2110197
E.2 ELECTRICAL CLOSING
On electrically operated breakers the closing
springs are charged
by a gear motor. With the springs
discharged, voltage applied to the control circuit will
energize the motor through the "G" switch contacts -see
Fig. E1. The motor, through the gear reduction output
crank, compresses the closing spring until they are fully
charged. As this fully charged position is reached,
mechanically operated switches "F" and "G" reverse their
shown position, the "G" switch deenergizing the motor
and the "F" switch establishing a circuit to the One-Shot
electronic.
With the closing spring propped fully-charged, the
breaker
is ready for closing. This may be accomplished
electrically by depressing the closing switch "PB" on the
breaker (if so equipped) or by a remote closing switch.
Operation
of the closing switch energizes the One-Shot
electronic, witch
in turn energizes the closing solenoid
"CC". This removes the prop, releasing the closing
springs to close the breaker.
As the One-Shot electronic
is energized through a
closing contact, the "X" relay
is energized as well. The
"X" relay will latch
in and therefore prevent a second
closing operation on the breaker
in the event it is tripped
open automatically. The closing signal must be released
and reapplied before a second closing operation can
occur.
The closing springs on the electrically operated breakers
can be manually charged.
cc
F
G
L
M
PB
x
OS
LEGEND
CLOSING SOLENOID
CUTOFF SWITCH,
CLOSED WHEN
CLOSING SPRING IS FULLY
CHARGED.
CUTOFF SWITCH. OPEN WHEN
CLOSING SPRING IS FULLY
CHARGED.
AUXILIARY SWITCH
CHARGING MOTOR
CLOSE PUSH-BUTTON ON BREAKER
ESCUTCHEON, OPTIONAL.
CONTROL RELAY
ONE-SHOT ELECTRONIC. PULSES
THE CLOSING SOLENOID FOR
250 MSEC.
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FIG. 13 -MANUAL OPERATION OF CLOSING SOLENOID
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Table of Contents
Description Page
8.4.2 Resistance Values ................... , ........ 55
8.4.3 False Tripping -Breakers
Equipped
with Ground Fault .................... 55
8.5 SST Cabling Diagrams ......................... 55
SECTION 9- Type ECS
Overcurrent
Trip Device
...................... 58
9.1 ECS Cabling Diagram ........................ 59
SECTION 10-MicroVersaTrip ™
10.1
10.1.1
10.1.2
10.2
10.2.1
10.2.2
10.3
10.3.1
10.3.2
10.4
10.5
10.5.1
10.5.2
10.6
Overcurrent
Trip Device
..................... 60
Programmer Unit ..................... , ....... 60
Fault Trip Indicators .......................... 60
Remote Fault Indication ................... , ... 60
MicroVersaTrip
™Installation .................. 62
AKS 50 Installation ........................... 62
AKR 50/100 Installation ........................ 63
Current Sensors
.............................. 64
Replacement of Current Sensors
· AKS
50 ..................................... 65
Replacement
of Curent Sensors
· AKR
751100 ................................. 65
Flux Shift Trip Device .......................... 65
Troubleshooting .............................. 65
Resistance Values
............................ 66
False Tripping-Breakers
Equipped With Ground Fault
................... 67
MicroVersaTrip TM Cabling Diagrams . . . . . . . . . . . . 67
SECTION 11-RMS-9/Epic
MicroVersaTrip® ............... 11
11.1 Programmer Unit .............................. 71
11.1.1 Fault Trip Indicators ............................ 71
11.2 RMS-9 & Epic MicroVersaTrip Installation .......... 71
11.3 Current Sensors ............................ · ... 72
11.3 .1 Replacement of Current Sensors ................. 75
11.4 Flux Shifter Trip Device ......................... 75
11.5 Troubleshooting ............................... 75
11.5.1 Resistance Values ............................. 75
11.5.2 False Tripping-Breakers Equipped
With Ground Fault
... , ......................... 76
11.6 Cabling Diagrams ............................. 76
SECTION 12-MicroVersaTrip™ Plus and
MicroVersaTrip PMTrip Units ... 79
12.1 Trip Unit ..................................... 79
12.2 Read This First ................................ 80
12.3 Product Structure ............................. 80
12.4 Trip Unit Removal and Replacement .............. 81
12.5 Phase Current Sensors ............... , ......... 82
12.6 Neutral Current Sensors .......................... 83
12.7 RatingPlug Removal and Replacement .. , ......... 83
12.8 Trip Unit Functions .............. , ............. 83
12.9 Trouble-Shooting Guide .......... , ............. 84
Description Page
SECTION
13-Type EC
Overcurrent
13.1
13.1.1
13.1.2
13.1.3
13.1.4
13.2
13.3
13.4
13.4.1
13.4.2
13.4.3
13.5
13.5.1
13.5.2
13.5.3
13.5.4
13.6
13.7
13.7.1
13.7.2
13.8
13.9
Trip Device ..................... 85
Direct Acting Tripping Device EC-1 B ............. 87
Long Time Delay Tripping ...................... 87
Short Time Delay Tripping ............. , ........ 87
Instantaneous Tripping -High Set ......... , ..... 87
instantaneousTripping -Low Set ................ 87
Replacement ................. , . . . . . . . . . . . . . . 87
Adjustments ........................ , ........ 88
Series Overcurrent Tripping
Device EC·2A
... , ...... , .. , . . . . . . . . . . . . . . . . . . 89
Long Time-Delay and High Set
Instantaneous Tripping
........................ 89°
Instantaneous Low Set Tripping ................ 89
Instantaneous High Set Tripping ................ 89
Serles Overcurrent Tripping Device EC-1 .......... 91
Short Time-Delay Tripping ..................... 91
Long Time-Delay Tripping ...................... 91
Instantaneous Tripping ........................ 92
EC-1 Adjustment ............................. 92
Positive Trip Adjustment ....................... 92
Reverse Current Tripping Device ................ 93
Adjustments ................................. 94
Replacements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
Switchette Feature ... , ....................... 94
Trip Device Replacement ...................... 94
SECTION 14-Electrical Characteristics ... 95
Table 23
Charging and Closing Operating Currents ................. 95
Table 24
Beil Alarm Contact-Rating .............................. 95
Table 25
Auxiliary Switch Contact Sequence ...................... 95
Table 26
Auxiliary Switch Contact Ratings ........................ 95
Table 27
Charging Times ....................................... 95
Table 28
Shunt Trip and Undervoltage Device ...................... 96
Table
29
Coil Resistance ....................................... 96
Table 30
Instantaneous Undervoltage Device Settings
................ 97
Table 31
Time-Delay Undervoltage Device Settings .................. 97
THESE INSTRUCTIONS ARE INTENDED FOR USE BY QUALIFIED
PERSONNEL
FOR INSTRUCT/ON AND MAINTENANCE PURPOSES.
REPRODUCTION IN WHOLE OR IN PART JS NOT PERMITTED
WITHOUT
THE EXPRESS PERMISSION OF GENERAL ELECTRIC.
3
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SECTION 1-1 ntroduction
Introduction
These instructions provide the maintenance procedures
and describe the operation of the 1600 thru 4000 amp AC,
6000
amp DC frame size type AKA, AKS low voltage power
circuit breakers listed in Table 1 and Table 2.
The proper use, care and maintenance of these breakers is
a
prime safety consideration for the protection of
personnel, as well as a means of minimizing equipment
damage when faults occur. Persons who apply, use, and
service these breakers will
acquire the knowledge they
need by gaining the information contained in these
instructions.
1.1-lnspection and Maintenance
Breakers should be cared for under a systematic
maintenance program. Taking each breaker out of service
periodically for inspection and maintenance is an excellent
means of establishing high service reliability. It is good
policy to have one or more spare breakers to install in
place of breakers requiring maintenance. Keeping a stock
of recommended renewal parts will insure that
maintenance work can be done quickly.
How frequently an individual breaker should be inspected
will depend on the circumstances of its use. It would be
well
to inspect any breaker at least once a year. If it is
frequently operated, or installed in an area of high
humidity or a dusty, dirty atmosphere, inspections should
be more often. Inspections might be monthly under
adverse conditions.
Table 1-AKS 50 Designations
A basic maintenance inspection should consist of an
overall visual check,
plus observation of a few closing and
opening operations. If a breaker is seldom operated such
that it remains open or closed for a period of six months or
more, it is recommended that arrangements be made to
open and close it several times in succession.
Dirt, grease or other foreign material on any parts of the
breaker should be removed by a thorough and careful
cleaning. Insulating surfaces should be checked for
conditions that could degrade insulating properties.
During an inspection, the breaker's contacts should be
slow-closed manually (with closing springs restrained by
the safety pin) to observe contact alignment and to insure
that all mechanism parts move freely. A complete contact
inspection, including measurement of wipe and force,
should also be done.
To properly inspect contacts, the arc quenchers must be
removed.
At this time thoroughly inspect the inside
surfaces of the arc quencher side plates and inner
components.
1.2-Renewal Parts
The AKA breakers contain a variety of parts and
assemblies. Many of these parts and assemblies are
available
as replacement parts when the need arises. See
publication GEF4552, Renewal parts, for a complete listing
of these parts.
FRAME SIZE DRAWOUT MOUNTING STATIONARY
(Amperes) NOTES
250V.Dc 600V.
Ac POLES AKO
2000 1600 3 AKS-(*)-50
AKS-(*)-50H
--2 AKS-(*)-50V
-2000 3 AKST-(*)-50H
-1600 3 AKSU-(*)-50
(1)
The "H" suffix denotes extended short circuit ratings.
(2) Integrally fused models.
(*)
This digit identifies the trip device type as follows:
2 = EC-1 or EC-2A (De only).
4 = ECS
5
=SST (50/60 Hertz only)
6 = MicroVersaTrip
MOUNTING
AKD-5
AKS-(*)A-50 AKS-(*)S-50 (
1)
AKS-(*)A-50H AKS-(*)S-50H
AKS-(*)A-50V AKS-(*)S-50V (2)
AKST-(*)A-50H AKST-(*)S-50H (
1)
AKSU-(*)A-50 -(3)
N =Non automatic. In addition, all non-automatic 250 VDc breaker types carry the suffix letter D after their
frame number, e.q., AKS-N-50D.
EC-1 & EC-2A trip devices are the electro-mechanical type. ECS, SST, MicroVersaTrip'", RMS-9 and MVT-Plus or MVT-PM
units are Solid State. For detailed information on these trip devices refer to Sections 8 thru 11.
7 =
RMS-9
9 = MVT-PLUS or MVT-PM
4
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Table 2-AKR 75/100 Designations
FRAME SIZE MOUNTING TYPE
(Amperes) BREAKER DEEP PRIMARY
600V. Ac DESIGNATION DRAWOUT Sub- Stationary ESCUTCHEON STUD
2SOV. De
50/60 Hz. AKO AKD-5 AKD-6 AKD-8 Structure TYPE
3000 AKA-(*)-75 x Bar
x Tube
4000 AKA-(*)A-
75
x x Tube
AKA-(*)
B- 75
x x Fingers
3200 AKA-(*)C-75 x Fingers
AKA-(*)D-75 x x Fingers
AKA-(*)F-75 x x Fingers
AKA-(*)S-75 x Bar
AKR-(*)D-75H x Fingers
(j) 3200 AKR-(*)F-75H x Fingers
AKA-(*)-100 x
Tube
AKA-(*)A-100 x x Tube
AKR-(*)B-100 x x Fingers
6000 4000 AKA-(*)C-100 x Fingers
AKA-(*)D-100 x x Fingers
AKA-(*)F-100 x x Fingers
AKA-(*)S-100 x Bar
AKA-(*)W-100 x Bar
SPECIAL DC BREAKERS FOR FIELD SWITCHING
AAK-N-75F x Tube
AKA-NB-75F x x Fingers
4000 AKA-ND-75F x x Fingers
AKA-NF-75F x x Fingers
AKA-NS-75F x Bar
AKA-N-100F x Tube
AKA-N8-100F x x Fingers
6000 AKA-ND-100F x x Fingers
AKA-NF-1
OOF
'\
x x Fingers
AKA-NS-100F x Bar
AKA-NW-1
OOF
x Bar
Example: AKR-58-75 identifies a drawout, substructure-mounted breaker equipped with the SST trip device.
The EC trip devices are electro-mechanical, refer to GEi 86157 for detailed information.
Breaker Models
(*) This digit identifies
the trip device:
2 =
EC-1 B. De only.
4 =
ECS
5 =SST 50/60 Hertz only.
6 = MicroVersaTrip 50/60 Hertz only.
7 =RMS-9
9 = MVT-PLUS or MVT-PM
For detailed information on
these trip devices refer to
Sections 8 thru
11.
N = Non-automatic.
In addition, all
non-automatic 250V.
De breaker types carry the
suffix letter D after the
frame number,
e.g., AKR-NB-75D.
CD AKR-75H not available for DC applications.
BREAKER
WIDTH
(Inches)
25
25
33
25
;:s;:s
25
33
25
33
5
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SECTION 2-General Description
General Description
Type AKR low-voltage power circuit breakers are used for con-
trolling and protecting power circuits
in the low-voltage range
(usually
up to 600 volts). In serving this function, they are a
means of safely switching loads
and automatically clearing cir-
cuits when abnormal conditions occur. Among these condi-
tions, the more common are short circuits and sustained
overloads and undervoltages.
The type AKR breakers are of the "quick-make, quick-
break" description, having the feature of storing energy in
a
closing spring for quick release in closing. In closing,
some energy is transferred to an opening spring to be used
subsequently for fast tripping.
Knowledge of how the breaker is designed and how it
operates
will enable the purchaser to make proper use of
the breaker and to avoid mistakes in its operation. Specific
directions on adjustments and maintenance procedures
will be treated later.
The three main functional components of a breaker are its
mechanism, an assembly
comprising the conductive
members, and the interrupter.
The mechanism unit is designed to receive energy, store it,
and later (when called upon to do so) deliver it to close the
breaker contacts. It must be able to reverse its
commitment to close the breaker at any point upon the
activation of an automatic trip device (i.e., be "Trip-Free").
Finally, it also must be able to trip open a closed breaker
q\,Jicky
enough to minimize arc erosion and in such a
manner as to effect proper arc transfer to the arc runner.
The current-carrying members of the breaker are
assembled on the back frame,
which provides the
mechanical support required and also the insulating
structure needed. The conductive members are the studs
for external connections, movable and stationary contact
sets, pivots for the movable contacts, and provision for
mounting the current transformers.
The interrupter components are, in addition to the arcing
contacts, the arc runners mounted on the back base and
the removable arc quencher assemblies.
In addition to these basic components, a breaker may be
equipped with any combination of many accessories and
interlocking devices.
Individual breakers may differ in a variety of areas as
shown in Tables 1 and 2. A brief description of these areas
follow.
An outline drawing is available for each breaker frame size
showing critical dimensions. The drawing number appears
on the breaker nameplate and can be obtained from GE.
6
2.1-Frame Size
AKA 75 breakers are available in three frame sizes-3200
amperes A.C. and 4000 amperes D.C. There is also
available, for
replacement or hole filler application on AKO
or AKD5 switchgear a 3000 amperes A.C. frame.
AKA 100 breakers are available in
two frame sizes-4000
amperes A.C. and 6000 amperes D.C.
AKS 50
(replacement breaker for the AK50) is available in
two frame
sizes-1600 amperes A.C. and 2000 amperes
A.C. or D.C.
depending on trip device.
These values represent the
maximum continuous current
capability of the respective frames. However, each breaker
carries a specific rating which is determined by the current
sensor ampere rating or tap setting of the trip device with
which it is equipped.
Individual breaker rating data is shown in Table 5.
2.2-0 peration
There are Manual and Electrical models. The Manual
breaker has an operating handle which is used to manually
charge the mechanism closing spring. Figure 1 shows a
typical Manual breaker.
Fig. 1. Manually operated, AKO type
rhe Electrical breaker contains an electric motor which
charges the mechanism closing spring. External control
power is required to energize this motor and its control
circuit. A nameplate indicates what voltage is required by
the
motor circuit. Figure 2 shows a typical Electrical
breaker.
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Fig. 2. Electrically operated, AKO type
2.3-Mounting
AKR-75 and -100 breakers are furnished in both drawout and
stationary construction. Drawout breakers are
equipped with
features
which make them easy to install in or withdraw from
their associated switch-gear equipment. Stationary breakers
are designed to be mounted in a switchboard or enclosure.
Mounting consists of bolting the breaker frame to a support-
ing structure within the switchboard or enclosure. If control
power connections are needed, a suitable terminal board is
supplied.
The mounting type is identified by the second middle digit
in the breaker nameplate designation as follows:
AKR-4(t)-75, where
(t) = mounting type code letter per Table 3
Table 3-Mounting Type Codes
Code Breaker Type
Letter Drawout Stationary
None AKD
---
A AKD-5, 6
---
B Substructure
---
c AKD-6 Only
---
D AKD-8
---
F Substructure
---
s
---
AKR-75/100 (25" wide)
w
---
AKR-100 (33" wide)
2.4-Trip Device
There are six types of solid-state, direct-acting self-
powered
trip device systems associated with AKR
breakers.
These systems are for AC applications only. For
DC applications an electromechanical system is available.
The trip device system is identified by the first middle digit
in the breaker's nameplate designation as follows:
AKR-(t)
C-75
(t) = trip device code per Table 4
Table 4-Trip Device Codes
CODE
NUMBER TRIP DEVICE APPLICATION
2 EC
1 DC
3 Power Sensor2 AC
4
EC
AC
5 SST AC
6 MicroVersaTrip AC
7 RMS-9 AC
9 MVT-PLUS
or MVT-PM AC
'EC devices. See
Section 11.
2
Power Sensor devices are discontinued. See publications
GEK-7301 and GEK-7309 for detailed servicing
procedures.
2.5-Short Circuit Ratings
Short circuit ratings vary with the applied system voltage. On
240 VAC systems they are also dependent upon whether the
overcurrent trip device contains
an instantaneous trip element.
See Table 5.
7
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Table 5-Breaker Interruption Ratings
Frame
Size Breaker
(Amperes) Type
AKS-50
1600 AC
AKS-50H
AKSU-50
2000 AC AKST-50H
AKR-75
3200 AC
AKR-75H
AKR-75 (fused)
AKR-100
4000 AC
AKR-100 (fused)
2000
DC
AKS50
AKS 50V
4000
DC
AKR 75
6000 DC AKR 100
Q) With 200-2000 amp trip coils
®Consult factory for application data
8
Rated Maximum
Voltage {60 Hz
AC)
635
508
254
635
508
254
600
635
508
254
635
508
254
635
508
254
600
635
508
254
600
300V
DC
300V DC
300i/ DC
30 Interruption Rating
KA RMS Symmetrical
Instantaneous Trip Short
With Without Time
42
42 42
50 50 50
65 50
42
65 65 65
200 200 -
42 42
42
65 65
65
65 65
85 65
85 85 85
130 85
200 200 -
85 85 85
130 85
200 200 -
50 (j)
(2)
-
50 50 -
50 50 -
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SECTION 3-Storage, Safety & Maintenance
3.1-Storage
It is recommended that the breaker be put into service
immediately in its permanent location. If this is not
possible, the following precautions must be taken to insure
the
proper storage of the breaker:
1. The breaker should be carefully protected against
condensation, preferably by
storing it in a warm
dry room, since water absorption has an adverse
effect on the insulation parts.
Circuit breakers for
outdoor switchgear should be stored in the
equipment
only when power is available and the
heaters are in operation to prevent condensation.
2. The breaker should be stored in a clean location
free from corrosive gases or fumes. Particular care
should
be taken to protect the equipment from
moisture and cement dust, as this combination has
avery corrosive effect on
many parts.
3.2
CAUTION: IF THE BREAKER IS STORED FOR
ANY
LENGTH OF TIME, IT SHOULD BE
INSPECTED
PERIODICALLY TO SEE THAT
RUSTING HAS NOT STARTED AND TO
ASSURE GOOD MECHANICAL CONDITION.
SHOULD THE BREAKER BE STORED UNDER
UNFAVORABLE ATMOSPHERIC CONDI-
TIONS. IT SHOULD BE CLEANED AND DRIED
OUT BEFORE BEING PLACED IN SERVICE.
Each user
must maintain a safety program for the protection
of personnel, as well as other equipment, from the potential
hazards associated with electrical equipment.
The following requirements are intended
to augment the
user's safety program, but NOT supplant the user's respon-
sibility for devising a complete safety program. The follow-
ing basic industry practiced safety requirements are appli-
cable to all major electrical equipment such as switchgear or
switchboards. General Electric neither condones nor assumes
any responsibility for practices which deviate from the following:
1. ALL CONDUCTORS MUST BE ASSUMED TO BE ENER-
GIZED UNLESS THEIR POTENTIAL HAS BEEN MEASURED AS
GROUND AND SUITABLE GROUNDING CONDUCTORS HAVE
BEEN APPLIED
TO PREVENT ENERGIZING. Many accidents
have been caused by back feeds from a wide variety of
sources.
2. Although interlocks to reduce some of the risks are provided,
the individual's actions while performing service or maintenance
are essential to prevent accidents. Each person's knowledge;
his mental awareness; and his planned and executed actions
often determine if
an accident will occur. The most important
method of avoiding accidents
is for all associated personnel to
carefully apply a thorough :.mderstanding of the specific equip-
rrent from the viewpoints of it's purpose, it's construction, it's
opJration and the situations which could be hazardous.
All personnel associated with installation, operation and mainte-
nance of electrical equipment, such
as power circuit breakers
and other power handling equipment, must be thoroughly in-
structed, with periodic retraining, regarding power equipment
in
general as well as the particular model of equipment with which
they are working. Instruction books, actual devices and appro-
priate safety and maintenance practices such
as OSHA publica-
tions, National Electric Safety Code
(ANSI C2), The National
Electrical Code, and NFPA 70B Electrical Equipment Mainte-
nance must
be closely studied and followed. During actual
work, supervision should audit practices to assure conformance.
3. Excellent maintenance is essential for reliability and safety of
any electrical equipment. Industry publications of recom-
mended maintenance practices such as ANSl/NFPA 70B, Elec-
trical Equipment Maintenance, should
be carefully studied and
applied
in each user's formation of planned maintenance.
3.3
Both long and short term maintenance of all electrical equip-
ment
is essential for reliability and safety. Maintenance pro-
grams
must be tuned to the specific application, well planned
and carried out consistent with both industry experience and
manufacturer's recommendations. Local environment
must
always be considered in such programs, including such vari-
ables
as ambient temperatures, extreme moisture, number of
operations, corrosive atmosphere or major insect problems
and any other unusual
or abusive condition of the application.
One of the critical service activities, sometimes neglected,
involves the calibration of various control devices. These
monitor conditions
in the primary and secondary circuits,
sometimes initiating emergency corrective action such
as
opening or closing circuit breakers. In view of the vital role
of these devices, it
is important that a periodic test program
be followed. As was outlined above, it is recognized that the
interval between periodic checks will vary depending upon
environment, the type
of device and the user's experience. It
is the General Electric recommendation that, until the user
has accumulated enough experience to select a test interval
better suited to his individual requirements, all significant
calibrations be checked at
an interval of one to two years.
To accomplish this, some items, such as "EC" direct operating
trip systems for
low voltage breakers, must be tested with
primary current injection. Others can be adequately tested
using test sets. Specific calibration instructions on particular
devices typically are provided by supplied instruction books.
Instruction books supplied by manufacturers address
com-
ponents that would normally require service or maintenance
during the useful life of the equipment. However, they can
not include every possible part that
could require attention,
particularly over a very long service period
or under adverse
environments. Maintenance personnel
must be alert to dete-
rioration of any part of the supplied switchgear, taking ac-
tions,
as necessary to restore it to serviceable status.
Industry publications of recommended maintenance practices
such
as ANSl/NFPA 708, Electrical Equipment Maintenance,
should be carefully studied and applied
in each user's forma-
tion
of planned maintenqnce.
Some users may require additional assistance from General
Electric
in the planning and performance of maintenance.
The General Electric
Company can be contracted to either
undertake maintenance or to provide technical assistance
such
as the latest publications.
The performance and safety
of this equipment may be com-
promised by the modification of supplied parts or their re-
placement
by non identical substitutes. All such design
changes
must be qualified to ANSI/IEEE Standard C37.59.
The user should methodically keep wr(tten maintenance
records as
an aid in future service planning and equipment
reliability improvement. Unusual experiences should be
promptly communicated to the General Electric Company.
9
Courtesy of NationalSwitchgear.com

SECTION 4-Breaker Operation
Breaker Operation
The AKS-50, AKR-75 and AKR-100 breakers are closed by
the
discharging of the energy stored in the closing springs
of the breaker. As the closing springs are discharged, the
energy is directed into the closing cam of the breaker
which causes the moveable breaker contacts to be forced
against the stationary contacts, and, at the same time
causes the opening springs to be charged so they may
open
the breaker during a subsequent opening operation.
4.1-Manual Closing
Manually operated breakers are equipped with a handle
which extends from the escutcheon of the breaker.
Alternately rotating the closing handle counterclockwise
then clockwise through approximately 120 degrees of
rotation through four complete cycles will cause the
breaker to close. During the four counterclockwise
movements and the first three clockwise movements of the
handle, the springs are progressively charged. After
approximately seven degrees travel of the fourth clockwise
handle movement, the spring charge mechanism is driven
"over
center" and the energy stored in the closing springs
is directed into the closing cam and causes the breaker to
close. A charge-indicator, numbered one to four, visible
through the breaker escutcheon, indicates the number of
complete handle movements that have been performed.
CONTROL
SOURCE
-,
I
Fl
I
_J
L
cc
4.2-Electrical Closing
On electrically operated breakers, the closing springs are
charged
by a gear motor. With the springs discharged, volt-
age applied to the control circuit will energize the motor
through the "G" switch contacts-see figs. 3A & 38. The mo-
tor, through the gear reduction output crank, compresses the
closing springs until they are fully charged. As this fully
charged position
is reached, mechanically operated switch
"G" reverses its shown position, deenergizing the motor. In
the fig. 3A diagram switch "F" reverses its position and es-
tablishes a circuit for the "X" relay. At the
same time, a me-
chanical prop is positioned to prevent the discharge of the
fully charged closing spring.
With the closing spring pr-opped fully-charged, the breaker
is ready for closing. This may be accomplished electrically
by depressing the closing button on the bre'aker (if so
equipped) or by a remote closing switch. Operation of the
closing switch energizes the "X" relay, which in turn
energizes the closing solenoid. This removes the prop,
releasing
the closing springs to close the breaker.
As
the closing relay is energized, it energizes anti-pump
relay "W". If the closing switch is maintained closed, the
anti-pump relay will remain picked-up to prevent a second
closing operation on the breaker in the event it is tripped
open automatically. The closing impulse must be released
and reapplied before a second
closing operation can occur.
TC
LEGEND
CC -CLOSING SOLENOID
F -CUTOFF SWITCH, CLOSED
WHEN CLOSING SPRING IS
FULLY CHARGED.
G -CUTOFF SWITCH. OPEN WHEN
CLOSING SPRING IS
FULLY CHARGED.
L -AUXILIARY SWITCH
M -CHARGING MOTOR
PB -CLOSE PUSHBUTTON ON
BREAKER ESCUTCHEON,
OPTIONAL.
TC -SHUNT TRIP DEVICE
W -ANTI-PUMP RELAY
X - CONTROL RELAY
Fig. 3A. Elementary diagram for electrically operated drawout breaker.
Contact positions are shown with breaker open and closing springs discharged.
TYP #5688736 "R" series.
10
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4.2.1-Alternate Control Circuit
Later production breakers use the electrical control circuit
shown
in Fig. 38. This circuit is similar to the circuit shown
in Fig. 3A except that the X-relay and 'F' switch are elimi-
nated.
The motor is energized through the 'G' switch and the W-
relay contact.
The 'G' switch deenergizes the motor when
the closing
springs are charged and the prop is engaged.
With the closing spring propped fully-charged, the breaker
is ready for closing. This may be accomplished electrically
by depressing the closing switch on the breaker (if so
CONTROL
SOURCE
FU
REMOTE
CLOSE
u------<>- - -1 ~ - ..,
)...
t
~ PB
w
L
cc w
equipped) or by a remote closing switch. Operation of the
closing switch energizes the W-relay, which in turn
energizes the closing solenoid. This removes the prop,
releasing the
closing springs to close the breaker.
If the closing switch
is maintained closed, the anti-pump re-
lay will remain
picked-up to prevent a second motor charge
and closing operation on the breaker
in the event it is tripped
open automatically. The closing impulse
must be released
and reapplied after the closing springs are fully-charged be-
fore a second closing operation can
occur. The charging
time is typically 1
to 3 seconds depending on voltage and
the maximum
time permitted is 5 seconds.
~-
~FU
J: TRIP
L
TC
LEGEND
CC -CLOSING SOLENOID
G -CUTOFF SWITCH. OPEN WHEN
CLOSING SPRING IS
FULLY CHARGED.
L -AUXILIARY SWITCH
M -CHARGING MOTOR
PB -CLOSE PUSHBUTTON ON
BREAKER ESCUTCHEON,
OPTIONAL.
TC ......_SHUNT TRIP DEVICE
W -ANTI-PUMP RELAY
Fig. 38. Alternate elementary diagram. Contact positions are shown breaker open and
closing springs discharged. TYP #5688736
"8" series.
11
Courtesy of NationalSwitchgear.com

SECTION 4-Breaker Operation
4.3-Connections
In all electrical connections good joint conductivity is a
must.
When making power connections to stationary
breakers, the mating joint surfaces must be clean and have
a
smooth finish. They should be parallel and firmly bolted
or clamped together. In addition, the bus or cable
conductors must have ample ampacity to prevent
overheating.
The outgoing connections to breaker accessories and
control devices must be in accordance with the specific
wiring diagram applicable to that breaker.
4.3.1-Stationary Breaker
Control connections to stationary breakers are made to a
terminal board mounted on the breaker. Figure 4 shows
typical closing and tripping connections. If equipped with
an overcurrent trip device which includes a ground fault
element for use on 4-wire circuits, an additional terminal
board is provided on the breaker for connecting to the
equipment-mounted neutral sensor (physically located in
the neutral conductor).
4.3.2-Drawout Breaker
On drawout breakers the control circuits terminate in the
breaker compartment on the stationary portion of
separable secondary disconnects -see fig. 5.
~000000
12
TERMINAL BOARD
MOUNTED ON FRONT
OF BREAKER
AT
UPPER LEFT
CUSTOMER
CONNECTIONS
2
CLOSE
3 4 5 6 7 8 9 10
.._,,_,
CLOSING
SOURCE
.._,,_,
TRIP
SOURCE
.._,..__,
UV
TRIP
SOURCE
TO AUX. SW
"a" CONTACT
(-) (+)
REVERSE
CURRENT
DEVICE
POTENTIAL
SOURCE
Fig. 4. Control connections to stationary breakers-front view
1
FUSE
/\ /\ /\ /\ /\ /\ /\
765432
(Y)}
(X)
CLOSING
SOURCE
/\ /\ /\ /\ /\/\ /\
765432
STATIONARY SECONDARY DISCONNECT BLOCKS
LOCATED
AT TOP OF COMPARTMENT -
POSITIONS B AND C FURNISHED
ONLY WHEN-REQUIRED I
Fig. 5. Control connections to drawout breakers - front view of breaker compartment
Courtesy of NationalSwitchgear.com

4.4-Tripping
In the closed position, the breaker movable contacts are
held in by a toggle linkage. The breaker is tripped open by
displacing a mechanism latch which allows this toggle
linkage to collapse. The trip latch is rigidly fastened to a
horizontal trip shaft running from left to right through the
breaker. In turn, the trip shaft carries paddles actuated by
the manual trip button and the various other trip devices -
overcurrent, reverse current, shunt trip, undervoltage,
open fuse lockout. Viewing the breaker from the right,
rotating the trip shaft counterclockwise trips the breaker;
clockwise movement resets the mechanism latch.
In addition
to tripping the breaker, some devices hold the
breaker trip free, i.e., prevent the contacts from closing
even though a closing impulse is applied to the
mechanism. Such devices are the undervoltage, bell alarm
and lockout, electric lockout, open fuse lockout, and the
key operated locks.
These devices and the drawout mechanism interlocks must
be in the reset position before the breaker can be closed.
4.5-Charging and Closing Using
the Maintenance Handle
In the absence of control power, an electric breaker can be
closed manually by using the maintenance handle to
charge the closing springs. Referring to Fig. 6:
(a) With the breaker open and springs discharged
release holding pawl slide per instruction label (2).
(b) Install maintenance crank (1) (568B386G1) to the motor
gear reducer shaft
on the front right side of the breaker. Rat-
chet the maintenance crank up and down until the springs are
fully charged as indicated by the distinct click as the prop is
set. This prevents
any further charging of the closing springs.
After the prop is set do not apply undue force to the
maintenance handle.
(c) Depress
the "Spring Discharge" lever (3) located
under the horizontal support on the front frame. The
springs should discharge and if the latch is properly reset,
the
breaker will close. Some style breakers, because of an
interlock in the switchgear, can not be manually closed in
the
fully engaged position.
(d)
Open the breaker by pushing the trip button (4).
1. Maintenance crank
2. Instruction label
3. Spring discharge lever
4. Trip button
Fig. 6. Maintenance handle charging
13
Courtesy of NationalSwitchgear.com

SECTION 5-Contact Maintenance
Contact Maintenance
Breakers subjected to frequent interruption of high
currents may eventually require replacement of their
contacts. The general rule for determining need of
replacement is the loss of one-half or more of the mass of
the contact tip material. Roughening or light pitting of the
contact surface does not indicate loss of ability to carry or
interrupt current.
For proper operation of the breaker, the contact structures
must be correctly adjusted. Various interrelated
adjustment parameters are involved. Specific amount of
contact pressure and wipe must exist between moveable
and stationary contacts. The arcing, intermediate and main
contact assemblies must engage and disengage in a
prescribed sequence;
and with breaker open, an adequate
gap must exist between the movable and stationary arcing
contacts.
5.1-Slow Closing the Breaker
To perform contact maintenance work the breaker
operating mechanism must be "slow-closed", i.e. manually
driven and controlled at will instead of in the high-speed
manner produced by spring discharge. Slow closing is
achieved by
preventing the closing springs from acting on
the
mechanism. The breaker is arranged for slow closing
by manually charging the springs and then securing them
in this compressed state by inserting a restraining "safety
pin" see Fig. 7.
Following the inspection period,
a. Recharge the closing springs.
b. Remove the safety pins from the guide rods, return
them to their storage clips.
14
5.1.1-Electrical Breaker
Referring to Fig. 7:
a. Attach maintenance handle (1) and charge the
closing springs until the crank roller contacts prop (4).
b. Insert safety pins (3) into the holes in the guide rods
(2).
c. Release the prop by depressing closing lever (5). The
safety pin now takes the full force of the spring and
restrains it. Now free from spring influence, the breaker
contacts can be inspected and moved at will to the fully
closed position by means of the maintenance handle.
5.1.2-M anual Breaker
a. Operate the breaker closing handle through 3112
complete movements to charge the closing springs.
b. Insert the safety pins into the guide rods.
c. Continue to operate the closing handle (4th
downstroke) until the spring crank goes over center,
applying full spring force to the safety pin. Closing motion
now can be continued and is completely controlled by the
breaker closing handle.
WARNING: DO NOT APPLY CONTROL
VOLTAGE OR RACK THE BREAKER INTO
THE TEST OR
CONNECTED POSITIONS
WHILE THE SAFETY PINS ARE IN USE.
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1. Maintenance
2. Guide rods
3. Safety pins
4. Prop
5. Closing springs
Fig. 7. Installation of safety pin
5.2-Arc Quencher Removal and
Inspection
The arc quenchers should be inspected at the regular in-
spection period. If item 1 is eroded to .125 of an inch from
original conture or item 2
is cracked, Fig. 8, the arc quencher
should be replaced.
5.2.1-Removal and Replacement
Referring to Fig. 8:
a. Be sure breaker is open.
b. Loosen nuts (4) and remove the two slotted head jack
screws.
c. Remove two hex head bolts (5) that mount channel-
shaped retaining bar
to side support (6).
d. Remove channel-shaped retaining bar.
(Continued next page)
15
Courtesy of NationalSwitchgear.com

SECTION 5-Contact Maintenance
1., 2. & 3. Barriers
4. Nuts
5. Hex head bolts
6. Side support
7. Protective,barrier
B. Phase barrier screws
9. Mounting bolts
Original design
Fig. 8. Arc quencher removal
e. Lift arc quenchers clear of the movable arcing contact
arms.
f.
Inspect arc quenchers carefully and replace if
necessary.
g.
During replacement, tighten jack screw nuts (4) first,
then
the two hex head bolts that secure the channel-
shaped retaining bar to side sheet. DO NOT
OVERTIGHTEN THESE TWO BOLTS.
16
5.3-Separation of Front and
Back Frames
In order to perform some repair and replacement
operation, the front frame must be separated from the back
frame. Proceed
as follows: referring to Fig. 9.
a. Open the breaker, manually compress the closing
springs and insert the safety pin as described under
SLOW CLOSING, Section 5.1. Restraining the springs
properly positions the main operating cam to facilitate the
separation operation.
Courtesy of NationalSwitchgear.com

il-
1. Opening springs 4. Flux shifter actuator bracket 7. Side support bolts
2. Clevis pin
3. Front/back frame
connector
5. Auxiliary switch
operating rod
6. Phase barriers
8. Position interlock
9. Arc quencher retainer bolts
Fig. 9. Front and back frame separation details
b. Remove the two opening springs (1) (on lower part of
the breaker) from the outside pole units.
c. Remove the clevis pin (2) from the center pole unit.
d. Disconnect the
programmer CT wire harness at each CT
and remove any tye wraps holding leads to back frame.
e. Disconnect the flux shifter actuator bracket from the
crossbar assembly (4).
f. Remove the auxiliary switch operating rod (5).
g. Remove outside phase barriers (6).
h. Remove side support bolts (7).
i. Remove position interlock on AKO, AKO 5, AKO
6 type (8).
j. Remove arc quencher retainer and bolts (9).
k. Remove the six nuts from the back frame using a
socket wrench with an extension. These include the two
nuts at the top of the frame.
I. Check along the trip shaft for a mechanical
interference or connection between the overcurrent trip
device and the trip paddles. Remove mechanical
connection if present, or if interference exists, use extreme
care when removing or reassembling front and back
frames
to avoid mechanical breakage of trip devices.
When reassembling the
front and back frames, both should
be positioned vertically so that the trip shaft is horizontally
aligned. It is recommended that the breaker back frame
be fastened to a suitable mounting surface so that the front
frame can be supported by a sling or hook as the bolts are
being installed.
17
Courtesy of NationalSwitchgear.com

SECTION 5-Contact Maintenance
5.4-Back Frame Assembly
The breaker backframe consists of a frame assembly to
which the pole units are mounted. Each pole unit is
connected to a common crossbar which provides for
simultaneous pole unit operation by the breakers
mechanism. A
typical backframe is shown in Fig. 10.
The pole units consist of a molded base which supports
the line and load stud assemblies, stationary and moveable
contact assemblies and the actuating linkage.
The stationary main contact assembly (9) comprises of a
spring loaded contact fingers. Interlocked with these are
the intermediate contact fingers (7) whose contact surface
project beyond that of the main such that the
intermediates make before, and break after the mains.
Mating with the stationary contacts is a moveable contact
assembly consisting of multiple main and intermediate con-
tact fingers (1 O) and (8). These moveable contact fingers
pivot on a stationary pin
(11 ), which fasten them to the lower
contact block. The insulated link (13) which is attached to
the breaker crossbar (1) and moveable contact assembly
gives the open and close motion to the
contact arm.
The stationary arcing contact assembly (3) is a separate
set
of contact fingers, pins, springs and pivot block.
The moveable arcing contact assembly (5) consists of
multiple contact arms carried on two moveable pins (6)
and (12).
The arcing contact arms interleave the main
contacts and pivot with them about pin (6). This relative
motion is obtained by the insulating links (13) from the
contact arms to the breaker crossbar.
BACK FRAME ASSEMBLY
1. Crossbar 7. Stationary intermediate contact
2. Pole unit
8. Moveable intermediate contact
3. Stationary arcing contact 9. Stationary main contact
4. Pin-stationary arcing 10. Moveable main contact
5. Moveable arcing contact 11. Pivot pins
6.
Pin-moveable arcing 12. Drive pins
13. Insulated link
Fig. 1 O. Front view of back frame assembly
18
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