Siemens GMI Series User manual

SIEMENS
5kVand 15kV
Vacuum Circuit Breakers
TypeGMI
Instruction
Installation
Operation
Maintenance
SGIM-3268E
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•••••••
Hazardous uni+ ... ,,.,,.,
Will cause death, serious personal injury or
Always de-energize and ground the equipment before
maintenance.
Maintenance should be
performed only by qualified personnel. The use of
unauthorized oarts in the repair of the equipment or tampering by unqualified
personnel will result
in dangerous conditions which will cause severe personal
injury or equipment damage. Follow
all safety instructions contained herein.
IMPORTANT
The information contained herein
is general in nature and not intended for specific
application purposes. It does not relieve the user
of responsibility to use sound
practices
in application, installation, operation, and maintenance of the equipment
purchased. Siemens reserves the right to make changes
in the specifications
shown herein or to make improvements at any time
without notice or obligations.
Should a
conflict arise between the general information contained in this
publication and the contents of drawings or supplementary material or both, the
latter shall take precedence.
QUALIFIED PERSON
For the purpose
of this manual a quaiified person is one who is familiar with the
installation, construction or operation
of the equipment and the hazards involved.
In addition, this person has the following qualifications:
(a) is trained and authorized to de-energize, clear, ground, and tag circuits and
equipment
in accordance with established safety practices.
(b) is trained in the proper care and use of protective equipment such as rubber
gloves,
hard hat, safety glasses or face shields, flash clothing, etc., in accordance
with established safety practices.
(c) is trained in rendering first aid.
SUMMARY
These instructions do not purport to cover all details or variations in equipment, nor to provide for every possible
contingency to be
met in connection with installation, operation, or maintenance. Should further information be
desired or should particular problems arise which are not covered sufficiently for the purchaser's purposes, the
matter should be referred to the local sales office, listed on back
of this instruction guide.
The contents
of this instruction manuai shall not become part of or modify any prior or existing agreement,
commitment or relationship.
The sales contract contains the entire obligation of Siemens Power Transmission &
Distribution Inc. The warranty contained in the contract between the parties is the sole warranty of Siemens Power
Transmission & Distribution Inc. Any statements contained herein do not create newwarranties or modify the existing warranty.
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kV and 1 uum
Circu1 B
Introduction and Safety
Introduction
Qualified Person
Signal Words
Dangerous Procedures
Field Service Operation
Receiving, Handling and Storage
Introduction
Receiving Procedure
Shipping Damage Claims
Handling Procedure
Storage Procedure
Indoor Storage
Outdoor Storage
Soace Heating
Installation Checks and Initial Functional Tests
Introduction
Inspections,
Checks and Tests without Control Power
De-Energizing Contra: Power
Spring
Discharge Check
Removal from Lower Cell
Removal from
Upper Celi
Removal in Outdoor Non-Walk In Enclosures
Physical Inspections
Manual Spring Charging
Check
As-Found and Vacuum Check Tests
Automatic Spring Charging
Check
Final Mechanical Inspections without Control Power
Interrupter/Operator Description
Introduction
Vacuum Interrupters
and Primary Disconnects
Primary Disconnects
Phase Barriers
Stored Energy Operating Mechanism
Modes of Operation -Mid-1991 and After
Modes of Operation -Discussion
Spring Charging
Mode
Closing Mode
Trip Free Mode
Opening Mode
Rapid Auto-Reclosing Mode
Modes of Operation -UP to Mid-1991
Modes of Operation -Discussion
Spring Charging
Mode
Closing Mode
Trip Free Mode
Opening Mode
Rapid Auto-Reclosing Mode
Closing and Opening Springs
Trip Free Operation
Damper
Manual Spring Charging
Spring Charging Motor
Close Solenoid, Trip Solenoid
and Anti-Pump Relay
Secondary Disconnect
Auxiliary Switch
MOC (Mechanism Operated Ceil) Switch
TOC (Truck Operated Cell) Switch
Limit Switches
Standard Schematic Diagrams
Capacitor Trip Device
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
4-7
4
4
4
4
4
5
6
6
6
6
6
7
8-20
8
8
9
9
9
10
10
10
11
11
11
11
12
12
12
12
13
13
13
14
14
14
14
15
15
15
16
16
16
17
17
17
Undervoltage Release
Interlocks
Trio Free Interlock
Rating Interlock
Circuit Breaker Frame
Ground Disconnect
Circuit Breaker
Handling Wheeis
Racking Mechanism
Maintenance
Introduction and Maintenance Intervals
Recommended Hand Toois
Recommended Maintenance and Lubrication
Removal from Switchgear
Checks of the Primary Power Path
Cleanliness
Check
Inspection of Primary Disconnects
Checks of the Stored Energy Operator Mechanism
Maintenance
and Lubr!cation
Fastener
Check
Manual Spring Charging and Contact Erosion Checks
Damper Assembly Check
Electrical Control Checks
Check of the Wiring and Terminals
Check of the Secondary Disconnect
Automatic Spring Charging
Check
E'ectrical Close and Trip Check
Checks of the Spring Charging Motor
High-Potential Tests
Vacuum Integrity
Check
High Potential Test Voitages
Vacuum Integrity Test Procedure
As-Found Insulation
and Contact Resistance Tests
Insulation and
Contact Resistance Test Equipment
lnsuiation and Contact Resistance Test Procedure
Inspection and C!eaning of Breaker Insulation
Functional Tests
Overhaul
Introduction
Circuit Breaker Overhaul
Rep!acement at Overhaul
Rep!acement
of Closing Springs
Replacement of
Opening Spring
Replacement of Closing
and Tr!pping Solenoids
Replacement
of Anti-Pump Relay
Replacement of the Auxiliary Switch
Replacement of Motor Cut-Off Switch
Replacement of Trip Latch Reset
Check Switch
Replacement
of LS3 -Mid-1991 and After
Replacement
of LS3 Up to Mid-1991
Replacement
of Spring Dump Switch
Replacement
of Damper Assembly
Replacement of Spring Charging Motor
Replacement of Primary Disconnect Fingers
Replacement of Vacuum Interrupters
Preparation
Vacuum Tube Removal
Vacuum Tube Replacement
Periodic Maintenance and Lubrication Tasks
Troubleshooting
Appendix
19
19
20
20
20
20
20
20
21-26
21
21
21
21
22
22
22
23
23
23
23
24
24
24
24
24
25
25
25
25
25
25
25
25
25
26
26
27-35
27
27
27
27
27
28
28
28
28
28
28
29
30
30
30
30
31
31
31
32
36
37
39
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Introduction and Safety
Introduction
The GMI family of vacuum circuit breakers is designed to meet
all the applicable ANSI, NEMA and
IEEE standards. Success-
ful application and operation of this equipment depends
as
much upon proper installation and maintenance bythe user as
it does upon the careful design and fabrication by Siemens.
The purpose of this Instruction Manual
is to assist the user in
developing safe and efficient procedures for the installation,
maintenance and use
of the equipment.
Contact the nearest Siemens representative
if any additional
information
is desired.
Qualified Person
Powercircuitbreakersoperateathighvoltages
and have
spring-loaded mechanical parts
which operate at high speed.
When operated improperly,
this equipment
will causedeath,personal
injury and property
damage.
To avoid electrica: shock. bumsano entang:ement
in moving parts this equipment must be installed,
operated and maintained only by qualified
persons thoroughly familiar with the equipment.
instruction manuals and mawings.
Forthe purpose ofthis manual and product labels, a"Qualified
Person"
is one who is familiar with the installation, construction
and operation
of this equipment, and the hazards involved. In
addition, this person has the following qualifications:
• Training and authorization to energize, de-energize, clear,
ground and tag circuits and equipment
in accordance with
established safety practices.
• Training
in the proper care and use of protective equipment
such
as rubbergloves, hard hat, safetyglasses, face shields,
flash clothing, etc.,
in accordance with established safety
procedures.
• Training
1n rendering first aid.
2
Signal Words
The signal words "Danger", "Warning" and "Caution" used in
this manual ·indicate the degree of hazard that may be encoun-
tered by the user. These words are defined
as
Indicates an imminentlyhazardoussituation which,
if not avoided, will result in death or serious injury.
Warning-Indicates apotentiallyhazardoussituation which,
if not avoided, could result in death or serious injury.
Caution -Indicates a potentially hazardous situation which,
if not avoided, may result in minor or moderate injury.
Dangerous Procedures
In addition to other procedures described in this manual as
dangerous, user personnel must adhere to the following:
1. Always work on a de-energized breaker. Always de-ener-
gizeabreaker, and remove
it from the metal-clad switchgear
before performing any tests, maintenance or repair.
2. Always perform maintenance on the breakerafterthespring-
charged mechanisms are discharged (exceptfor test of the
charging mechanisms).
3. Always let an interlock device or safety mechanism perform
its function without forcing or defeating the device.
Field
Service
Siemens can provide competent, well-trained Field Service
Representatives
to provide technical guidance and advisory
assistance for the installation, overhaul, repair and mainte-
nance of Siemens equipment, processes and systems. Con-
tact regional service centers, sales offices or the factory for
details.
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IVI g, Handlin and Sto
Introduction
Type GM! Vacuum Interrupter Circuit Breakers are normally
installed
in assembled metal-clad switchgear, and the Switch-
gear Instruction Manual (SG-3258) contains the Receiving,
Handling and Storage instructions for assembled metal-clad
switchgear.
This manual covers the Receiving, Handling and Storage
instructions for Type GM! circuit breakers shipped separately
from the switchgear. This section of the manual
is intended to
help the user identify, inspect and protect the circuit breaker
prior to its installation.
Receiving Procedure
Make a physical inspection of the shipping container before
removing orunpacking thecircuitbreaker. Checkfor shipment
damageor indicationsofrough handling bythe carrier. Check
each item against the manifest to identify any shortages.
Accessories such as the manual charging lever, the racking
crank and the plug jumper are shipped separately.
Shipping Claims (When Applicable) -Follow nor-
mal shipment damage procedures, which should include:
1. Check for visible damage upon arrival.
2. Visible damage must be noted on delivery receipt. and
acknowledged with driver's signature. Notation, "Possible
internal damage, subject to inspection" must be
on delivery
receipt.
3. Notify Siemens Sales office immediately of any shipment
damage.
4. Arrange for carrier's inspection. Do not move the unit from
its unloading point.
Handling Procedure
1. Carefullyremovethe shipping cartonfromthecircuitbreaker.
Keep the shipping pallet for later use if the breaker
is to be
stored prior to its installation.
2. Inspect for concealed damage. Notification to carrier must
take place within
15 days to assure prompt resolution of
claims.
3. Each circuit breaker should be appropriately lifted to avoid
crushing the side panels of the breaker, or damaging the
primary disconnect subassemblies.
Heavy Weight
Can cause death,
serious injury, or property
damage.
Obtain the services of a qualified rigger prior to
hoisting the circuit breaker to assure adequate
safety margins
1n the hoisting equipment and
procedures to avoid damage.
TypeGM! circuitbreakersweigh between385to 575 pounds
(175to
261 kg). See Table A-4, Technical Data in Appendix.
4. The palleted circuit breaker can also be moved using a
properly rated fork-lift vehicle. The pallets are designed for
movement by a standard fork-lift vehicle.
s""'""'" .. Procedure
1. Whenever possible, install circuit breakers in their assigned
switchgear enclosures for storage. Follow instructions con-
tained
in the Switchgear Instruction Manual.
2. When the breaker will be placed on its pallet for storage, be
surethe unit
is securelybolted to the palletand covered with
polyethylene film at least
10 mils thick.
Indoor -Whenever possible, store the circuit breaker
indoors. The storage environment must be clean, dryand free
of such items as construction dust, corrosive atmosphere,
mechanical abuse and rapid temperature variations.
Outdoor -Outdoor storage is not recommended.
When no other option
is available, the circuit breaker must be
completelycovered and protected from rain, snow, dirtand all
other contaminants.
Space -Space heating must be used for both indoor
and outdoorstorage to prevent condensation and corrosion.
When stored outdoors. between 150 to 200 watts per breaker
of space heating
is recommended. If the circuit breakers are
stored insidethe switchgearenclosures, and the switchgear
is
equipped with space heaters, energize the space heaters.
3
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Installation Checks and Initial Functional Tests
Introduction
Tris sectio.1 providesa description of the inspectio1s, checks
ard tests to be per'ormed or the circ1.;it breaker prior to
operatior.
in tre metal-clad switchgear.
Inspections,
Checks and Tests without Control Power
Vacuurr. circciit breakers are normally sr:pped witr t'"ieir pri-
~ary contacts open anci he;~ spri'.1gs discharged. However,
it:s critical to firstverify
tre discharged coridition of!hespring-
loaded mechanisms afte' de-energizing cortrol power.
De-Energizing
Control Power in Switchgear - Wren tre
circJi'. breaker is mou'lted in switchgear, open t"'ie control
powerciisco.-:nectdevice
in :he!Tietal-cladswitchgearcubicle.
Figure 1
srows the location o: this discon'."lect ir. a standard
GM switchgear assembly.
Tre con:rol power disconnect dev:ce is located or.
the device
panel above
the :ower c:~cuit breaker and below the upper
circuit breaker. Figure 1
srOVl/S a pi.; lout type fJse 'lOlder.
Removal
of the 'use rolder de-ererg·zes cort'OI power to tre
circJi! breaker ir the respec'.!ve switchgea~ cell. In so""ie
sw'.tcrgearassemb
ies, amolded casecircJit breaker is used
in lieu o: the pJll out type fuse raider. Opering this circuit
breaker accomplishes
the same result: control power is dis-
con:iected.
Spring Discharge Check (Figure 2) -Perform t."ie Spring
Discha~ge Check before removing the circuitbreaker ~rom the
paEet or re~ovi:ig it !rom tre switchgear.
Tre
sprj'."lg discr.arge creek consistsof simply performing tre
following :asks in the ordergiven. Thisc1eckassi..:res:hatboth
the tripping and
clos;'."lg springs are fully discharged.
... ,: .-.
.........
Figure 1: Co!ltrol Power Disconnects in Switchgear.
4
A DANGER
Hazardous voltages and high-speed
mechanical parts.
Wiil cause death, severe personal Injury. or
property damage.
Read ir;str;iction manuals, observe safety
1ns:ruct1ors and use
c;ualif1ed persor.rel.
1. Press red Trip pus"'ibutto'."I.
2 Press black Close pushbutton.
3. Again press red Trip pushbutton.
4. Veri'y Spring Cordition l:idicator shows DISCHARGED.
5. Veri'y Mair. Contact StatJs Indicator shows OPEN.
Removal from Lower Cell In Indoor (If not on raised pad)
and Shelter-Clad Outdoor Switchgear -
1. Open the circuit breaker.
2. If the circuit breaker is
in the Connect position, insert the
racking crank on the racking screw on the front
of the
breaker cell, and push
in. This action operates the racking
interlock latch. Figure 3 shows racking
of a circuit breaker
in the upper cell -the process is similar for a breaker in the
lower cell. Rotate the racking crank counterclockwise until
the breaker is
in the Test position. (If the circuit breaker is in
the Disconnect position, turn the racking crankclockwise to
rack the circuit breaker from the Disconnect position to the
Test position). If the racking crank is not of the "Captive"
type, constant inward pressure is required during racking to
maintain engagement with the racking mechanism.
3. With the circuit breaker
in the Test position and OPEN, de-
energize control power to the circuit breaker. Figure 1
shows the location of control power disconnects in a
normal unit.
• •
• +=
c:
~A 1..,f~:o.., D
I
~
I
-
.,
-
--
Manual
ICl ose •
Figure 2: Front Panel of GMI Circuit Breaker.
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Installation Checks and Initial Functional Tests
4. Perform the Spring Discharge Check. and verify that the
circuit breaker is OPEN
and the closing spring indicator
shows DISCHARGED.
5. Insert the racking crank on the racking screw on the front of
thebreakercell, and push in, as described in step2. Rotate
the racking crank counterclockwise until
the breaker is in
the Disconnect position. The breakercan now be removed
from the cubicle.
6. The circuit breaker is now free
to be rolled out on the floor
using the handles
as shown in Figure4. The wheels of the
circuit breakerare virtually
at floorlevel (unles theswitchgear
is installed
on a raised pad}, and one person can easily
handle the unit.
g
.
. • •
' • '
Ill
Q
"" II!
__ I - -
Figure 3: Racking Circuit Breaker in Switchgear.
Figure 4: Removal
of Circuit Breaker.
Removal from Upper Cell (Indoor and Shelter·Clad Out·
doorSwitchgear)·Removaloftheupperbreakerinatwo-high
assembly is similar
to removal of a breaker from a lower cell.
with several additional steps.
Figure 5 shows one of the two breaker extension rails being
inserted into the fixed rails within the upper cell o! two-high
switchgear equipment. The rails engage locking pins in the
fixed rails to secure them in position.
The procedure for removal of an uppercircuit breaker is:
1. Open the circuit breaker.
2. If the circuit breaker is in the Connect position, insert the
racking crank
on the racking screw on the front of the
breaker cell, and push
in. This action operates the racking
interlock latch. Figure3 shows racking
of a circuit breaker
in the uppercell . the process issimilar for a breaker in the
lower cell. Rotate the racking crank counterclockwise until
the breakerisin the
Test posrtion. (If the circuit breaker is in
the Disconnect position, turn theracking crank
clockwise to
rack the circuit breaker from the Disconnect posrtion to the
Test position). If the racking crank is not of the "Captive"
type, constant inward pressure is required during racking
to
maintain engagement with the racking mechanism.
3. With the circuit breaker in the
Test position and OPEN, de·
energize control power to the circuit breaker. Figure 1
shows the location of control power disconnects in a
normal unit.
4. Perform the Spring Discharge Check, and verify that the
circuit breaker is OPEN and the closing spring indicator
shows DISCHARGED.
5. Insert the
two extension rails into thefixed rails. Be sure the
extension rails are properly secured in place. (This can
be
doneat step 7 ifpreferred.)
6. Insert the racking crank on the racking screwon thefront of
the breakercell, and push in, asdescribed in step 2. Rotate
the racking crank counterclockwise until the breaker is in
the Disconnect position.
7. If you have not yet installed the extension rails, do so now.
Note that some difficulty may be experienced installing
the
extension rails if the circuit breaker is in the Disconnect
Figure 5: Use
of Extension Rails for UpperCompartment.
5
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Installation Checks and Initial Functional Tests
position. Ifdifficulty is encountered, rack the circuit breaker
to the
Test position, install the extension rails, and then rack
the circuit breaker to the Disconnect position.
HeavyWeight
Can cause death,
serious Injury, or property
damage.
Always use extension
~ails to rerr.ove or ins:a·1
c'rc:.;it breaker ir :he upper ceil or in ce~ls not
irstalledat floor
~evel.
8. Move the breakerrelease latch to the left and pull thecircuit
breaker
out from the Disconnect position. The breaker is
now free to be rolled out on the twoextension rails using the
handles
on the front of the circuit breaker.
9. Remove the breaker from the two extension rails using the
approved Siemens breaker lifting device.
10. Lift the two extension rails and withdraw them from the
switchgear.
Figure 6: Manual Charging of Closing Springs.
6
Removalfrom UpperandLowerCell in OutdoorNon-Walk
In Enclosures or for Indoor Switchgear Installed on a
Raised Pad -Because the floor level in non-walk in outdoor
enclosures is approximately 6 inches above grade (founda-
tion) level, the lower breaker in either a one-high or two-high
sectior
of switchgear must be removed using the preceding
procedure for upper breaker removal.
The approved breaker lifting device should be used for re-
moval
of both lower and u~per breakers frory-, the extension
rails
of outdoornon-walk in enclosures.
Physical Inspections
1. Verify thatrating of thecircuitbreakeriscompatiblewithboth
the system and the switchgear.
2. Performavisual shippingdamagecheck. Cleanthebreaker
of all shipping dust. dirt and foreign material.
Manual Spring Charging Check
1. Insert the manual spring charging lever into the manual
c'large handle socket as shown in Figure 6. Operate the
leverup and down until the spring corditionindicatorsl-iows
the closing spring isCharged.
2. Repeat the Spring Discharge Check.
3. Verify that the springs are discharged and the breaker
primary contacts are open
by indicator positions.
21659-93
Figure 7: Split Plug JumperConnected to Circuit Breaker.
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Installation Checks and Initial Functional Tests
As·Found and Vacuum Check Tests -Perform and record
theresultsofboththeAs-Found insulation testand thevacuum
check high-potential test. Procedures for these tests are
described in the Maintenance Section
of this manual.
Automatic Spring Charging Check
Note: A temporarysourceof control powerand test leadsmay
be required if the control power source has not been con-
nectedto the switchgear. (Refer
to the specificwiringinforma-
tion and rating label for your circuit breaker to determine the
voltage required and where the control voltage signal should
be applied. Usually, spring charging power is connected to
secondarydisconnectfingers S016andSD15, closingcontrol
powertoSD13and8015,andtripping powertoSD1 andSD2.)
When control power is connected to the GMI circuit breaker,
the closing springs should automatically charge.
The automatic spring charging features
of the circuit breaker
must
be checked. Control power is required for automatic
spring charging to take place.
1. Open control power circuit by removing pullout fuse holder
shown
in Figure 1.
2. Install breaker end of split plug jumper(if furnished) shown
inFigure7tothecircuitbreaker.
The plugjumperissecured
by means of screws, over the circuit breaker's secondary
contacts.
3. Install the switchgear end of the plug iumper shown in
Figure 8 to the secondary disconnect block inside the
switchgearcubicle. The jumperslides into place. The plug
jumper interconnects all control power and signal leads
(e.g., remote trip and close contacts) between the switch-
gearand the circuit breaker.
4. Energize (close) the control power circuit disconnect (Fig-
ure 1
).
Figure 8: Split Plug JumperConnected to Switchgear.
5. Use theClose and Trip controls{Figure 2) to first Close and
then Open the circuit breaker contacts. Verify contact
positions visually
by observing the Open/Closed indicator
on the circuit breaker.
6. De-energizecontrol power by repeatingStep 1. Disconnect
the plug jumper from the switchgear first and next from the
circuit breaker.
7. Perform the Spring Discharge Check again. Verify that the
closing springsare dischargedand the primary contactsof
the GMI circuit breaker are open.
Final Mechanical Inspections without Control Power
1. Make a final mechanical inspection of the circuit breaker.
Verify that the contacts are in the Open position. and the
closing springs are Discharged.
2. Check the upper and lower primary studs and contact
fingers shown in Figure
9. Verify mechanical condition o!
finger springs and the disconnect studs.
3. Coat movable primary contact fingers (Figure 9) and the
secondary disconnect contacts {Figure 9 and 22) with a
lightfilm ofSiemensContactLubricantNo. 15-171-370-002.
4. The GMI vacuumcircuit breakeris ready for installation into
its assigned cubicle
of the metal-clad switchgear. Refer to
removalproceduresandre-installthecircuitbreakerintothe
switchgear.
5. Refer to the Switchgear Instruction Manual for functional
tests
of an installed circuit breaker.
Figure 9: Rear of GMI Breaker with Primary Disconnects.
7
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Interrupt er /Operator Description
Introduction
The Type GMI vaci.;u~ circui1 breaker is o' drawout construc-
tior designed for use
in medi;.im vo!1age. metal-clad switch-
gear.
The GMI circJit breakerconforrrs tothe requirements of
ANSI standards C37.20.2. C37.04, C37.06. C37.09 and
C37.010.
GM! circuit breakers consist of t'lree vacuum interrupters, a
stored energy operati:ig mechanism, necessary electrical
controls and irterlockdevices, disconnec1devices to connect
the breakerto both pri~ary ar.d cortrol power ard an operator
hoJsir.g. On some
circ;.1it breaker ratings insulatirg barriers
are located between the vacJt..m interrupters or along the
sides.
This section describestne operationof eacr. '.:lajorsubassem-
bly as an aid
ir the operation, installation, maintenance and
repair of the GMI vacuum circuit breaker.
Figure 10: Front View ofGMI Breaker.
8
Vacuum Interrupters and Primary Disconnects
The operating principle of the GMI vac:.ium interrupter is
simple. Figure 11 is a cutaway view of a typical vacuum
interrupter. The entire assembly
is sealed after a vacuum is
established. The interrupterstationarycontactisconnectedto
the upper disconnect stud of the circuit breaker. The inter-
rupter movable contact
is conrected to the lower disconnect
stud and driving!'1echanism ofthe circuit breaker. The metal
bellowsassemblyprovidesa secure seal around the movable
contact. preventing loss of vac;.Jum while permitting vertical
motion ofthe movable contact.
I
ll'I Y /JJ------
(' ~ .. ..
~-···
2
~J·;
. r.
s
····---MOVING
CONTACT
CURRENT
CONNECTION
Figure 11: Cutaway View otGMI Vacuum Interrupters.
When the two contacts separate an arc
is initiated which
continues conduction up to the following current zero.
At
current zero, the arc extinguishes and any conductive metal
vapor which has been created by and supported the arc
condenses on the contacts and on the surrounding vapor
shield. Contact materials and configuration are optimized to
achieve arc motion and to minimize switching disturbances.
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Interrupter/Operator Description
Primary Disconnects -Figure 12 is a side view of the circuit
breaker with a side phase barrier removed
to show details of
the primarydisconnects. Each
circ~it breakerhasthree upper
and three lower primary disconnects. Upper primary discon-
nects are connected to the stationary contacts
of the vacuum
irterrJpters.andthe lowerprirr.arydisconnectstothemovable
contacts. Each disconnect arm has a set
of multiple spring
loaded fingers that mate with bus bars
in the metal-clad
switchgear.
The number of fir:gers in the disconnectassembly
varies
witi-i t!le conti:iuous and/or momentary rating of the
c;rcuit breaker.
There are three insulating push rods. Each push rod connects
the movable co:itact of
ore of the vacuum interrupters to the
jack shaft driven
by the closing and tripping mechanism.
Flexible con'lectors ensure secure electrical connections be-
tween themovable contacts
of each interrupteranditsbottom
primary disconnect.
Figure 12: Upper and Lower Primary Disconnects.
Phase Barriers -Phase bar~ier cor.figurations vary among
GMI breakers depending on voltage and con:inuoJs current
ratings.
Figure 13 isa rear view of acircuit breaker that shows the two
outer(phase to ground) insulating barriers and two ir.terphase
barriers.
The interprasebarriersare r.ot provided o:i all circuit
breaker ratings. Thesefour plates ofglasspolyester''lsula:ing
material are attached to the circuit breaker and provide suit-
able electrical insulation between
the vacuum interrupter pri-
mary circuits and the housing.
Stored Energy Operating Mechanism
The stored energy operatir.g mechanism of the GMI circuit
breaker is an integraled arrangemer.1
o' sp~ings. solenoids
and mechanical devices desigr.ed to provide a :1Lmber of
critical functions.
The energynecessaryto closearidope'l !he
contacts of the
vacuu~ ir.terrupters is stored in powerfJI
trippir.g and closing springs. These springs are
nor~ally
charged automatically. but there are provisior.s for manual
charging. The operating mechanism that controls charging,
closing and tripping functions is fully trip-free. i.e
.. spring
charging does not automatically change the position of :he
primarycontacts. and the closing function may
be overr'dde'"l
by the tripping function at any time.
Note: Two differenl latch syster..s have been used in GMI
circuit breakers.with changeover from one design
to the other
occurring
in mid-1991. T:iisi'.lstructionma'lualdescribesboth
designs.
Pages 10-
11 describe lhe operation of tre mechanism used
beginning in approximately mid-1991.
Pages 12-13 describe the operation of the mecha'"lism used
from 1989until approximately mid-1991.
Figure 13: Breakerwith lnterphase and 0Jterphase Barriers.
9
Courtesy of NationalSwitchgear.com

Interrupter /0
rator
MAIN
LINK
120
JACK
SHAFT
PLATE
TRIP
SOLENOID
ARMATURE
TRIP
ACTUATOR
152
TRIP
SHAFT
79
TRIP
HATCHET
99
~JACK
SHAFT
217
-- POINT"A"
14a: Breaker Open-Closing Springs Discharged.
Modes
of Operation -Mid-1991 and After
Pages 10-11 describe the operation of the mechanism used
beginning
in approximately mid-1991.
This mechanism can be identified byobserving the close latch
above the spring charging motor
on the left side of the circuit
breaker. Refer to Figure 18a.
The close latch is installed on
the close shaft assembly
72, and includes a hardened latch
face. This face contacts a bearing which is part of the close
hatchet assembly
105. If the mechanism has a close hatchet
which bears directly
on the closeshaft, refer to pages 12-13for
the description of your mechanism
Modes
of - Discussion
Some maintenance procedures are more easily understood
when the operating mechanism modes of operation are de-
scribed
in detail. The next few paragraphs explain the five
modesor status conditions (charging, closing, trip-free, open-
ing and rapid auto-reclosing) of the stored energy operating
mechanism.
Note:
All discussion of modes of operation assumes that the
reader
is viewing the operator from the front, or from the right
hand side.
Charging Mode -
Figures 14a and 1 Sa show several
key components of the operator mechanism
in positions cor-
responding to the breaker open, with the closing springs
discharged (Figure 14a) and charged (Figure 15a). Figure
16a shows portions of the operator mechanism that manually
or electrically charge the closing springs.
The drive cam (20),
the closing springcrankarms (Figure19)and condition
indicatorcam (18) are directlykeyed to the main cam shaft (3).
The main cam shaft rotates counterclockwise. The closing
springs are attached to the crank arms, and are extended
during the charging cycle.
10
on
TRIP
SOLENOID
266
BANANA
LINK
113
DRIVE-
CAM
20
CAM --
FOLLOWER
115
JACK
SHAFT
PLATE
0
TRIP
~SOLENOID
ARMATURE
-~ ·n
_j_ I __ TRIP
-:T ACTUATOR
152
-LATCH FACE
-~TRIP
SHAFT
79
ROLLER
Figure 15a: Breaker Open-Closing Springs Charged.
Figure16a shows the ratchet wheel (15) which
is free to rotate
about the main cam shaft (3). The ratchet wheel
is driven by
either the charging motor or the manual charge handle socket
(52). When the springs are charged electrically, the motor
eccentric(100)introducesa rocking motion intothe drive plate
(13)
As this plate rocks back and forth, the lower pawl (24-1)
(which
is connected to the drive plate) imparts counterclock-
wise rotation of the ratchet wheel (15), one tooth at atime.
The
upper pawl (24-2) acts as a holding pawl during electrical
charging.
When the springs are charged manually, up and down pump-
ing action of the spring charging handle
in the manual charge
handlesocket(52) causesthe pawl plate (11) to rock backand
forth through the movement of the manual charging link (48).
The upper pawl (24-2) drives the ratchet plate counterclock-
wise during manual charging, and the lower pawl (24-1)
becomes the holding device.
At the beginning of the charging cycle, ratchet pin (16) is at the
6 o'clock position. The ratchet pin
is connected to the ratchet
wheel. Upon being advanced by ratchet action to the
12
o'clock position, this pin engages the drive arms (8) which are
keyed to the main cam shaft. Consequently, counterclockwise
rotation ofthe ratchet wheel causes the ratchet pin to drive the
main cam shaft counterclockwise. When the ratchet pin
reaches the 6 o'clock position, the closing springs are fully
charged. Driving pawl (24-1)
is disengaged, the spring
condition indicator cam (
18) has rotated allowing the spring
charged flag (132) to drop into the lower (charged) position,
which also operates the motor cutoff switch
(LS 1) and spring
charged switch (LS2) (258) (see Figures 17a and 27). The
closing springs are restrained fully charged by close hatchet
(22) against close shaft (72).
Courtesy of NationalSwitchgear.com

Interrupter /0 rator
J
.._.'""'""' ... Mode (Figure 17a) -Energizing the close solenoid
(265) pulls the solenoid armature against the closing shaft
actuator (75) and causes the close shaft (72) to rotate approxi-
mately 15°.
If the closing springs are charged, the close
hatchet (22) will be released by this rotation allowing the main
cam shaft (3) to be driven by the closing springs. Depressing
the manual close button
on the operator panel causes the
rotation of the close shaft (72) by the lower end of the close
shaft actuator (75). Rotation of the main cam shaft (3)
in a
manual closing operation
is identical to that of an electrical
closing operation.
As the main cam shaft (3) rotates, the cam
follower (115)
is driven by drive cam {20), and the main link
(120)
is forced outwards, and rotation of the jack shaft assem-
bly (217) occurs. There are three drive links attached to Point
"A" of each of the three jack shaft drive plates. Each drive link
is connected to the movable contact of one vacuum inter-
rupter. Closing rotation (counterclockwise) of the jack shaft
assemblyclosesthe contacts
of the three vacuum interrupters.
During closing operation, rotation of jack shaft assembly(217)
forces the opening , tripping) spring into its charged
position.
Trip Free Mode - If at any time during breaker closing, the trip
shaft (79) (Figure 14a) operates
as a result of either an
electrical or mechanical trip, trip hatchet (99) is free to rotate.
When the trip hatchet (99) rotates, cam follower (115)
is
displaced by drive cam (20) without motion of the jack shaft
(217). Mechanical trip free operation
is provided by manual
tripping, electrical tripping and/or the mechanical interlocks.
Opening Mode -Opening or tripping the vacuum interrupter
contacts
is accomplished by rotation of the trip shaft (79)
Rotation maybe produced either electrically, byenergizingthe
trip solenoid (266) (Figure 15a), or manually by pressing the
trip button. Energizing the trip solenoid causes the upper arm
of the trip actuator (152) to rotate counterclockwise. Pressing
the trip button causes the trip actuator lower arm to move,
ion
17a: Closing Mode
again producing rotation ofthe trip shaft.
All ofthe linkages are
trip free, and tripping or opening
is unaffected by charging
status of the closing springs or position of the drive cam (20).
Auto-Reclosing Mode (Optional}- The closing springs
are automatically recharged by the motor driven operating
mechanism when the breaker has closed.
The operating
mechanism
is capable of the open-close-open duty cycle
required for rapid auto-reclosing. Atriplatch checkswitch and
arelay (delay
on dropout) preventrelease ofthe closing spring
energy
if the trip hatchet (99) is not in its reset position. This
ensures the mechanism does not operate trip free
on an
instantaneous reclosure.
CLOSE HATCHE
ASSEMBLY
105
CLOSE SHAFT
72
CLOSE HATCHET
22
FRONT
Mechanism -Mid-1991 and After Mechanism -Up to Mid-1991
(Viewed from Left Side) (Viewed form Left Side)
(Refer to Pages 10-11) (Refer to Pages 12-13)
Figure 18a: Identification of Mechanism Vintage
11
Courtesy of NationalSwitchgear.com

lnterru r/Operator
0 Trip
Solenoid
266
Trip Solenoid
---~- Armature
Jack
Shaft
Plate
Trip
Actuator
152
Trip
Hatchet
99
Trip
Shaft
79
Close
Hatchet
22
Jack
Shaft
217
14b: Breaker Open-Closing Springs Discharged.
Modes of Operation -Up to Mid-1991
Pages 12-13 describe the operation of the mechanism used
from 1989 until approximately mid-1991.
This mechanism can be identified byobserving the close latch
above the spring charging motor
on the left side of the circuit
breaker. Referto Figure1
Bb. The close hatchet22 has alatch
face which bears directly
on the close shaft 72. If the close
hatchet includes a bearing which contacts a hardened latch
installed
on the close shaft, refer to pages 10-11 for the
description of your mechanism.
Modes of - Discussion
Some maintenance procedures are more easily understood
when the operating mechanism modes of operation are de-
scribed
in detail. The next few paragraphs explain the five
modesor status conditions(charging, closing, trip-free, open-
ing and rapid auto-reclosing) of the stored energy operating
mechanism.
Note: All discussion of modes of operation assumes that the
reader
is viewing the operator from the front, or from the right
hand side.
Mode -Figures 14b and 15bshow several
key components of the operator mechanism
in positions cor-
responding to the breaker open, with the closing springs
discharged (Figure 14b) and charged (Figure 15b). Figure
16b shows portions of the operator mechanism that manually
or electrically charge the closing springs.
The drive cam (20),
the closing spring crankarms (Figure19)and spring condition
indicatorcam (18) are directly keyed
to the main cam shaft (3).
The main cam shaft rotates counterclockwise. The closing
springs are attached to the crank arms. and are extended
during the charging cycle.
Figure 16b shows the ratchet wheel ( 15) which is free to rotate
about the main cam shaft (3).
The ratchet wheel is driven by
12
ion
Main
Link
120
0
0
0
0
00
0
,.,._-~~-Trip Solenoid
Armature
Trip
Hatchet
99
Figure 15b: Breaker Open-Closing Springs Charged.
either the charging motor or the manual charge handle socket
(52). When the springs are charged electrically, the motor
eccentric(100) introducesa rocking motion intothe drive plate
(
13). As this plate rocks backand forth, the lower pawl (24-1)
(which is connected to the drive plate) imparts counterclock-
wise rotation ofthe ratchet wheel (15), one tooth at a time.
The
upper pawl (24-2) acts as a holding pawl during electrical
charging.
When the springs are charged manually, up and down pump-
ing action of the spring charging handle
in the manual charge
handlesocket(52) causes the pawl plate
(11 )to rock backand
forth through the movement of the manual charging link (48).
The upper pawl (24-2) drives the ratchet plate counterclock-
wise during manual charging, and the lower pawl (24-1)
becomes the holding device.
Atthe beginning of the charging cycle, ratchet pin (16)
is at the
6 o'clock position. The ratchet pin is connected to the ratchet
wheel. Upon being advanced by ratchet action to the.
12
o'clock position, this pin engages the drive arms (8) which are
keyed tothe main cam shaft. Consequently, counterclockwise
rotation ofthe ratchet wheel causes the ratchet pin to drive the
main cam shaft counterclockwise. When the ratchet pin
reaches the 6 o'clock position, the closing springs are fully
charged. Driving pawl (24-1)
is disengaged, the spring
condition indicator cam (18) has rotated allowing the spring
charged flag (132) to drop into the lower (charged) position,
which also operates the motor cutoff switch (LS1) and spring
charged switch (LS2) (258) (see Figures 17b and 27).
The
closing springs are restrained fully charged close hatchet
(22) against close shaft (72).
Closing Mode (Figure 17b) -Energizing the close solenoid
(265) pulls the solenoid armature against the closing shaft
actuator (75) and causes the close shaft (72) to rotate approxi-
mately
15°. If the closing springs are charged, the close
Courtesy of NationalSwitchgear.com

Interrupter/0 erator ription
Close
Shaft---#-(
72
0 0
16b: Pawl and Ratchet Drive.
Pawl
Plate
11
Drive
Plate
13
hatchet (22) will be released by this rotation allowing the main
cam shaft (3) to be driven by the closing springs. Depressing
the manual close button
on the operator panel causes the
rotation of the close shaft (72) by the lower end of the close
shaft actuator (75). Rotation of the main cam shaft (3)
in a
manual closing operation
is identical to that of an electrical
closing operation.
As the main cam shaft (3) rotates, the cam
follower (115)
is driven by drive cam (20), and the main link
(120)
is forced outwards, and rotation of the jackshaft assem-
bly (217) occurs. There are three drive links attached to Point
"A" of each of the three jack shaft drive plates. Each drive link
is connected to the movable contact of one vacuum inter-
rupter. Closing rotation (counterclockwise) of the jack shaft
assemblyclosesthe contactsofthe threevacuum interrupters.
During closing operation, rotation of jack shaft assembly (217)
forces the opening (i.e., tripping) spring into its charged
position.
Trip Free Mode - If at any time during breaker closing, the trip
shaft (79) (Figure 14b) operates as a result of either
an
electrical or mechanical trip, trip hatchet (99) is free to rotate.
When the trip hatchet (99) rotates, cam follower (115)
is
displaced by drive cam (20) without motion of the jack shaft
(217). Mechanical trip free operation
is provided by manual
tripping, electrical tripping and/or the mechanical interlocks.
Opening Mode -Opening or tripping the vacuum interrupter
contacts
is accomplished by rotation of the trip shaft (79).
Rotation maybe produced eitherelectrically, byenergizing the
trip solenoid (266)
(Figure 15b), or manually by pressing the
trip button. Energizing the trip solenoid causes the upperarm
of the trip actuator (152) to rotate counterclockwise. Pressing
the trip button causes the trip actuator lower arm to move,
again producing rotation ofthe trip shaft. All ofthe linkages are
trip free, and tripping or opening
is unaffected by charging
status of the closing springs or position
of the drive cam (20).
Close
Solenoid
265
Close
Shaft
Actuator
75
Close
Shaft
72
Spring
Condition
Indicator
Cam
18
Main
Cam
Shaft
3
Main
Cam
Follower
115
Figure 17b: Closing Mode
Main
i...::,....::::~-'-;-~-Cam
20
Manual Close
==~~)°tActuator (153)
H------Jack
Shaft
Jack
r--+--Shaft
Plate
217-3
Rapid Auto-Reclosing Mode (Optional)- The closing springs
are automatically recharged
by the motor driven operating
mechanism when the breaker has closed. The operating
mechanism
is capable of the open-close-open duty cycle
required for rapid auto-reclosing. Atrip latch checkswitch and
arelay(delay
on dropout) preventrelease ofthe closing spring
energy if the trip hatchet {99)
is not in its reset position. This
ensures the mechanism does not operate trip free
on an
instantaneous reclosure.
CLOSE SHAFT
72
\ I
\ Q Q I
~J.
FRONT--..!
Mechanism -Mid-1991 and After Mechanism -Up to Mid-1991
(Viewed from Left Side) (Viewed
form Left Side)
(Refer to Pages 10-11) (Refer to Pages 12-13)
Figure 18b: Identification of Mechanism Vintage
13
Courtesy of NationalSwitchgear.com

Interrupter/Operator Description
Closlng and Opening Springs · Th estored energyassembly
consists of two dual closing
sp rings and a single opening
spring.
Figure 19 shows th e three springs and their linkages
to the charging devices. The two closing springs are con-
nected tocrankarmsmount
ed on therotating main camshaft.
Theclosing springs areextended, and charged,
by rotation of
thecrankarms co nn ectedtothe movableen ds ofthe springs.
The
fi xed endsofthese spr in gs are attach ed toa supportarm,
which in tum is bo lt ed to the structure of the circuit breaker.
Th e opening sp ri ng is connected to the jack sha ft. When the
circuit breaker closes, rota
ti on of the jack shaft causes the
opening spring pushrod
to compress andchargethe opening
spring. Consequently, the opening
sp ring is automatically
charged whenever breaker contacts are closed.
Trip Free Operation- TheGMI circuitbreakerismechanically
and electrically trip free. This important function enables the
breaker to
be tripped bef ore, after or during a closing opera-
tion. Whenever the circuit breaker trip shaft is mov
ed as the
result
of manual orel ect rical signals or m ec hani ca l int er locks,
a) aclosed breaker will open.
b) a breaker in the process of
closing will not complete the close operation and will remain
open, or
c) an open breaker will not be ab le to be closed.
Damper- GMI circuitbreakersare equippedwitha sealed, oil-
filfed, viscous damper, or shock absorber (Figure 19). The
purposeof thisdamperis
to li mitovertravel and rebound ofthe
vacuum interrupters' movable contacts during theconclusion
of an opening operation. Th e damper action affects only th e
end of an opening operation.
::--:-·- .. - --:-~
Figure 19: Closing and Opening Springs, Spring Chargi ng
Motor and Damper.
14
The cylindrical body of the damper is secured to the breaker
frame, with a yoke.
Th e damper's piston and striker tip
protrude from the
oppo site end of this cylinder (the lower end
as installed on the
br eaker). A striker block is fixed within an
ou ter tube, which is guided by the cylindrical body of the
damper. The end of the outer tube is attach
ed to the breaker
jack shaft.
Th e outertube and (inner) damper remain uncoupledunt il the
end
of theopeni ng operation isreached. At this time, thetube's
striker bl
ock contac ts the damper piston. to begin control of
movable contact dynamics.
Manual
Spring Charging - Manual charging of tn e closing
springs is accomplish
ed using a lever in lieu of th e spring
chargingmotor.
Figure 20 showstheprincipalcompon er .ts of
the manual spring charging mec hanism.
Themanual
spr ingcharging leveris inserted intoarectangular
socketin theha
nd operator. Thissocketisaccessiblelhrough
thefront panel
of the circuitbreaker. Moving lhe lever up and
down in a cranking
or pumping motion causes rot at io:i of the
internal spring charging components.
Note: Manual spring charging components will be damaged by
overcharging.
Manual cha'.ging aclion must be suspe nded whe'.l the operator sees !he
'C
harged' status 'ndicato ~ appear o~ th e :ron! _cariel of t'1e circ(;it br eake~
a nd hears the sound of imp ac! agairst '.he interna: .:;1osing laiC .'\.
. ..._ .... -:::--
~.::..-..:::: ..
. ~-:.::: =:::.:-
__ ...... _____ __
Figure 20! Manual Charging of the Cl os i ng Spri ngs .
Courtesy of NationalSwitchgear.com

Interrupter/Operator Description
Spring Charging Motor -Figure 19 shows the spring charg-
ing motor mounted at the bottom of the left side
of the circuit
breakerhousing. A mounting bracketholds the motorfirmly in
place. A universal motor is used to permit operation
on either
AC
or DC control power.
The motor control circuits call for automatic charging
of the
springs
by the motorwhenevercontrol power is available and
the springs are discharged.
The springs automatically re-
charge following a closing operation.
Electrical connections to the motor utilize quick disconnect
terminations for easy inspections
or removal.
Close Solenoid, Trip Solenoid and Anti-Pump Relay -
Figure 21 showsthe twosolenoidscontrolling operationofthe
circuit breaker
by external electrical signals.
When the closesolenoid is energized itcauses the twoclosing
springs to
be released from their extended or charged state.
Thisforces the three insulating push rods
to move themovable
vacuum interruptercontactsverticallyupwards, and close the
circuit breaker.
Theanti-pumprelay
(Figure 41)electrically isolates signalsto
the close solenoid such that only one releasing action
by the
close solenoid can occur during each application ofthe close
command.
The circuit breaker must be tripped, the springs
rechargedandtheclosing signalremoved(interrupted)before
the close solenoid can
be energized the second time.
Wher. the tripsolenoidisenergized. itallowsrotation of thejack
shaft
by the tripping spring. This rotation pulls the insulating
push rods attached to the movable contacts of the three
vacuur;. interrupters. and the circuit breaker contacts are
opened.
Electrical connections to the close solenoid and trip solenoid
are made through quick disconnect terminations.
Figure 21: Close (Right) and Trip (Left) Solenoids.
Secondary Disconnect -Signal and control power is deliv-
ered to the internal circuits of the breaker
by an arrangement
of movable contact fingers mounted on the left side of the
circuit breaker. These fingers are shown in
Figure 22.
When the circuit breaker isracked into the Test or Connected
positions in the metal-clad switchgear. these disconnect fin-
gers engage a mating disconnect block on the inside
of the
switchgear shown in
Figure 23. These electrical connections
automatically disengage when the circuit breaker is racked
from the Test to the Disconnect position.
Allofthecontrolpowernecessarytooperatethecircuitbreaker
is connected to this disconnect block inside the switchgear.
The external trip and close circuits and status indicators are
also connected to this same disconnect block.
21 660·93
Figure 22: Secondary Disconnects on Circuit Breaker.
Figure 23: Secondary Disconnect Inside Switchgear.
15
Courtesy of NationalSwitchgear.com

Interrupter/Operator Description
Auxiliary Switch · Figure 24 shows the b_reaker moun:ed
auxiliary switch. This switch provides auxiliary contacts
1or
control of circJit breaker closing ard !ripping fu.1cfors. Con-
tacts are available for use in relaying and exter1al logic
circL.:lts. Thisswitch is driven by lirkagescor.nected tothe jac"
shat!. The auxiliaryswitch cwtains both 'b' (Norm~lly Closec:J)
and ·a· (Normaily Open) cortacts. When the c1rcu1t breaker :s
open, t:ie·b' switchesareclosedand:he ·a· switchesare open.
MOC(MechanismOperated Cell)
Switch_- Figures 25 and 26
show the pri!lcipal components that provide optional control
11exibility wher operatirg the circuit breaker in the Test and
Connected positions.
Figure25 shows tr·e MOC switcr. operating arm that projects
from the right side
of thecircuitbreaker, just a_bove the bottor.-
rail structure. TheMOCswitchoperating arm
1s partof theiack
Figure 24: Auxiliary Switch.
Figure 25; MOC Switch Operating Arm on CircuitBreaker.
16
sraft assembly. and directly reflects the open or closed
position of :he ::ireaker primary contac:s.
As the
circL.:it breaker is racked into the appropriate position
i:is:de the switchgear, the MOC sw;tch operating arm passes
a w;:ing protective cover pla!e. and engages the pa.1tograph
linkage
show'1 /1 Figure 26. Operation of the c1rcu1t breaker
causes t1e pantograph linkage to '.rar:sfer
mo:~or. to the MOC
swi!ches loca!ed above
tre pantograor.. Fie 'a' ard 'b'
cor:tac1s
car be ~Jsed ;'.1 relaying and contro! logic schemes.
All circuit breakers contain
t'"ie MOC switc.1 operati:ig arm.
However. MOC switches are provided
ir. tre switchgear only
when spec:fied
The breaker e:igages tr.e MOC a..ix:liary switch
oriy in_ the
co1rected (operating) posit:orur.lessar. opt1on~1_ 1est pos1t1on
pickup is soecified in tre contrac:. I'. a te~t_pos:t1on p1<?k~p 1s
included. the breaker will engage the a..ix1l1ary switch 1n ooth
posi!iors (Figure 26). Up !o 24 stages
~ay be provided.
TOC (Truck Operated Cell) Switch · Figure 26 srows the
optional
TOC celi switc'"l. Piis swi!cr isooerated by the c1rcu1t
breaker as i: is racked i:ito the Con:iect oos1t10'1.
Various combina~;ons o' 'a' and ·b' contacts may ne optionally
specified. These switchesprovidecontroland logicindication
that a breaker in the cell has achieved the Con:-iect (ready to
operate) position.
Figure 26: MOC
and TOC Switches Inside Switchgear.
Courtesy of NationalSwitchgear.com

Interrupter/Operator Description
Limit Switches (Figure27) - The motor cutoff switch (LS 1) is
used to sense the position
of the driven mechanisms. This
switch de-energizes the charging motor when the Charged
position of the closing springs is reached. When
the closing
springs are discharged, this switch energizes the control
circuit powering
the spring charging motor.
Spring charged switch (LS2) operates simultaneously with
motor switch (LS1
). The spring charged switch allows the
close solenoid to
be energized only when the springs are
charged. ar.d also is part of
the anti-pump circuitry.
The trip latch check switch (LS3) operates when the trip latch
linkage is
in the rese1 position. It also is driven by operating bars
that sense when
the breaker is in either the Test or Connected
position inside
the switchgear. Control circuitry prevents an
electricalrelease of theclosing springsunless the breaker is either
in the Test or Connected position. or is out of the compartment.
The spring dumpswitch(LS4) operates when the circuit breaker
isremoved
from, or is being inser1ed into. the cubicle.
Standard Schematic Diagrams
Note: Figure 28a shows a typical schematic for a circuit
breaker which is not specifically intended for reclosing appli-
cation.while Figure28bshowsabreakerforreclosingservice.
Figure28c sl">ows abreakerwithcapacitortripping. These are
typical -refer to the specific drawing
for your project.
Inspection of
the schematic diagrams shown in Figures 28a·
28c provides a clear picture of the logic states
of the various
devices for the three basic control functior.s.
These are:
1) automatic charging of the closing springs: 2)
electrical closing of the primary contacts and 3) electrical
tripping of the primary contacts.
Figure 27: Circuit Breaker Limit Switches.
Automatic spring charging
by charging motor occurs when
secondary control power is available. and motor cutoffswitch
LS1 has not operated. The springs are automatically re-
charged after each closing
opP.rC1tion.
Electrical closing occurs with closing control power applied
and when a// of the following conditio1s exist:
1) External
control switch CS/C is closed: 2) Anti-pump relay 52Y is not
energized: 3) Auxiliary switch 52b indicates
the breaker is in
open position: 4) Limit switch LS3 shows that the trip latch has
been reset and the circuit breaker is in
the Test or Connected
position,
or is out of the compartment: and 5) Limitswitch LS2
indicates that the closing springs are charged. Electrical
tripping occurs with tripping control power applied and when
the auxiliaryswitch52ashows the breaker is closed, and a trip
signal is provided
by the control switch CS!T or the protective
relays. While external control power is required
for either
electrical closing or tripping,
the circuit breakercan be manu-
ally charged. closed and tripped wilt-out external control
power.
Capacitor Trip Device (Optional)
The capacitor trip deviceis an auxiliary tripping option provid-
ing ashortterm means
of storingadequateelectricalenergy to
ensure breaker tripping.
This deviceis appliedin breaker installations lacking indepen-
dent auxiliary control power
or station battery. In such instal-
lations. control power is usually derived from the primary
source.
In the event of a primary source fault, or disturbance
with attendant depression
of the primary source voltage, the
capacitortrip devicewill provideshort term trippingenergyfor
breaker opening
due to relay operation.
17
Courtesy of NationalSwitchgear.com

lnterru rator n
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! FUSE _ : : I
-'·'---c:;;::~~=======~==========----------:-----:--r-
DC
i
LS1
LS2
LS3
LS4
l-(«CJ»)--'--.--------+--- I I I
"-"' ~I i +gs *~ ~~ +~
I I G R I
I I 2 2 I
I I I
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-1--{~)--~--- : : ~I : l:
FUSE I J.. I 1 10
1 I
_r_ I <-') </'J cs
~ : ¢E' : :~ ~ 61
w I I I G R I
I I I 2 2 I
2 I I I I
. +---'
so)''" :f~=
52 '°"
' b •
1-' sT:"
roo ''r'
: 14 I
I r1o
7C
I
DC MO
POWER POWE!<
SUPPLY SUPfli..Y
so
3
"
so
"
SOL.
)
,6r-,"
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so
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so,h
t'
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't
9A
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521
: 10A
f
52
5
!O
____ 1~~
28a: DC Control Power (Non-Reclosing). 28b: AC and DC Control Power (Reclosing).
• Motor Cutoff Switch
• Spring Charged Switch
•Checks Trip Latch Reset and Blocks
Electric Close while Racking 'Test' to
'Connect'
• Spring Dump Switch
52/a • Aux. Switch, Open when Brk. is Open
52/b •Aux. Switch, Closed when Br!<. is Open
52Y • Anti-Pump Relay
52T •Opening Solenoid (Trip)
52SRC • Spring Release Solenoid
52X • Reclosing Control Relay
L ___________ _J
• Spring Charging Motor
• Secondary Disconnect
• Control Switch Close }
•
Control Switch Trip Typical
• Red Indicating Lamp Remote
•Green Indicating Lamp Devices
•White Indicating Lamp
Notes on Schematic
Arrangement
Schematics are shown with:
1.Closing Springs Discharged
2.Breaker Open
3.Breaker Located
in Test, Con-
nect or Withdrawn Position
Note that, in this condition, the trip
latch
is free to reset, but is tempo-
rarilyblocked
until the closingsprings
are partially recharged. Prior to full
spring charge, LS3 (NO) closes, and
LS3 (NC) opens.
Figure 28c: AC Control Power (with Capacitor Trip).
18
Courtesy of NationalSwitchgear.com