Siemens 3AH3 User manual

Instruction manual
Types 3AH3 and 3AHc vacuum circuit breaker operator modules
4.16 kV to 38 kV
Installation operation maintenance E50001-F710-A251-V1-4A00
www.usa.siemens.com/mvswitchgear
Answers for infrastructure and cities.

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 obligation. 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 instruction manual a
qualified 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:
Is trained and authorized to
de-energize, clear, ground and tag
circuits and equipment in accordance
with established safety procedures.
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.
Is trained in rendering first aid.
Further, a qualified person shall also be
familiar with the proper use of special
precautionary techniques, personal
protective equipment, insulation and
shielding materials, and insulated tools and
test equipment. Such persons are permitted
to work within limited approach of exposed
live parts operating at 50 volts or more, and
shall, at a minimum, be additionally trained
in all of the following:
The skills and techniques necessary to
distinguish exposed energized parts from
other parts of electric equipment
The skills and techniques necessary to
determine the nominal voltage of
exposed live parts
The approach distances specified in NFPA
70E®and the corresponding voltages to
which the qualified person will be
exposed
The decision-making process necessary
to determine the degree and extent of
the hazard and the personal protective
equipment and job planning necessary to
perform the task safely.
Hazardous voltages and high-speed moving parts.
Will cause death, serious injury or property damage.
Always de-energize and ground the equipment before maintenance. Read
and understand this instruction manual before using equipment.
Maintenance should be performed only by qualified personnel. The use of
unauthorized parts in the repair of the equipment or tampering by
unqualified personnel will result in dangerous conditions which will cause
death, severe injury or equipment damage. Follow all safety instructions
contained herein.

Note:
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
that are not covered sufficiently for the
purchaser’s purposes, the matter should be
referred to the local sales office.
The contents of this instruction manual shall
not become part of or modify any prior or
existing agreement, commitment or
relationship. The sales contract contains the
entire obligation of Siemens Industry, Inc. The
warranty contained in the contract between
the parties is the sole warranty of Siemens
Industry, Inc. Any statements contained herein
do not create new warranties or modify the
existing warranty.
Table of contents
Introduction 04 – 05
Receiving, handling and storage 06 – 08
Installation checks and functional tests 09 – 10
Vacuum interrupter/operator 11 – 27
Maintenance 28 – 41
Overhaul 42 – 46
Technical data and troubleshooting 47 – 55

4
Signal words
The signal words “danger,” “warning” and
“caution” used in this manual indicate the
degree of hazard that may be encountered
by the user. These words are defined as:
Danger - Indicates an imminently hazardous
situation that, if not avoided, will result in
death or serious injury.
Warning - Indicates a potentially hazardous
situation that, if not avoided, could result in
death or serious injury.
Caution - Indicates a potentially hazardous
situation that, if not avoided, may result in
minor or moderate injury.
Caution (without safety alert symbol) -
Indicates a potentially hazardous situation
that, if not avoided, may result in property
damage.
Introduction
The type 3AH3 and type 3AH-compact
(3AHc) families of vacuum circuit breaker
operator modules are designed to meet all
applicable ANSI, NEMA and IEEE standards.
Successful application and operation of this
equipment depends as much upon proper
installation and maintenance by the user as
it does upon the proper 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.
In this instruction manual, reference to type
3AH includes both type 3AH3 and type 3AHc
operator modules. When information
specific to the type 3AH-compact (3AHc)
design is involved, the text will so designate.
Hazardous voltages and high speed moving parts.
Will cause death, serious injury or property damage.
Always de-energize and ground the equipment before maintenance.
Read and understand this instruction manual before using equipment.
Maintenance should be performed only by qualified personnel. The use
of unauthorized parts in the repair of the equipment or tampering by
unqualified personnel will result in dangerous conditions which will
cause death, severe injury or equipment damage. Follow all safety
instructions contained herein.
Introduction

5
Hazardous Procedures
In addition to other procedures described in
this instruction manual as dangerous, user
personnel must adhere to the following:
1. Always work only on a de-energized
circuit breaker. The circuit breaker should
be isolated, grounded and have all
control power removed before
performing any tests, maintenance or
repair.
2. Always perform maintenance on the
circuit breaker after the spring-charged
mechanisms are discharged (except for
test of the charging mechanisms). Check
to be certain that the indicator flags read
OPEN and DISCHARGED.
3. Always let an interlock device or safety
mechanism perform its function without
forcing or defeating the device.
Field service operation and warranty
issues
Siemens can provide competent, well-
trained field service representatives to
provide technical guidance and advisory
assistance for the installation, overhaul,
repair and maintenance of Siemens
equipment, processes and systems. Contact
regional service centers, sales offices or the
factory for details, or telephone Siemens
field service at 1-800-347-6659 or 1-919-
365-2200 outside the U.S.
For medium voltage customer service
issues, contact Siemens at 1-800-347-6659
or 1-919-365-2200 outside the U.S.

6
Introduction
This portion of the instruction manual
covers the receiving, handling and storage
instructions for a type 3AH3 vacuum circuit
breaker operator module. This section of the
instruction manual is intended to help the
user identify, inspect and protect the circuit
breaker operator module prior to its
installation.
Receiving procedure
Make a physical inspection of the shipping
container before removing or unpacking the
circuit breaker operator module.
Check for shipment damage or indications
of rough handling by the carrier. Check each
item against the manifest to identify any
shortages.
Accessories such as the manual charging
crank, the racking crank (if applicable) and
the split plug jumper (if applicable) are
shipped separately.
Shipping damage claims
Important: The manner in which visible
shipping damage is identified by consignee
prior to signing the delivery receipt can
determine the outcome of any damage
claim to be filed.
Notification to carrier within 15 days for
concealed damage is essential if loss
resulting from unsettled claims is to be
eliminated or minimized.
1. When the shipment arrives, note
whether the equipment is properly
protected from the elements. Note the
trailer number the equipment arrived on.
Note also any blocking of equipment.
During unloading, check the actual
equipment delivered to verify it agrees
with the delivery receipt.
2. Make immediate inspection for visible
damage upon arrival and prior to
disturbing or removing packaging or
wrapping material. This should be done
prior to unloading when possible. When
total inspection cannot be made on
vehicle prior to unloading, close
inspection during unloading must be
performed and visible damage noted on
the delivery receipt. Take pictures if
possible.
Heavy weight.
Improper lifting or hoisting can result in death, serious injury or
property damage.
Obtain the services of a qualified rigger prior to hoisting the circuit
breaker to assure adequate safety margins in the hoisting equipment
and procedures to avoid damage.
Receiving, handling
and storage

7
3. Any visible damage must be noted on the
delivery receipt and acknowledged with
the driver’s signature. The damage should
be detailed as much as possible. It is
essential that a notation "possible
internal damage, subject to inspection"
be included on the delivery receipt. If the
driver will not sign the delivery receipt
with the damage noted, the shipment
should not be signed for by the
consignee or their agent.
4. Notify Siemens medium-voltage
customer service immediately of any
damage, at 1-800-347-6659 or 1-919-
365-2200 outside the U.S.
5. Arrange for a carrier inspection of the
damage immediately.
Important: Do not move the equipment
from the place it was set when unloading.
Also, do not remove or disturb packaging or
wrapping material prior to carrier damage
inspection. Equipment must be inspected by
carrier prior to handling after receipt. This
eliminates loss due to claims by carrier that
the equipment was damaged or further
damaged on site after unloading.
6. Be sure the equipment is properly
protected from any further damage by
covering it properly after unloading.
7. If practical, make further inspection for
possible concealed damage while the
carrier’s inspector is on site. If inspection
for concealed damage is not practical at
the time the carrier’s inspector is
present, it must be done within 15 days
of receipt of the equipment. If concealed
damage is found, the carrier must again
be notified and inspection made prior to
taking any corrective action to repair.
Also notify Siemens immediately at
1-800-347-6659 or 1-919-365-2200
outside the U.S.
8. Obtain the original carrier inspection
report and forward it with a copy of the
noted delivery receipt to Siemens.
Approval must be obtained by Siemens
from the carrier before any repair work
can be performed.
Before approval can be obtained, Siemens
must have the documents referenced in
the paragraph above. The carrier
inspection report and/or driver’s signature
on the delivery receipt does not constitute
approval to repair.
Note: Shipments are not released from the
factory without a clear bill of lading.
Approved methods are employed for
preparation, loading, blocking and tarping
of the equipment before it leaves the
Siemens factory. Any determination as to
whether the equipment was properly loaded
or properly prepared by shipper for over-the-
road travel cannot be made at the
destination. If the equipment is received in a
damaged condition, this damage to the
equipment has to have occurred while en
route due to conditions beyond Siemens‘
control. If the procedure outlined above is
not followed by the consignee, purchaser or
their agent, Siemens cannot be held liable
for repairs. Siemens will not be held liable
for repairs in any case where repair work
was performed prior to authorization from
Siemens.
Handling procedure
1. Carefully remove the shipping carton
from the circuit breaker. Keep the
shipping pallet for later use if the circuit
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
claim resolution.
3. Each circuit breaker should be lifted
appropriately to avoid crushing the side
panels of the circuit breaker, or
damaging the primary disconnect
assemblies.
Type 3AH3 vacuum circuit breaker
operator modules weigh between 165
and 408 lbs (75-185 kg), plus an
additional 100 lbs (45 kg) for packaging
and pallet. Refer to Table 13 for more
information.
Type 3AHc vacuum circuit breaker
operator modules are not furnished
separately, but are supplied as a
component of a complete drawout
circuit breaker. Weights and lifting
details are provided in the circuit breaker
manuals.
4. The palleted circuit breaker can be
moved using a properly rated fork-lift
vehicle. The pallets are designed for
movement by a standard fork-lift vehicle.

8
C
A
B
Item Description Item Description
AManual spring-charging port EManual close pushbutton
BCHARGED/DISCHARGED indicator FManual open pushbutton
COPEN/CLOSED indicator GRating plate
DOperation counter
D
E
F
Storage procedure
1. Whenever possible, install the circuit
breaker operator module in its assigned
switchgear enclosure or end location for
storage.
2. When the circuit breaker operator
module needs to be placed on its pallet
for storage, be sure the unit is securely
bolted to the pallet and covered with
polyethylene film at least 10 mils thick.
Indoor storage
Whenever possible, store the circuit breaker
operator module indoors. The storage
environment must be clean, dry and free of
such items as construction dust, corrosive
atmosphere, mechanical abuse and rapid
temperature variations.
Outdoor storage
Outdoor storage is not recommended. When
no other option is available, the circuit
breaker operator module must be
completely covered and protected from rain,
snow, dirt and all other contaminants.
Space heating
Space heating must be used for both indoor
and outdoor storage to prevent
condensation and corrosion. When the
circuit breaker operator module is stored
outdoors, 250 watts per circuit breaker of
space heating is recommended. If the circuit
breaker operator module is stored inside the
switchgear enclosure, and the switchgear is
equipped with space heaters, energize the
space heaters.
Figure 1: Front panel controls of circuit breaker and manual charging of closing spring

9
Introduction
This section provides a description of the
inspections, checks and tests to be
performed on the circuit breaker operator
module only.
Inspections, checks and tests without
control power
Vacuum circuit breakers are normally
shipped with their primary contacts OPEN
and their springs DISCHARGED. However, it
is critical to first verify the DISCHARGED
condition of the spring-loaded mechanisms
after de-energizing control power.
De-energizing control power in
switchgear
When the circuit breaker is mounted in
switchgear, open the control-power
disconnect device in the metal-clad
switchgear cubicle, outdoor circuit breaker
housing or other location.
In metal-clad switchgear, the control-power
disconnect device is normally located on the
secondary-device panel in the upper cell of
the vertical section. The normal control-
power disconnect device is a pullout-type
fuse holder. Removal of the fuse holder
de-energizes control power to the circuit
breaker in the associated switchgear cell.
In some switchgear assemblies, a molded-
case circuit breaker or knife switch is used in
lieu of the pullout-type fuse holder. Opening
this circuit breaker or switch accomplishes
the same result: control power is
disconnected. Opening this circuit breaker
or switch accomplishes the same result:
control power is disconnected.
Hazardous voltage and high-speed moving parts.
Will cause death, serious injury and property damage.
Read instruction manuals, observe safety instructions and use qualified
personnel.
Installation checks
and functional tests

10
Automatic spring-charging check
The automatic spring-charging features of
the circuit breaker must be checked. Control
power is required for automatic spring-
charging to take place.
Note: A temporary source of control power
and test leads may be required if the
control-power source has not been
connected to the switchgear or circuit
breaker. Refer to specific wiring information
and rating label for your circuit breaker to
determine the voltage required and where
the control-voltage signal should be applied.
When control power is connected to the
circuit breaker, the closing spring should
automatically charge.
1. Open control-power circuit by opening
the control-power disconnect device.
2. Energize (close) the control power-circuit
disconnect.
3. Use the close and open controls (refer to
Figure 1) to first close and then open the
circuit breaker contacts. Verify contact
positions visually by observing the OPEN/
CLOSED indicator on the circuit breaker.
4. De-energize (close) the control-power by
repeating Step 1. If a split-plug jumper
was used for temporary control-power
connections, disconnect the split-plug
jumper from the switchgear first and
next from the circuit breaker.
5. Perform the spring discharge check
again. Verify the closing springs are
DISCHARGED and the primary contacts of
the circuit breaker are OPEN.
Final mechanical inspections without
control power
1. Make a final mechanical inspection of
the circuit breaker. Verify the contacts
are in the OPEN position, and the closing
springs are DISCHARGED.
2. Verify mechanical condition of springs.
3. Check for loose hardware.
Spring-discharge check (refer to Figure 1)
Perform the spring-discharge check before
removing the circuit breaker or operator
module from the pallet or removing it from
the switchgear.
The spring-discharge check should be
performed after de-energizing control
power. This check assures both the tripping
and closing springs are fully discharged.
Note: Do not perform the spring-discharge
check if the circuit breaker is in the
CONNECT position. Open the circuit breaker
and rack to the DISCONNECT position, and
then perform the spring-discharge check.
For fixed-mounted circuit breaker
applications, open the isolator switches on
the line side and on the load side of the
circuit breaker before performing the spring-
discharge check.
1. Press red trip pushbutton.
2. Press black close pushbutton.
3. Press red trip pushbutton again.
4. Verify spring-condition indicator shows
DISCHARGED.
5. Verify main contact status indicator
shows OPEN.
Manual-spring charging check
1. Insert the manual-spring charging crank
into the manual-charge handle socket as
shown in Figure 1. Turn the crank
clockwise (about 48 revolutions) until
the spring condition indicator shows the
closing spring is CHARGED.
2. Repeat the spring-discharge check.
3. Verify the springs are DISCHARGED and
the circuit-breaker primary contacts are
OPEN by indicator positions.
As-found and vacuum-integrity check
tests
Perform and record the results of both the
as-found insulation test and the vacuum-
integrity check (dielectric) test. Procedures
for these tests are described in the
Maintenance section of this instruction
manual beginning on page 28.

11
Vacuum interrupter/
operator
Introduction
The type 3AH vacuum circuit-breaker
operator is intended for application in a
drawout truck for use in medium-voltage
metal-clad switchgear and for stationary
applications, such as the type SDV6 outdoor
distribution circuit breaker. The type 3AH
circuit breaker conforms to the requirements
of ANSI/IEEE standards, including C37.20.2,
C37.04, C37.06, C37.09 and C37.010.
Figure 2: Vacuum circuit breaker operator module
Item Description Item Description
APole head LGuide link
BUpper connection pad MUpper post insulator
CStrut NOperator housing
DVacuum interrupter OLower post insulator
EMoving contact PInsulating coupler (48.0)
FCentering piece QContact pressure spring (49.0)
GTerminal clamp RLever
HFlexible connector SJack shaft
IEye bolt TPole plate
JPole bottom (lower pole head) ULower connector
KAngled lever VVehicle frame
C
A
B
E
D
F
G
H
I
J
L
O
P
Q
S
R
M
K
N
3AH vacuum circuit breaker operator 3AHc vacuum
circuit breaker
operator
TN
P
Q
A
B
CD
J
O
M
U
V
H
K
G
F
E
S
R
J

12
Figure 3: Vacuum interrupter cut-
away view
Item Description
1Fixed contact-current
connection
2 Ceramic insulator
3 Arc shield
4 Fixed contact
5 Moving contact
6 Ceramic insulator
7 Metal bellows
8 Guide
9Moving contact-
current connection
1
2
3
4
5
6
8
9
7
Figure 4: Vacuum circuit breaker operator module
The circuit breaker includes three vacuum
interrupters, a stored-energy operating
mechanism, necessary electrical controls
and interlock devices, disconnect devices to
connect the circuit breaker to both primary
and control power (for drawout
applications) and an operator housing.
In a typical installation in a drawout truck,
insulating barriers may be located between
the vacuum interrupters and along the
sides.
3AH vacuum circuit breaker operator
3AHc vacuum circuit breaker operator
This section describes the operation of each
major subassembly as an aid in the
operation, installation, maintenance and
repair of the circuit breaker.
Vacuum interrupters
The operating principle of the vacuum
interrupter is simple. Figure 3 is a section
view of a typical vacuum interrupter. The
entire assembly is sealed after a vacuum is
established.
3AH3 operator mechanism
The vacuum interrupter stationary contact is
connected to the upper pole head of the
circuit breaker. The vacuum interrupter
movable contact is connected to the pole
bottom and driving mechanism of the circuit
breaker.
3AHc operator mechanism
The vacuum interrupter stationary contact is
connected to the lower pole head of the
circuit breaker. The vacuum interrupter
movable contact is connected to the upper
pole head (pole bottom) and drive
mechanism of the circuit breaker.
The metal bellows provide a secure seal
around the movable contact, preventing loss
of vacuum while permitting vertical motion
of the movable contact.
When the two contacts separate, an arc is
initiated that continues conduction up to
the following current zero. At current zero,
the arc extinguishes and any conductive
metal vapor that has been created by and
supported the arc condenses on the
contacts and on the surrounding arc shield.
Contact materials and configuration are
optimized to achieve arc motion and to
minimize switching disturbances.
Primary connections (refer to Figure 2)
Figure 2 illustrates the pad provision to
accept the primary connections. Each circuit
breaker has three upper and three lower
primary disconnect pad provisions, to allow
connection to the switchgear.
For stationary circuit breaker applications,
bus conductors connect directly to these
pads. Bolting hardware is M12 x 1.75 grade
8. Torque M12 bolts to 52 ft-lb (70 Nm).

13
Phase barriers (if applicable)
Plates of glass-polyester insulating material
are attached to the circuit breaker and
provide suitable electrical insulation
between the vacuum interrupter and
primary conductors and the cubicle.
Stored-energy operating mechanism
The stored-energy operating mechanism of
the circuit breaker is an integrated
arrangement of springs, coils and
mechanical devices designed to provide a
number of critical functions. The energy
necessary to close and open the contacts of
the vacuum interrupters is stored in
powerful opening and closing springs. The
closing springs are normally charged
automatically, but there are provisions for
manual charging. The operating mechanism
that controls charging, closing and tripping
functions is fully trip-free. “Trip-free”
requires that the tripping function prevail
over the closing function as specified in
ANSI/IEEE C37.04-1999, clause 6.9.
Vacuum interrupter/operator module
The vacuum interrupter/operator module
consists of the three poles, each with its
vacuum interrupters and primary insulators,
mounted on the common operating
mechanism housing. This module is shown
in Figure 4.
Construction (Refer to Figures 1, 2, 5 and
6) (3AH only)
This description covers the type 3AH
operator. The type 3AHc differs in
arrangement but the fundamental
discussion of operation applies.
Each of the circuit breaker poles are fixed to
the rear of the operating mechanism
housing by two cast-resin insulators. The
insulators also connect to the upper and
lower pole supports that in turn support the
ends of the vacuum interrupter.
The pole supports are aluminum castings
(most 1,200 A, all 2,000 A and some
3,000 A), copper castings (some 3,000 A) or
sheet steel (some 1,200 A). For type 3AH
operators, primary disconnect stud
extensions may be attached directly to the
upper and lower pole connection pads.
The energy-storing mechanism and all the
control and actuating devices are installed
in the operator housing. The mechanism is
of the spring stored-energy type and is
mechanically and electrically trip-free.
The close-open indicator, closing spring-
charge indicator and the operation counter
are located on the front of the operator
housing.
The control connector for the control and
signalling cables is a multi-contact plug in
most designs, although direct connection to
the switchgear is used for certain products.
Circuit breaker pole (refer to Figure 2)
The vacuum interrupter is bolted to the
upper pole head and the upper pole head is
rigidly connected to the operator housing by
the post insulator. The moving contact end
of the vacuum interrupter is stabilized
against lateral forces by a centering ring on
the pole bottom. The external forces due to
switching operations and the contact
pressure are absorbed by the struts.
Current-path assembly (refer to Figure 2)
The current-path assembly consists of the
pole head, the stationary contact and the
moving contact, that is connected to the
pole bottom by a terminal clamp and a
flexible connector.
Vacuum interrupter (refer to Figure 2)
The moving-contact motion is aligned and
stabilized by a guide bushing. The metal
bellows follows the travel of the contact and
seals the vacuum interrupter against the
surrounding atmosphere.
Switching operation (refer to Figures 2
and 5)
When a closing command is initiated, the
closing spring (62.0), that was previously
charged by hand or by the motor, actuates
the moving contact through the jack shaft
(63.0), lever, contact pressure spring (49.0),
insulating coupler (48.0) and angled lever.
The forces that occur when the action of the
insulating coupler (48.0) is converted into
the vertical action of the moving contact are
absorbed by the guide link, that pivots on
the pole bottom and the eye bolt.

14
During closing, the opening spring (64.0)
(refer to Figure 6) and the contact pressure
springs (49.0) are charged and latched by
pawl (64.2) (refer to Figure 6). The closing
spring (62.0) (refer to Figure 5) of the
motor-operated circuit breaker is recharged
immediately after closing.
In the closed state, the necessary contact
pressure is maintained by the contact
pressure springs (49.0) and the atmospheric
pressure. The contact pressure spring
automatically compensates for arc erosion,
which is very small.
When a opening command is given, the
energy stored in the opening and contact
pressure springs (49.0) is released by pawl
(64.2) (refer to Figure 6).
The opening sequence is similar to the
closing sequence. The residual force of the
opening spring maintains the moving
contacts in the open position.
Operating mechanism
The operating mechanism is comprised of
the mechanical and electrical components
required to:
1. Charge the closing spring with sufficient
potential energy to close the circuit
breaker and to store opening energy in
the opening and contact pressure
springs.
2. Mechanisms to release closing and
opening actions.
3. Means of transmitting force and motion
to each of the three vacuum
interrupters.
4. Operate all these functions
automatically through an electrical
charging motor, cutout switches, an
anti-pump relay, a close coil, an open
coil and an auxiliary switch.
5. Provide indication of the circuit breaker
status (OPEN/CLOSED), spring condition
(CHARGED/DISCHARGED) and number of
operations.
Construction
The essential parts of the operating
mechanism are shown in Figures 5 and 6.
The control and sequence of operation of
the mechanism is described in Figure 7.
Motor-operating mechanism (refer to
Figure 5)
The spring-charging motor (50.4) is bolted
to the charging mechanism (50.2) gear box
installed in the operator housing. Neither
the charging mechanism nor the motor
require any maintenance.
Mode of operation
The operating mechanism is of the stored-
energy trip-free type. For example, the
charging of the closing spring is not
automatically followed by the contacts
changing position, and tripping function
prevails over the closing function.
When the stored-energy mechanism has
been charged, the mechanism is ready for a
closing operation at any time.
The mechanical energy for carrying out an
“Open-Close-Open” sequence for auto-
reclosing duty is stored in the closing and
opening springs.
Charging
The details of the closing spring charging
mechanism are shown in Figure 5. The
charging shaft is supported in the charging
mechanism gear box (50.2), but is not
coupled mechanically with the charging
mechanism. Fitted to it are the crank (62.2)
at one end, and the cam (62.3), together
with lever (62.5), at the other.

15
Figure 5: Stored-energy operating mechanism (circuit breaker shown in OPEN position) (straight linkage shown)
Item Description Item Description
50.2 Charging mechanism gear box 62.1 Charging shaft
50.3 Charging flange 62.2 Crank
50.3.1 Driver (not visible) 62.3 Cam disc
50.4 Spring charging motor 88.0 62.5 Lever
50.4.1 Limit switches 62.5.1 Pawl roller (not visible)
50.5 Manual spring-charging port 62.5.2 Close latch pawl
53.0 Close pushbutton 62.6 Driver lever
53.1 Close coil 52SRC 62.8 Straight coupling rod1
54.0 Open pushbutton 62.8.1 Spring return latch (not shown)1
54.1 Trip coil 52T 62.8.3 Trip-free coupling lever1
55.0 Closing spring-charge indicator 63.0 Jack shaft
55.1 Linkage 63.1 Lever phase C
55.2 Control lever 63.5 Lever phase B
58.0 CLOSED/OPEN indicator 63.7 Lever phase A
59.0 Operations counter 64.0 Opening spring
60.0 Operator housing 68.0 Auxiliary switch
61.8 Shock absorber 68.1 Auxiliary switch link
62.0 Closing spring
50.2
Footnote:
1. For certain applications, the
straight trip coupling rod (62.8) is
replaced by a collapsible trip-free
coupling system, illustrated in
Figures 6-10.
50.5
55.2
50.3
62.6
62.3
62.5
68.0
62.5.2
53.0
53.1
54.1
54.0
68.1
63.163.0
63.5
61.8
60.0
59.0
58.0
64.0
50.4
55.0
50.4.1
62.0
55.1
62.2
62.1

16
When the charging mechanism is actuated
by hand with a hand crank (refer to Figures
12 and 13) or by a motor (50.4), the flange
(50.3) turns until the driver (50.3.1) locates
itself in the cutaway part of the cam disc
(62.3), thus causing the charging shaft to
follow. The crank (62.2) charges the closing
spring (62.0). When the closing spring has
been fully charged, the crank actuates the
linkage (55.1) via the control lever (55.2)
for the closing spring CHARGED indicator
(55.0), and actuates the limit switches
(50.4.1) for interrupting the motor supply.
At the same time, the lever (62.5) at the
other end of the charging shaft is securely
locked by the close latch pawl (62.5.2).
When the closing spring is being charged,
the cam disc (62.3) follows along, and it is
brought into position for closing when the
closing spring is fully charged.
Closing (refer to Figures 5, 7-10)
If the circuit breaker is to be closed
manually, the closing spring is released by
pressing the Close button (53.0). In the case
of remote electrical control, the close coil
52SRC (53.1) unlatches the closing spring
(62.0).
As the closing spring discharges, the
charging shaft (62.1) is turned by crank
(62.2).
The cam disc (62.3) at the other end of the
charging shaft actuates the drive lever
(62.6), with the result that jack shaft (63.0)
is turned by lever (63.5) via the coupling rod
(62.8). At the same time, the levers (63.1),
(63.5) and (63.7) fixed on the jack shaft
operate the three insulated couplers (48.0)
(refer to Figure 2) for the circuit breaker
poles. Lever (63.7) changes the OPEN/CLOSE
indicator (58.0) over to CLOSED. Lever
(63.5) charges the opening spring (64.0)
during closing, and the circuit breaker is
latched in the closed position by lever (64.3)
with pawl roller (64.3.1) and by pawl (64.2).
Lever (63.1) actuates the auxiliary switch
(68.0) through the linkage (68.1).
The crank (62.2) on the charging shaft
(62.1) moves the linkage (55.1) by acting
on the control lever (55.2). The closing
spring charged indication is thus canceled,
and the limit switches (50.4.1) switch in the
control supply to cause the closing spring to
recharge immediately.
Trip-free operation
(refer to Figures 5 and 6)
Trip-free for all drawout circuit breakers
and some fixed-mounted circuit breakers
The trip coupling rod (62.8 together with
62.8.1 and 62.8.2) permits the immediate
de-coupling of the drive lever (62.6) and the
jack shaft (63.0) to override closing action
by trip command or by means of the racking
interlocks.
The trip-free coupling rod (62.8) forms a
link between the drive lever (62.6) and the
jack shaft (63.0). The rigidity of this link
depends upon a spring-return latch (62.8.1)
carried within the coupling rod. The latch
pivots within the coupling rod and is
normally positioned to maintain the rigidity
of the coupling rod.
Figure 6: Stored-energy operating mechanism (circuit breaker shown in CLOSED position)
(Drawout trip-free linkage shown)
Item Description
54.0 Open pushbutton
62.8 Trip-free coupling rod1
62.8.1 Spring-return latch1
62.8.2 Trip-free coupling link
(draw bar)1
64.0 Opening spring
64.2 Trip-latch pawl (not visible)
64.3 Lever
64.3.1 Pawl roller 64.3.1
62.8
Footnote:
1. For type SDV6 and some fixed-mounted circuit breakers, trip-free coupling rod (62.8) is
replaced with a straight coupling rod, and other parts associated with drawout
interlocking are eliminated.
54.0
64.3
62.8.2
62.8.1
64.0

17
Trip-free coupling link (62.8.2) and trip-free
coupling lever (62.8.3) cause the spring-
return latch position to be dependent upon
the normal tripping components and the
racking interlock (if applicable). Thus,
whenever a trip command is applied or the
circuit breaker is not in the fully CONNECT
or TEST position (for drawout applications),
the trip-free coupling rod is no longer rigid,
effectively decoupling the drive lever and
jack shaft. Under these conditions the
vacuum interrupter contacts cannot be
closed.
Trip-free for the type SDV6 outdoor distri-
bution circuit breaker and some fixed-
mounted circuit breakers
For the type SDV6 outdoor distribution
circuit breaker and some other fixed-
mounted circuit breakers, the drawout trip-
free linkage (refer to Figures 7-10) is
replaced with simplified linkage. The trip-
free coupling rod (62.8) is replaced with a
straight coupling rod (refer to Figure 5), and
other parts associated with drawout
interlocking are eliminated.
The parts modified or eliminated are noted
in the relevant figures. In these circuit
breakers, the trip-free function is
accomplished by blocking the movement of
the close latch pawl (62.5.2) when the
manual trip pushbutton is actuated.
Opening (refer to Figure 5)
If the circuit breaker is to be opened
manually, the opening spring (64.0) is
released by pressing the OPEN pushbutton
(54.0). In the case of an electrical command
being given, the trip coil 52T (54.1)
unlatches the opening spring (64.0).
The opening spring (64.0) turns the jack
shaft (63.0) via lever (63.5); the sequence
being similar to that for closing.
Rapid auto-reclosing
Since the closing spring is automatically
recharged by the motor operating
mechanism when the circuit breaker has
closed, the operating mechanism is capable
of an “Open-Close-Open” duty cycle as
required for rapid auto-reclosing.
The circuit breaker is suitable for use in
applications with a rated reclosing-time
interval of 0.3 seconds, per ANSI/IEEE
C37.06-2009.
Manual operation
Electrically operated vacuum circuit breakers
can be operated manually if the control
supply should fail.
Manually charging the closing spring
(refer to Figures 13 and 14)
Insert the hand crank (50.0) with the over
running coupling pushed forward (50.6)
through the opening (50.1) onto hand crank
coupling (50.5) and turn it clockwise (about
48 revolutions) until the closing-spring
indicator (55.0) shows CHARGED. The hand
crank is coupled with the charging
mechanism via an over-running coupling;
thus the operator is not exposed to any risk
should the control supply be restored during
manual charging.
The special hand crank automatically disengages
if the spring-charging motor operates. In order to
avoid injuries as a result of the motor suddenly
starting up, the circuit breaker spring must only
be charged manually with the special hand crank
(50.0).
Manual closing (refer to Figure 6)
Press the close button (53.0). The CLOSE/
OPEN indicator (58.0) will then display
CLOSED and the closing spring condition
indicator (55.0) will now read DISCHARGED.
Manual opening (refer to Figure 6)
The opening spring (64.0) is charged during
closing. To open the circuit breaker, press
the Open pushbutton (54.0) and OPEN will
be displayed by indicator (58.0).

18
Figure 7: Operating mechanism section diagram (drawout trip-free linkage shown) mechanism OPEN, closing spring DISCHARGED
Item Description
48.0 Insulating coupler
50.3 Charging flange
50.3.1 Driver
53.0 Close pushbutton
53.1 Close coil 52SRC
54.0 Open pushbutton
54.1 Trip coil 52T
62.1 Charging shaft
62.2 Crank
62.2.2 Closing-spring mounting
62.3 Cam disc
62.5 Lever
62.5.1 Pawl roller
62.5.2 Close latch pawl
62.6 Drive lever
62.8 Trip-free coupling rod
62.8.1 Spring-return latch
62.8.2 Trip-free coupling link (draw bar)
62.8.3 Trip-free coupling lever
62.8.5 Push rod and cam assembly
62.8.6 Interlock lever push rod
62.8.7 Interlock lever actuator
62.8.8 Trip-free actuator
63.0 Jack shaft
63.1 Lever - phase C
63.5 Lever - phase B
63.7 Lever - phase A
64.0 Opening spring
64.2 Trip-latch pawl
64.2.1 Trip-latch pin
64.2.2 Latching pawl-release lever
64.3 Lever
64.3.1 Jack-shaft pawl
64.5 Opening-spring shaft
62.5
62.1
62.3†
62.2†
62.6
53.0
50.3
53.1
54.0
62.8*
64.5*
48.0*
64.2*
63.5*
63.0*
64.0*
64.5*
63.5* 63.7
63.1
63.5
62.8.2†
62.8.7†
62.8.6†
62.8.8
62.8.1
62.5.1†
62.5.2†
50.3.1
62.2.2
64.2.2
64.2.1†
62.8.3†
64.3.1*
62.8.5†
Footnotes:
* Items moved from position shown in Figure 9: Operating mechanism section diagram (drawout trip-free linkage shown) mechanism
CLOSED, closing spring DISCHARGED on trip operation.
† Items moved from position shown in Figure 8: Operating mechanism section diagram (drawout trip-free linkage shown) mechanism OPEN,
closing spring DISCHARGED on closed spring discharge operation.
1. For type SDV6 and some fixed-mounted circuit breakers, trip-free coupling rod (62.8) is replaced with a straight coupling rod, and other
parts associated with drawout interlocking are eliminated.

19
Figure 8: Operating mechanism section diagram (drawout trip-free linkage shown) mechanism OPEN, closing spring DISCHARGED
.
Item Description
48.0 Insulating coupler
50.3 Charging flange
50.3.1 Driver
53.0 Close pushbutton
53.1 Close coil 52SRC
54.0 Open pushbutton
54.1 Trip coil 52T
62.1 Charging shaft
62.2 Crank
62.2.2 Closing-spring mounting
62.3 Cam disc
62.5 Lever
62.5.1 Pawl roller
62.5.2 Close latch pawl
62.6 Drive lever
62.8 Trip-free coupling rod
62.8.1 Spring-return latch
62.8.2 Trip-free coupling link (draw bar)
62.8.3 Trip-free coupling lever
62.8.5 Push rod and cam assembly
62.8.6 Interlock lever push rod
62.8.7 Interlock lever actuator
62.8.8 Trip-free actuator
63.0 Jack shaft
63.1 Lever - phase C
63.5 Lever - phase B
63.7 Lever - phase A
64.0 Opening spring
64.2 Trip-latch pawl
64.2.1 Trip-latch pin
64.2.2 Latching pawl-release lever
64.3 Lever
64.3.1 Jack-shaft pawl
64.5 Opening-spring shaft
Footnotes:
* Items moved from position shown in Figure 10: Operating mechanism section diagram (drawout trip-free linkage shown) mechanism
CLOSED, closing spring CHARGED on trip operation.
†Items moved from position shown in Figure 7: Operating mechanism section diagram (drawout trip-free linkage shown) mechanism
OPEN, closing spring DISCHARGED on closed spring discharge operation.
1. For type SDV6 and some fixed-mounted circuit breakers, trip-free coupling rod (62.8) is replaced with a straight coupling rod, and other
parts associated with drawout interlocking are eliminated.
62.5†
62.1†62.3†
62.2†
63.0*
50.3†
54.1*
64.5*
48.0*
62.8*
63.5*
64.3*
64.5*
63.5* 63.7*
63.1*
63.5*
62.5.1†
50.3.1†
62.2.2†
64.2*

20
Figure 9: Operating mechanism section diagram (drawout trip-free linkage shown) mechanism CLOSED, closing spring DISCHARGED
Footnotes:
* Numbered items moved from position shown in Figure 8: Operating mechanism section diagram (drawout trip-free linkage shown)
mechanism OPEN, closing spring DISCHARGED.
1. For type SDV6 and some fixed-mounted circuit breakers, trip-free coupling rod (62.8) is replaced with a straight coupling rod, and other
parts associated with drawout interlocking are eliminated.
Item Description
48.0 Insulating coupler
53.0 Close pushbutton
53.1 Close coil 52SRC
62.1 Charging shaft
62.2 Crank
62.2.2 Closing-spring mounting
62.3 Cam disc
62.5 Lever
62.5.1 Pawl roller
62.5.2 Close latch pawl
62.6 Driver lever
62.8 Trip-free coupling rod
63.0 Jack shaft
63.1 Lever - phase C
63.5 Lever - phase B
63.7 Lever - phase A
64.5 Opening-spring shaft
62.5
62.1
62.3
62.2
62.6
53.0
53.1
62.8
64.5
48.0 63.5
63.0
64.5
63.7
63.1
63.5
62.5.1
62.5.2
62.2.2