Powell PowlVac IB-60201 User manual

IB-60201 PowlVac®STD
Vacuum Circuit Breaker
5kV & 15kV
1200A, 2000A, & 3000A
Powered by Safety®
Courtesy of NationalSwitchgear.com

Powered by Safety®
PowlVac®STD Vacuum Circuit Breaker
IB-60201
Contact Information
Powell Electrical Systems, Inc.
www.powellind.com
[e-mail]
Service Division
PO Box 12818
Houston, Texas 77217-2818
Tel: [phone]
Fax: [phone]
Courtesy of NationalSwitchgear.com

Powered by Safety®
IB-60201
Signal Words
As stated in ANSI Z535.4-2002, § 4.13-4.13.3 the
signal word is a word that calls attention to the
safety sign and designates a degree or level of
hazard seriousness. The signal words for product
safety signs are “Danger”, “Warning”, and
“Caution”. These words are defined as:
DANGER indicates an imminently hazardous
situation which, if not avoided, will result in
death or serious injury.
DANGERDANGER
!
WARNING indicates a potentially hazardous
situation which, if not avoided, could result in
death or serious injury.
WARNINGWARNING
!
CAUTIONCAUTION
!
CAUTION indicates a potentially hazardous
situation which, if not avoided, may result in
minor or moderate injury.
Not stated in ANSI Z535.4-2002, § 4.13-4.13.3
as a signal word but used in this manual is
“IMPORTANT”. This is defined as:
IMPORTANT indicates a section of the manual
covering a non hazardous situation, but
one where Powell feels proper attention is
warranted.
IMPORTANTIMPORTANT
!
Qualified Person
For the purposes of this manual, a qualified person,
as stated in NFPA 70®, is one familiar with the
construction and operation of the equipment and
the hazards involved.
In addition to the above qualifications, one must
also be:
1. trained and authorized to energize,
deenergize, clear, ground, and tag circuits
and equipment in accordance with
established safety practices.
2. trained in the proper care and use of
personal protective equipment (PPE)
such as rubber gloves, hard hat, safety
glasses or face shields, flash clothing, etc.,
in accordance with established safety
practices.
3. trained in rendering first aid if necessary.
Courtesy of NationalSwitchgear.com

Powered by Safety®
PowlVac®STD Vacuum Circuit Breaker
IB-60201
This page is intentionally left blank.
Courtesy of NationalSwitchgear.com

Powered by Safety®i
IB-60201
Contents
Ch 1 General Information.................................................................................................1
A. Sc o p e ................................................................................................................................................................2
B. pu r p o S e .............................................................................................................................................................2
c. In S t r u c t I o n Bu l l e t I n S Av A I l A B l e el e c t r o n I c A l l y .....................................................................................................2
Ch 2 Safety ........................................................................................................................3
A. SA f e Wo r k co n d I t I o n .........................................................................................................................................3
B. SA f e t y Gu I d e l I n e S ...............................................................................................................................................3
c. Ge n e r A l .............................................................................................................................................................4
d. Sp e c I f I c ..............................................................................................................................................................4
e. X-rA y S ..............................................................................................................................................................5
f. SA f e t y lA B e l S .....................................................................................................................................................5
Ch 3 Equipment Description.............................................................................................6
A. Ge n e r A l .............................................................................................................................................................6
B. th e St o r e d e n e r G y Me c h A n I S M .............................................................................................................................6
1) Mechanical Description.......................................................................................................................................................... 6
2) Electrical Description.............................................................................................................................................................16
c. rA c k I n G Me c h A n I S M ......................................................................................................................................... 17
1) General Description...............................................................................................................................................................17
2) Standard Racking Mechanism............................................................................................................................................19
d. cI r c u I t Br e A k e r co M p A r t M e n t In t e r f A c e S ........................................................................................................... 19
1) Primary Disconnecting Devices..........................................................................................................................................19
2) Secondary Disconnecting Devices.....................................................................................................................................19
3) MOC (Mechanism Operated Cell Switch) Actuator........................................................................................................19
4) TOC (Truck Operated Cell Switch) Actuator.....................................................................................................................20
5) Ground Connection ...............................................................................................................................................................20
6) Shutter Rollers.........................................................................................................................................................................20
7) Anti-Rollout Latch..................................................................................................................................................................20
e. vA c u u M In t e r r u p t e r S ....................................................................................................................................... 20
f. vA c u u M In t e r r u p t e r co n n e c t I o n ....................................................................................................................... 20
Courtesy of NationalSwitchgear.com

Powered by Safety®
ii
PowlVac®STD Vacuum Circuit Breaker
IB-60201
Contents
Ch 4 Installation..............................................................................................................21
A. re c e I v I n G ........................................................................................................................................................ 21
B. hA n d l I n G ........................................................................................................................................................ 21
c. St o r A G e .......................................................................................................................................................... 22
d. pl A c I n G t h e cI r c u I t Br e A k e r In t o Se r v I c e ............................................................................................................ 23
1) High Voltage Insulation Integrity .......................................................................................................................................23
2) Vacuum Integrity....................................................................................................................................................................24
3) Control Voltage Insulation Integrity..................................................................................................................................25
4) Mechanical Operation Check..............................................................................................................................................26
5) Electrical Operation Check...................................................................................................................................................26
6) Racking Mechanism Check..................................................................................................................................................27
e. In S e r t I n G th e cI r c u I t Br e A k e r In t o th e cI r c u I t Br e A k e r co M p A r t M e n t .................................................................. 28
1) Prior to Inserting the Circuit Breaker into the Circuit Breaker Compartment..........................................................29
2) Inserting the Circuit Breaker to the Test/Disconnected Position.................................................................................30
3) Inserting the Circuit Breaker to the Connected Position...............................................................................................31
f. re M o v I n G t h e cI r c u I t Br e A k e r f r o M t h e cI r c u I t Br e A k e r co M p A r t M e n t .................................................................. 33
1) Removing the Circuit Breaker from the Connected to the Test/Disconnected Position........................................33
2) Removing the Circuit Breaker from the Test/Disconnected Position out of the Circuit Breaker
Compartment .........................................................................................................................................................................33
G. In S e r t I n G t h e cI r c u I t Br e A k e r uS I n G th r o u G h do o r rA c k I n G op t I o n ..................................................................... 34
1) Inserting the Circuit Breaker to the Test/Disconnect Position .....................................................................................34
2) Inserting the Circuit Breaker to the Connected Position...............................................................................................34
h. re M o v I n G t h e cI r c u I t Br e A k e r uS I n G th r o u G h do o r op t I o n ................................................................................ 37
1) Removing the Circuit Breaker from the Connected to the Test/Disconnected Position........................................37
2) Removing the Circuit Breaker from the Test/Disconnected Position out of the Circuit Breaker
Compartment .........................................................................................................................................................................38
3) Power Racking ........................................................................................................................................................................38
Courtesy of NationalSwitchgear.com

Powered by Safety®iii
IB-60201
Contents
Ch 5 Maintenance...........................................................................................................39
A. Ge n e r A l de S c r I p t I o n ........................................................................................................................................ 39
1) Introduction.............................................................................................................................................................................39
2) Inspection and Cleaning ......................................................................................................................................................40
B. Me c h A n I S M Ar e A ............................................................................................................................................. 40
1) Mechanical Operation ..........................................................................................................................................................40
2) Lubrication...............................................................................................................................................................................44
3) Closing Spring Removal........................................................................................................................................................44
4) Slow Closing of Mechanism.................................................................................................................................................45
5) Mechanism Adjustments......................................................................................................................................................46
6) Electrical Operation...............................................................................................................................................................50
c. vA c u u M In t e r r u p t e r A n d co n t A c t Ar e A ............................................................................................................. 50
1) Vacuum Interrupter and Contact Erosion........................................................................................................................50
2) Vacuum Integrity....................................................................................................................................................................51
3) Mechanical Adjustment of Vacuum Interrupters ...........................................................................................................51
d. op t I o n A l MA I n t e n A n c e pr o c e d u r e S ................................................................................................................... 51
1) High Potential Tests ...............................................................................................................................................................51
2) Timing.......................................................................................................................................................................................51
3) Primary Resistance Check ....................................................................................................................................................52
Ch 6 Recommended Renewal Parts and Replacement Procedures ...............................53
A. or d e r I n G In S t r u c t I o n S ..................................................................................................................................... 53
B. re c o M M e n d e d re n e W A l pA r t S ........................................................................................................................... 53
c. re p l A c e M e n t pr o c e d u r e S .................................................................................................................................. 53
1) Vacuum Interrupter Assembly.............................................................................................................................................54
2) Sliding Contact Finger Assembly........................................................................................................................................58
3) Closing Coil Assembly ...........................................................................................................................................................58
4) Primary Shunt Trip Coil Assembly ......................................................................................................................................59
5) Secondary Shunt Trip Coil Assembly .................................................................................................................................59
6) Undervoltage Device Assembly (UV).................................................................................................................................60
7) Charging Motor Assembly ...................................................................................................................................................60
8) Anti-Pump Relay Assembly..................................................................................................................................................60
9) Latch Check Switch................................................................................................................................................................61
10) Motor Cutoff Switch Assembly............................................................................................................................................61
11) Auxiliary Switch ......................................................................................................................................................................62
12) Primary Disconnecting Device Spring Assembly............................................................................................................62
Courtesy of NationalSwitchgear.com

Powered by Safety®
iv
PowlVac®STD Vacuum Circuit Breaker
IB-60201
Figures
Figure 1 PowlVac®STD Vacuum Circuit Breaker Front View with Cover......................7
Figure 2 PowlVac®STD Vacuum Circuit Breaker with Front Cover Removed ..............8
Figure 3 PowlVac®STD Vacuum Circuit Breaker Rear View ........................................9
Figure 4 Cam and Fundamental Linkage Positions ...................................................11
Figure 5 Mechanism and Trip Linkages......................................................................12
Figure 6 Operation Sequence .....................................................................................14
Figure 7 Typical AC Control Scheme ...........................................................................15
Figure 8 Typical DC Control Scheme...........................................................................15
Figure 9 Circuit Breaker with Shipping Bracket .........................................................21
Figure 10 Circuit Breaker on Crane...............................................................................22
Figure 11 Circuit Breaker in Shipping Carton...............................................................22
Figure 12 Secondary Disconnect Override Device.......................................................26
Figure 13 Secondary Disconnecting Device.................................................................31
Figure 14 Standard Circuit Breaker in Test Position ....................................................31
Figure 15 Pushing Manual Trip Operator & Accessing Racking Drive Shaft ...............32
Figure 16 Racking the Standard Circuit Breaker..........................................................32
Figure 17 Racking Drive Shaft Extension Insertion .....................................................35
Figure 18 Accessing Racking Drive Shaft Extension ....................................................35
Figure 19 Through Door Racking Option .....................................................................36
Figure 20 Anti-Rollout Latch.........................................................................................38
Figure 21 Lubrication....................................................................................................42
Figure 22 Lubrication (cont) .........................................................................................43
Figure 23 Main Closing Spring Assembly Compressed for Removal...........................44
Figure 24 Main Closing Spring Assembly Installed .....................................................45
Figure 25 Primary Trip Prop Adjustment......................................................................47
Figure 26 Feeler Gauge .................................................................................................48
Figure 27 Latch Check Switch Adjustment ...................................................................49
Figure 28 Tension Relieved on Opening Springs..........................................................54
Figure 29 Operating Pin Removal.................................................................................54
Figure 30 Lower Contact Block Setting ........................................................................56
Figure 31 Bell Crank Removal.......................................................................................56
Figure 32 Operating Yoke Setting.................................................................................56
Figure 33 Primary Current Path....................................................................................63
Figure 34 Control Devices.............................................................................................65
Courtesy of NationalSwitchgear.com

Powered by Safety®v
IB-60201
Tables
Table A Field Dielectric Test Values..................................................................................23
Table B Lubrication ..........................................................................................................41
Table C Timing..................................................................................................................51
Table D Primary Resistance..............................................................................................52
Table E Primary Current Path ..........................................................................................63
Table F Control Devices....................................................................................................64
Table G Miscellaneous Parts............................................................................................66
Courtesy of NationalSwitchgear.com

Powered by Safety®
vi
PowlVac®STD Vacuum Circuit Breaker
IB-60201
This page is intentionally left blank.
Courtesy of NationalSwitchgear.com

Ch 1 General Information
Powered by Safety®1
General Information
IB-60201
WARNINGWARNING
!
The equipment described in this document may contain high voltages and currents which can
cause serious injury or death.
The equipment is designed for use, installation, and maintenance by knowledgeable users of such
equipment having experience and training in the field of high voltage electricity. This document
and all other documentation shall be fully read, understood, and all warnings and cautions
shall be abided by. If there are any discrepancies or questions, the user shall contact Powell
immediately at 1.800.480.7273.
WARNINGWARNING
!
Before any adjustment, servicing, part replacement, or any other act is performed requiring
physical contact with the electrical working components or wiring of this equipment, the power
supply must be disconnected. Failure to follow this warning may result in injury or death.
IMPORTANTIMPORTANT
!
The information in this instruction bulletin is not intended to explain all details or variations of the
Powell equipment, nor to provide for every possible contingency or hazard to be met in connection
with installation, testing, operation, and maintenance of the equipment. For additional
information and instructions for particular problems, which are not presented sufficiently for the
user’s purposes, contact Powell at 1.800.480.7273.
Powell reserves the right to discontinue and to change specifications at any time without incurring
any obligation to incorporate new features in products previously sold.
IMPORTANTIMPORTANT
!
Courtesy of NationalSwitchgear.com

Powered by Safety®
2General Information
PowlVac®STD Vacuum Circuit Breaker
IB-60201
A. Sc o p e
The information in this instruction bulletin
describes the following PowlVac® STD vacuum
circuit breakers:
• 05PV36STD
• 05PV50STD
• 15PV25STD
• 15PV36STD
• 15PV50STD
B. pu r p o S e
The information in this instruction bulletin is
intended to provide information required to
properly operate and maintain the
PowlVac STD vacuum circuit breaker described
in Ch 1 General Information, A. Sc o p e .
This instruction bulletin provides:
1. Safety guidelines
2. General descriptions of the operation and
maintenance of the PowlVac STD vacuum
circuit breaker
3. Instructions for installation and placing the
circuit breaker into service
4. Instructions for part replacement
5. Information for ordering renewal parts
6. Procedure for critical adjustments
7. Illustrations, photographs, and description
of the circuit breaker
The illustrations contained in this document
may not represent the exact construction
details of each particular type of PowlVac STD
vacuum circuit breaker. The illustrations in this
document are provided as general information
to aid in showing component locations only.
All illustrations and photos are shown using
deenergized equipment.
Be sure to follow the appropriate safety
precaution while handling any of the
equipment. Failure to do so may result in
serious injury or death.
WARNINGWARNING
!
To the extent required, the products described
herein meet the applicable ANSI, IEEE, and
NEMA Standards; however, no such assurance
is given with respect to local codes and
ordinances which may vary greatly.
c. In S t r u c t I o n Bu l l e t I n S Av A I l A B l e el e c t r o n I c A l l y
For more information visit
www.powellind.com. To contact the
Powell Service Division call
1.800.480.7273 or 713.944.6900, or email
[e-mail].
Courtesy of NationalSwitchgear.com

Powered by Safety®3
Safety
IB-60201
Ch 2 Safety
A. SA f e Wo r k co n d I t I o n
The information in Section A is quoted from
NFPA 70E 2004 - Article 120, 120.1 Establishing an
Electrically Safe Work Condition.
120.1 Process of Achieving an Electrically Safe
Work Condition
1. Determine all possible sources of electrical
supply to the specific equipment. Check
applicable up-to-date drawings, diagrams,
and identification tags.
2. After properly interrupting the load current,
OPEN the disconnecting device(s) for each
source.
3. Wherever possible, visually verify that all
blades of the disconnecting devices are
fully OPEN or that drawout type circuit
breakers are withdrawn to the fully
disconnected position.
4. Apply lockout/tagout devices in accordance
with a documented and established policy.
5. Use an adequately rated voltage detector
to test each phase conductor or circuit part
to verify they are deenergized. Test each
phase conductor or circuit part both
phase-to-phase, and phase-to-ground.
Before and after each test, determine
that the voltage detector is operating
satisfactorily.
6. Where the possibility of induced voltages
or stored electrical energy exists, ground
the phase conductors or circuit parts
before touching them. Where it could be
reasonably anticipated that the conductors
or circuit parts being deenergized
could contact other exposed energized
conductors or circuit parts, apply ground
connecting devices rated for the available
fault duty.
B. SA f e t y Gu I d e l I n e S
Study this instruction bulletin and all other
associated documentation before uncrating
the circuit breakers.
Each user has the responsibility to instruct and
supervise all personnel associated with usage,
installation, operation, and maintenance of this
equipment on all safety procedures.
Furthermore, each user has the responsibility of
establishing a safety program for each type of
equipment encountered.
The circuit breakers described in this
instruction bulletin are operated by a
high-energy, high-speed mechanism that
is interlocked to provide specific operating
sequences. It is mandatory that the following
rules be observed to ensure the safety of
personnel associated with usage, installation,
operation, and maintenance of these circuit
breakers.
The safety rules in this instruction bulletin are
not intended to be a complete safety program.
The rules are intended to cover only some of the
important aspects of personnel safety related to
PowlVac® STD vacuum circuit breakers.
Courtesy of NationalSwitchgear.com

Powered by Safety®
4Safety
PowlVac®STD Vacuum Circuit Breaker
IB-60201
c. Ge n e r A l
1. Only supervised and qualified personnel
trained in the usage, installation, operation,
and maintenance of the circuit breaker shall
be allowed to work on this equipment. It
is mandatory that this instruction bulletin,
any supplements, and service advisories be
studied, understood, and followed.
2. Maintenance programs must be consistent
with both customer experience and
manufacturer’s recommendations,
including service advisories and instruction
bulletin(s). A well planned and executed
routine maintenance program is essential
for circuit breaker reliability and safety.
3. Service conditions and circuit breaker
applications shall also be considered in the
development of safety programs. Variables
include ambient temperature; humidity;
actual continuous current; thermal cycling;
number of operations; interrupting duty;
and any adverse local conditions including
excessive dust, ash, corrosive atmosphere,
vermin and insect infestations.
d. Sp e c I f I c
1. DO NOT WORK ON AN ENERGIZED
CIRCUIT BREAKER. If work must be
performed on a circuit breaker, remove it
from service and remove it from the
metal-clad switchgear.
2. DO NOT WORK ON A CIRCUIT BREAKER
WITH THE CONTROL CIRCUIT ENERGIZED.
3. EXTREME CARE MUST BE EXERCISED
TO KEEP ALL PERSONNEL, TOOLS, AND
OTHER OBJECTS CLEAR OF MECHANISMS
WHICH ARE TO BE OPERATED,
DISCHARGED, OR RELEASED. These
circuit breakers utilize stored energy
mechanisms. These mechanisms must be
serviced only by skilled and knowledgeable
personnel capable of releasing each spring
load in a controlled manner. Detailed
information regarding these mechanisms is
found in this instruction bulletin.
4. DO NOT ATTEMPT TO CLOSE THE CIRCUIT
BREAKER MANUALLY ON AN ENERGIZED
CIRCUIT.
5. DO NOT USE AN OPEN CIRCUIT BREAKER
AS THE SOLE MEANS OF ISOLATING A
HIGH VOLTAGE CIRCUIT. For complete
isolation, the circuit breaker shall be in
the disconnected position or shall be
withdrawn completely.
6. ALL COMPONENTS SHALL BE
DISCONNECTED BY MEANS OF A VISIBLE
BREAK AND SECURELY GROUNDED FOR
SAFETY OF PERSONNEL PERFORMING
MAINTENANCE OPERATIONS ON THE
CIRCUIT BREAKERS.
7. Interlocks are provided to ensure the
proper operating sequences of the circuit
breakers and for the safety of the user. If for
any reason an interlock does not function
as described, do not make any adjustments,
modification, or deform the parts. DO
NOT FORCE THE PARTS INTO POSITION.
CONTACT POWELL FOR INSTRUCTIONS.
Courtesy of NationalSwitchgear.com

Powered by Safety®5
Safety
IB-60201
e. X-rA y S
When high voltage is applied across the
contacts of a vacuum interrupter, there is the
possibility of generation of X-rays. The intensity
of the X-radiation is dependent on the peak
voltage and the contact gap. At the normal
operating voltage for this type of equipment,
the radiation levels are negligible. At the
voltages specified for testing, test personnel
shall be in front of the circuit breaker such that
the two layers of steel used in the frame and
front cover construction are between the test
personnel and the vacuum interrupters, and
that the test personnel be no closer than one
meter (3’) from the front of the circuit breaker.
THE CIRCUIT BREAKER SHALL BE EITHER
FULLY OPEN, OR FULLY CLOSED WHEN
MAKING HIGH POTENTIAL TESTS. DO NOT
TEST WITH CONTACTS PARTIALLY OPEN.
f. SA f e t y lA B e l S
The equipment described in this document
has DANGER, WARNING, CAUTION, and
instruction labels attached to various locations.
All equipment DANGER, WARNING, CAUTION,
and instruction labels shall be observed when
the circuit breaker is handled, operated, or
maintained.
Warning and Caution labels are located in
various places in and on the switchgear and
on the circuit breaker removable element.
Always observe these warnings and caution
labels. Do NOT remove or deface any of these
warning/caution labels.
IMPORTANTIMPORTANT
!
Courtesy of NationalSwitchgear.com

Powered by Safety®
6Equipment Description
PowlVac®STD Vacuum Circuit Breaker
IB-60201
Ch 3 Equipment Description
A. Ge n e r A l
PowlVac® circuit breakers use sealed vacuum
interrupters (Figure 3, f) to control the
primary circuit. The primary connections
to the associated metal-clad switchgear are
made by parallel copper busbars terminating
in multiple contact fingers of the primary
disconnecting devices (Figure 3, c & g). The
primary disconnecting devices, busbars, and
vacuum interrupter assemblies are supported
by insulators (Figure 3, b) specifically designed
for the application.
The primary current path side of the circuit
breaker is considered the rear of the circuit
breaker, while the side with the cover
containing the various indicators and manual
operators is considered the front of the
circuit breaker. By removing the front cover,
the operating mechanisms of the circuit
breaker are exposed. The stored energy
mechanism assembly provides motion to each
of the vacuum interrupters, moving contact
assemblies through operating pushrods
(Figure 3, y). In the same metal enclosed
compartment as the stored energy mechanism
is the circuit breaker racking mechanism and
interlocks which control the movement of the
circuit breaker between the test/disconnected
and connected positions. The racking
mechanism provides the motion to
engage/disengage the primary disconnecting
devices and to open/close the shutters in
metal-clad switchgear.
B. th e St o r e d e n e r G y Me c h A n I S M
1) Mechanical Description
The stored energy mechanism is located
in the front of the circuit breaker behind
the front cover. The front cover is held in
place by ten(10) cover bolts that may be
removed, allowing access to the stored
energy mechanism and its interlocks,
auxiliary switches, racking mechanism, and
other control devices.
CAUTIONCAUTION
!
Prior to removing the front cover, ensure the
circuit breaker is in the OPEN position and
the main closing spring is fully discharged.
Failure to do so may result in injury.
On the escutcheon of the stored energy
mechanism, there are two (2) indicators
that show the various states of operation
of the mechanism and two (2) manual
operators that will open/close the stored
energy mechanism. The circuit breaker
nameplate (Figure 1, e) is also located on
the mechanism escutcheon. If for any
reason the escutcheon is removed from the
circuit breaker, it shall be verified that the
serial number contained on the nameplate
matches the engraved serial number plate
(Figure 3, q) permanently affixed to the
rear of the circuit breaker frame prior to
installing the escutcheon.
Courtesy of NationalSwitchgear.com

Powered by Safety®7
Equipment Description
IB-60201
Figure 1 PowlVac®STD Vacuum Circuit
Breaker Front View with Cover
a. Cover Bolts
b. Front Cover
c. Breaker Position Indicator
d. Racking Drive Shaft Shutter
e. Nameplate
f. Padlock Provision - Stationary Clip
g. Padlock Provision - Movable Arm
h. Manual Trip Operator
i. Handle
j. Manual Charging Crank
k. MOC Actuator
l. Circuit Breaker Open/Closed Indicator
m. Secondary Disconnect Receptacle
n. Manual Close Operator
o. Operations Counter
p. Secondary Disconnect Latch
q. Spring Charge Indicator
a
b
p
d
ef
g
h
ji
kl
m
o
c
q
n
Courtesy of NationalSwitchgear.com

Powered by Safety®
8Equipment Description
PowlVac®STD Vacuum Circuit Breaker
IB-60201
Figure 2 PowlVac®STD Vacuum Circuit
Breaker with Front Cover Removed
a. Anti-Pump Relay
b. Opening Spring
c. Main Closing Spring
d. Connecting Rod
e. Shock Absorber (Dashpot)
f. Racking Drive Shaft Shutter
g. Primary Shunt Trip Coil
h. Secondary Trip Prop
i. MOC Actuator
j. Main Cam Roller
k. Reset Spring
l. Camshaft
m. Main Closing Cam
n. Auxiliary Switch
o Charging Motor
p. Secondary Trip Prop
Adjusting Screw
q. Latch Check Switch
r. Jackshaft
s. Holding Pawl Support Arm
t. Crank Pin
u. Holding Pawl Adjusting
Eccentric
v. Crank Arm
w. Ratchet Wheel
x. Pawl Lift Drive Plate
y. Close Latch Arm
z. Drive Pawl
aa. Close Latch Shaft
ab. Closing Coil
ac. Pawl Support Arm
ad. Motor Cutoff Cam
ae. Close Bar Adjusting Screw
af. Charging Motor Drive Shaft
ag. Motor Cutoff Switch
a
g
b
c
d
e
ih
j
k
ml
no
f
p
q
r
v
ts
u
w
xy
aa
z
ac ab
ad
ae
af
ag
Courtesy of NationalSwitchgear.com

Powered by Safety®9
Equipment Description
IB-60201
a. TOC Actuator
b. Main Insulator (Wishbone)
c. Upper Primary Disconnecting Device
d. Support Strut
e. Insulating Pole Support
f. Vacuum Interrupter
g. Lower Primary Disconnecting Device
h. Anti-Rollout Latch
i. Frame
j. Wheel
k. Crank Arm Roller
l. Racking Crank Arm
m. Racking Shaft
n. Worm Gear
o. Racking Drive Shaft
p. Ground Connection
q. Serial Number Plate
r. Sliding Contact Finger Assembly
s. Operating Pin
t. Bell Crank
u. Lock Nut
v. Spring Yoke
w. Contact Loading Spring
x. Jackshaft Pin
y. Operating Pushrod
Figure 3 PowlVac®STD Vacuum Circuit
Breaker Rear View
c
e
f
a
b
d
g
h
i
j
k
l
m
n
o
r
v
u
w
t
xy
s
p
q
Courtesy of NationalSwitchgear.com

Powered by Safety®
10 Equipment Description
PowlVac®STD Vacuum Circuit Breaker
IB-60201
The mechanism employed in the circuit
breaker is a stored energy system which
uses a charging motor to compress the
main closing spring. During the closing
operation the energy stored in the main
closing spring is released. This allows the
mechanism to close the vacuum interrupter
contacts, compress the contact loading
springs, charge the opening springs, and
overcome frictional forces. When the circuit
breaker is opened, the energy stored in
the opening and contact loading springs
is released, and the vacuum interrupter
contacts are opened.
The charging motor (figure 2, o), located
on the bottom right of the base pan, is
assembled to the circuit breaker by a
bracket that is bolted to the base pan. The
charging motor drive shaft inserts into the
eccentric drive shaft. The eccentric drive
shaft is supported by needle roller bearings
in the mechanism frame side sheets and
transmits the motor torque to the left side
of the mechanism.
When the charging motor is energized, the
eccentric drive shaft rotates and causes
the pawl support arms to pivot about the
camshaft (Figure 2, l). The drive pawl, which
is supported by the arms, engages with the
ratchet wheel and drives the ratchet wheel
one tooth at a time. To prevent backwards
motion of the ratchet, a spring-loaded
holding pawl is used to latch the ratchet
wheel after each advance from the drive
pawl.
To ensure correct synchronization of the
drive and holding pawl, the position of the
holding pawl support arms are adjustable
by the holding pawl adjusting eccentric
(Figure 2, u) located to the left front of
the mechanism. When the mechanism is
operated manually, the top pawl becomes
the drive pawl and the bottom pawl
becomes the holding pawl.
The ratchet wheel (Figure 2, w) has
projections from its side faces which
engage the drive plates as it rotates. These
drive plates are attached to the camshaft,
thus causing the camshaft to rotate.
Attached to the ends of the camshaft are
crank arms (Figure 2, v). The crank pins
(Figure 2, t) on the crank arms point
outward. The crank arms engage the
bottom ends of the connecting rods
(Figure 2, d). The pins that project from
the spring yoke, which straddles the main
closing spring, engage the top ends of the
connecting rods. As the camshaft rotates
the connecting rods will pull the spring
yoke downward, compressing the main
closing spring.
The ratchet wheel drives the camshaft so
that the connecting rods go down to their
lowest position, and then start to move
upward. At a certain point, the spring force
will overcome friction and resistance and
start to rotate the camshaft. At the same
time, the pawls are uncoupled from the
ratchet wheel by the pawl lift drive plate
(Figure 2, x) and the motor cutoff switch is
operated. The motor cutoff switch
(Figure 2, ag), located to the right of the
mechanism, is operated by the spring
charge indicator and motor cutoff cam
(Figure 2, ad). The spring charge indicator
(Figure 1, q) will display that the mechanism
is charged. The camshaft would continue
to rotate, except that it is restrained by
the close latch arm (Figure 2, y) engaging
against the close latch shaft (Figure 2, aa).
The main closing cam, located between the
mechanism side sheets, is now in a position
where the fundamental linkage can move
to the reset position.
Courtesy of NationalSwitchgear.com