GE PowerVac User manual

DEH 40368 Instructions
g
PowerVac®Vacuum Circuit Breaker
with ML-20 Mechanism

2
PowerVac®Vacuum Circuit Breaker
with ML-20 Mechanism
Table of Contents
Description Page
SECTION 1−
−−
−Introduction............................................ 4
1.1 Safety.............................................................................. 4
1.2 Maintenance ................................................................... 4
SECTION 2−
−−
−Description............................................... 5
2.1 General............................................................................ 5
2.2 Summary Description...................................................... 5
SECTION 3−
−−
−Receiving, Handling and
Storage...................................................... 5
3.1 Receiving ........................................................................ 5
A. Equipment Packages................................................. 5
B. Inspecting for Damage .............................................. 5
C. Filing a Claim............................................................. 5
3.2 Handling.......................................................................... 6
3.3 Storage............................................................................ 6
SECTION 4−
−−
−Features...................................................... 6
4.1 Safety Precautions........................................................... 6
4.2 Interlocks......................................................................... 6
4.2.1 Rating Interference Plate................................................. 6
4.2.2 Closing Spring Interlock................................................... 6
4.2.3 Negative Interlock............................................................ 7
4.2.4 Positive Interlock Bar....................................................... 7
4.2.5 Closing Spring Gag Interlock............................................ 7
SECTION 5−
−−
−Operation.................................................. 8
5.1 General............................................................................ 8
5.2 Close Spring Charging..................................................... 8
5.3 Closing Operation............................................................ 8
5.4 Opening Operation.......................................................... 9
5.5 Trip-free Operation.......................................................... 9
SECTION 6−
−−
−Control Circuit....................................... 9
SECTION 7−
−−
−Mechanical Checking and
Slow Closing......................................... 9
7.1 Visual Inspection.............................................................. 9
7.2 Closing Spring Charging .................................................. 9
7.3 Closing Spring Gag..........................................................10
7.4 Slow Closing....................................................................10
7.5 Gag Plate Removal..........................................................10
SECTION 8−
−−
−Dimensional Checks.........................11
8.1 Primary Contact Erosion ..................................................11
8.2 ML Wipe Spring Compression ........................................11
8.3 Contact Gap ....................................................................11
8.4 Close Coil Plunger Gap....................................................12
8.5 Trip Coil Plunger Gap.......................................................12
8.6 Control Switch Adjustment..............................................12
Description Page
SECTION 9−
−−
−Electrical Checks................................. 14
9.1 Electrical Operation.........................................................14
9.2 High Potential Test..........................................................14
9.2.1 Primary Circuit.................................................................14
9.2.2 Secondary Circuit ............................................................14
9.3 Primary Circuit Resistance .............................................. 14
9.4 Vacuum Interrupter Integrity Test....................................14
9.5 Insulation Test................................................................. 15
SECTION 10−
−−
−Checking and Installing
Breakers.................................................16
SECTION 11−
−−
−Maintenance....................................... 17
11.1 General ........................................................................... 17
11.1.1 PowerVac Interrupter...................................................... 17
11.1.2 Trouble Reporting........................................................... 17
11.2 Service Conditions ..........................................................17
11.3 Fault Interruptions ...........................................................17
11.4 Contact Erosion............................................................... 17
11.5 Transfer Finger Wear......................................................17
11.6 Mechanism.....................................................................17
11.7 Primary Insulation Parts...................................................17
11.8 Lubrication ......................................................................18
11.9 Recommended Maintenance..........................................18
SECTION 12−
−−
−Timing...................................................... 19
SECTION 13−
−−
−Opening and Closing Speed.. 20
SECTION 14−
−−
−Repair and Replacement...........21
14.1 General ........................................................................... 21
14.2 Replacement of Interrupter Assemblies ......................... 21
14.3 Primary Disconnect Fingers ............................................21
14.4 Mechanism.....................................................................21
14.5 Control Switches.............................................................21
14.6 Trip Coil Replacement..................................................... 21
14.7 Closing Coil Replacement............................................... 22
14.8 Auxiliary Switch Replacement......................................... 22
14.9 Motor Replacement........................................................22
14.10 “Y” Relay Replacement...................................................22
SECTION 15−
−−
−Renewal Parts....................................23
15.1 Ordering Instructions.......................................................23
SECTION 16−
−−
−Mechanical Adjustment............23
16.1 General ........................................................................... 23
16.2 Wipe Adjustment............................................................23
16.3 Contact Gap Adjustment................................................. 23
16.4 Trip Coil Plunger..............................................................24
16.5 Close Coil Plunger...........................................................24
16.6 Close Spring Discharge Interlock.....................................24
16.7 Negative Interlock........................................................... 24
INDEX ........................................................................................36
Trouble Reporting Form................................................................37

3
List of Illustrations
Figure Page
1 Front view of PowerVac®breaker with front cover.................... 6
2 Rating interference plate........................................................... 6
3 Front view of PowerVac breaker without front cover................ 8
4 Manual charging........................................................................ 9
5 Gag plate installation.................................................................10
6 Operating rod assembly............................................................10
7 Contact gap...............................................................................11
8 Close coil plunger gap...............................................................12
9 Trip coil plunger gap..................................................................12
10 Control switches .......................................................................13
11 Sample operating speed graphs................................................19
12 Contact gap adjustment ............................................................20
13 Spring discharge interlock .........................................................24
14 Toggle linkage positions of the ML-18 mechanism...................25
15 Schematic of ML-18 mechanism...............................................27
16 Typical wiring diagram for ML-18 mechanism...........................29
17 PowerVac®breaker left-front view ............................................30
18 PowerVac®breaker right-rear view............................................30
19 Trip coil and linkage...................................................................31
20 Close coil linkage.......................................................................32
21 Bottom view of the ML-18 mechanism.....................................33
22 Negative interlock .....................................................................34
23 Wipe spring compression..........................................................34
Table Page
1 Control Device and Voltage..................................................... 18
2 Measurements ....................................................................... 35
3 Adjustments............................................................................35
THESE INSTRUCTIONS ARE INTENDED FOR USE BY QUALIFIED PERSONNEL FOR INSTRUCTION AND MAINTENANCE PURPOSES.
REPRODUCTION IN WHOLE OR IN PART IS NOT PERMITTED WITHOUT THE EXPRESS PERMISSION OF GENERAL ELECTRIC.

4
PowerVac®Vacuum Circuit Breaker
with ML-20 Mechanism
SECTION 1—Introduction
This manual provides the information needed by the user to
properly install, operate and maintain the ML-20 PowerVac®
Breaker.
The PowerVac®vacuum breaker is a horizontal drawout
interrupting element for use in metalclad switchgear to provide
protection and control of electrical apparatus and power systems.
To the extent required applicable ANSI, IEEE and NEMA Standards
are met. No such assurances are given with respect to local
codes and ordinances, as they vary greatly.
1.1—Safety
Each user must maintain a safety program for the protection of
personnel, as well as other equipment, from the potential hazards
associated with electrical equipment.
The following requirements are intended to augment the user's
safety program, but NOT supplant the user's responsibility for
devising a complete safety program. The following basic industry
practiced safety requirements are applicable to all major electrical
equipment such as switchgear or switchboards. GE neither
condones nor assumes any responsibility for practices which
deviate from the following:
1. ALL CONDUCTORS MUST BE ASSUMED TO BE ENERGIZED
UNLESS THEIR POTENTIAL HAS BEEN MEASURED AS
GROUND AND ADEQUATE CAPACITY GROUNDING
ASSEMBLIES HAVE BEEN APPLIED TO PREVENT
ENERGIZING. Many accidents have been caused by
unplanned energization from non-recognized back feeds,
equipment malfunctions, and from a wide variety of sources.
2. It is strongly recommended that all equipment be completely
de-energized, verified to be “dead”, then grounded with
adequate capacity grounding assemblies prior to any
maintenance. The grounding cable assemblies must be able
to withstand energizing fault levels so that protective
equipment may clear the circuit safely. Additional discussion
on this concept is covered in Chapter 20 of ANSI/NFPA 70B,
Electrical Equipment Maintenance.
3. Although interlocks to reduce some of the risks are provided,
the individual's actions while performing service or
maintenance are essential to prevent accidents. Each person's
knowledge; mental awareness; and planned and executed
actions often determine if an accident will occur. The most
important method of avoiding accidents is for all associated
personnel to carefully apply a thorough under-standing of the
specific equipment from the viewpoints of its purpose, its
construction, its operation and the situations which could be
hazardous.
All personnel associated with installation, operation and
maintenance of electrical equipment, such as power circuit
breakers and other power handling equipment, must be
thoroughly instructed, with periodic retraining, regarding power
equipment in general as well as the particular model of
equipment with which they are working.
Instruction books, actual devices and appropriate safety and
maintenance practices such as OSHA publications, National
Electric Safety Code (ANSI C2), National Electric Code, and
National Fire Protection Association (NFPA) 70B Electrical
Equipment Maintenance must be closely studied and followed.
During actual work, supervision should audit practices to assure
conformance.
1.2—Maintenance
Excellent maintenance is essential for reliability and safety of any
electrical equipment. Maintenance programs must be tuned to
the specific application, well planned and carried out consistent
with both industry experience and manufacturer's
recommendations. Local environment must always be considered
in such programs, including such variables as ambient
temperatures, extreme moisture, number of operations, corrosive
atmosphere or major insect problems and any other unusual or
abusive condition of the application. One of the critical service
activities, sometimes neglected, involves the calibration of various
control devices. These monitored conditions in the primary and
secondary circuits, sometimes initiating emergency corrective
action such as opening or closing circuit breakers. In view of the
vital role of these devices, it is important that a periodic test
program be followed. As was outlined above, it is recognized that
the interval between periodic checks will vary depending upon
environment, the type of device and the user's experience.
It is the GE recommendation that, until the user has accumulated
enough experience to select a test interval better suited to the
individual requirements, all significant calibrations be checked at
an interval of one to two years.
To accomplish this, some devices can be adequately tested using
test sets. Specific calibration instructions on particular devices
typically are provided by supplied instruction books.
Instruction books supplied by manufacturers address components
that would normally require service or maintenance during the
useful life of the equipment. However, they can not include every
possible part that could under adverse environments.
Maintenance personnel must be alert to deterioration of any part
of the supplied switchgear, taking actions, as necessary to restore
it to serviceable status.
Industry publications of recommended maintenance practices
such as ANSI/NFPA 70B, Electrical Equipment Maintenance,
should be carefully studied and applied in each user's formation of
planned maintenance.
Some users may require additional assistance from GE in the
planning and performance of maintenance. Local GE Sales can be
contracted to either undertake maintenance or to provide
technical assistance such as the latest publications.
The performance and safety of all equipment may be
compromised by the modification of supplied parts or their
replacement by non-identical substitutes. All such design changes
must be qualified to the original manufacturers specifications.
The user should methodically keep written maintenance records
as an aid in future service planning and equipment reliability
improvement. Unusual experiences should be promptly
communicated to GE.

5
SECTION 2—Description
2.1—General
This section contains a description of the PowerVac®vacuum
circuit breaker. It also describes the functions of the electrical
and mechanical systems.
2.2—Summary Description
The PowerVac® vacuum circuit breaker uses sealed vacuum
power interrupters to establish and interrupt a primary circuit.
Primary connections to the associated metalclad switchgear are
made by horizontal bars and disconnect fingers, electrically and
mechanically connected to the vacuum interrupters. Molded
interrupter supports, one per phase on a three-phase circuit
breaker, provide mountings for the primary bars, interrupters,
current transfer fingers, and heat dissipation fins (where used).
The operating mechanism provides direct motion at each phase
location in order to move the movable contact of the vacuum
interrupters from an open position to a spring-loaded closed
position and then back to the open position on command.
The ML-20 mechanism is of the stored-energy type and use a
gear motor to charge a closing spring. During a closing operation,
the energy stored in the closing spring is used to close the
vacuum interrupter contacts, compress the wipe springs which
load the contacts, charge the opening springs, and overcome
bearing and other friction forces, The energy then stored in the
wipe springs and opening springs will open the contacts during an
opening operation.
Closing and opening operations are controlled electrically by the
metalclad switchgear or remote relaying. Mechanical control is
provided by manual close and trip buttons on the circuit breaker.
The closing spring may be manually charged, and a method for
slow-closing the primary contacts is available. The mechanism will
operate at the ac or dc voltage indicated on the circuit breaker
nameplate.
Mechanical and electrical interlocks are provided and are
described in para 4.2, Interlocks
SECTION 3—Receiving, Handling and Storage
3.1—Receiving
A. Equipment Packages
Every package leaving the factory is plainly marked with the case
number, requisition number, and customer’s order number. If the
equipment has been split for shipment, the section numbers of
the equipment enclosed in each shipping package are identified.
NOTE: To avoid loss of any parts when unpacking, the contents
of each container should be carefully checked against the packing
list before discarding the packing material.
Contents of each shipping package are listed on the Master
Packing List. In addition, this list includes the number of the
shipping crate in which miscellaneous parts needed to install and
operate equipment (such as hardware, contact lubricant, touch-up
paint, breaker closing devices, etc.) are located. Normally, such
devices are packed in a cardboard carton.
B. Inspecting for Damage
All equipment leaving the factory is carefully inspected and
packed by personnel experienced in the proper handling and
packing of electrical equipment. Upon receipt of any equipment,
immediately perform a visual inspection to ascertain if any
damage has been sustained in shipping or if there are any loose
parts.
C. Filing a Claim
If any damage is evident, or indication of rough handling is
visible, file a claim for damage at once with the transportation
company and notify the nearest GE Company Sales Office
immediately. Information on damaged parts, part number, case
number, requisition number, etc., should accompany the claim.
3.2—Handling
When lifting the breaker, use of the specially designed lift truck is
recommended. If it is necessary to lift the breaker with a hoist use
four 1/2 inch diameter hooks rated at least 500 pounds each.
Lifting holes are provided in the four corners of the frame
members. (See figure 2) Use a spreader wider than the breaker
to prevent slings from contacting the interrupter supports.
3.3—Storage
It is recommended that the breaker be put immediately in its
permanent location. If this is not possible, the following
precautions must be taken to assure proper breaker storage.
1. The breaker should be protected against condensation,
preferably by storing it in a warm dry room of moderate
temperature such as 40° - 100°F. Circuit breakers for outdoor
metalclad switchgear should be stored in the equipment only
when power is available and the heaters are in operation to
prevent condensation.
2. The breaker should be stored in a clean location, free from
corrosive gases or fumes; particular care, for example,
should be taken to protect the equipment from moisture and
cement dust, as this combination is present at construction
sites and has a very corrosive effect on many parts.
3. Rollers, latches, etc., of the operating mechanism should
be coated with 0282A2048P009 grease to prevent
rusting.
If the breaker is stored for any length of time, it should be
inspected periodically to see that rusting has not started and
to ensure good mechanical condition. Should the breaker be
stored under unfavorable atmospheric conditions, it should be
cleaned and dried out before being placed in service.

6
SECTION 4—Features
4.1—Safety Precautions
This circuit breaker uses powerful springs for energy storage.
WARNING: DO NOT WORK ON THE INTERRUPTERS OR
THE MECHANISM UNLESS THE CIRCUIT BREAKER IS IN THE
“OPEN” POSITION AND BOTH THE CLOSING AND OPENING
SPRINGS ARE EITHER DISCHARGED OR GAGGED AND ALL
ELECTRICAL POWER IS REMOVED.
These precautions are required to prevent accidental
operation. Anyone working on the circuit breaker should be
familiar with the contents of this instruction book.
Figure 1 Front view of PowerVac breaker
with front cover
1. Front cover 6. Manual charge lever
2. Cover mounting bolts 7. Counter
3. Manual trip button 8. Spring charge indication
4. Manual close button 9. Closing spring gag access
5. Nameplate 10. Open/Close indicator
The circuit breaker has been shipped in the CLOSED position.
After removing packing material, open the breaker by pushing
in firmly on the manual trip button (3, Figure 1), while keeping
hands away from moving parts, and verify that the operation
counter advances one count.
Closing and opening springs are now in their discharged
positions. Check this by first pressing the manual close button,
then the manual trip button. The indicator flags on the front of
the breaker should show “OPEN” and “DISCHGD”. All
mechanical and electrical checks should be completed before
putting breakers in service.
4.2—Interlocks
Each PowerVac®vacuum circuit breaker is provided with the
following interlocks:
4.2.1 Rating Interference Plate
This interlock (1, Figure 2) permits only a breaker with a
matching continuous current, voltage and interrupting rating to
be inserted into a metalclad compartment of identical rating.
Figure 2 Rating interference plate
1. Rating interference plate
2. Lifting locations (3/4” dia. hole at all four corners)
4.2.2 Closing Spring Interlock
This racking-track operated interlock (4, Figure 18) prevents
racking into or out of the metalclad compartment a breaker
that has the closing spring charged. This action is
accomplished by a roller on the right side of the breaker
mechanism which contacts the racking mechanism and
discharges the closing spring, unless the breaker is in the
“DISCONNECT/TEST” position or the “CONNECT” position in
the metalclad compartment. This interlock also opens the
CL/MS switch in the motor circuit to prevent electrical
charging of the closing spring when the breaker is between
the “DISCONNECT/TEST” and “CONNECT” position in the
metalclad compartment.
2
1
1
10
6
7
2
4
8
3
2
5
9

7
4.2.3 Negative Interlock
The function of this racking-track operated interlock (5, Figure
17) is to remove the trip latch from the trip roller thereby
preventing a closing operation. The interlock also opens the
LCS switch in the closing circuit thereby removing the close
circuit power. The negative trip interlock is functional while
the breaker is being moved between the
“DISCONNECT/TEST” and “CONNECT” position and upon
withdrawal from the metalclad compartment.
4.2.4 Positive Interlock Bar
This interlock will prevent the racking of a closed breaker into
or out of a metalclad compartment. A linkage connected to
the cross shaft extends a détente angle (3, Figure 17) out
through the left side of the mechanism frame when the
breaker contacts are in the closed position. If the breaker is in
the “CONNECT” or “DISCONNECT/TEST” position in the
metalclad the détente angle locks into the racking mechanism
to prevent access to the hex section of the racking screw.
4.2.5 Closing Spring Gag Interlock
The interlock is provided to prevent a breaker that has a
gagged closing spring from entering a metalclad unit. This
function is accomplished by projecting an angle (1, Figure 17)
out of the left front side of the mechanism when the closing
spring is gagged. This angle will interfere with the racking
mechanism and block entry into the metalclad unit when the
Closing Spring Gag Access Door is open.

8
SECTION 5—Operation
5.1—General
The PowerVac®vacuum circuit breaker uses sealed vacuum
power interrupters to establish and interrupt a primary circuit.
Primary connections to the associated metalclad switchgear
are made by horizontal bars and disconnect fingers, electrically
and mechanically connected to the vacuum interrupters.
Molded interrupter supports, one per phase on a three-phase
circuit breaker, provide mountings for the primary bars,
interrupters, current transfer fingers, and heat dissipation fins
(where used). The operating mechanism provides direct
motion at each phase location in order to move the lower
contact of the vacuum interrupters from an open position to a
spring-loaded closed position and then back to the open
position on command.
The ML-20 mechanism (Figure 15) is of the stored-energy
type and uses a gearmotor to charge a closing spring. During
a closing operation, the energy stored in the closing spring is
used to close the vacuum interrupter contacts, compress the
wipe springs which load the contacts, charge the opening
spring, and overcome bearing and other friction forces, The
energy then stored in the wipe springs and opening spring will
open the contacts during an opening operation.
Closing and opening operations are controlled electrically by
the metalclad switchgear or remote relaying. Mechanical
control is provided by manual close and trip buttons on the
circuit breaker. The closing spring may be manually charged,
and a method for slow-closing the primary contacts is
available. The mechanism will operate at the ac or dc voltage
indicated on the circuit breaker nameplate.
5.2—Close Spring Charging
Figure 15 shows a front view of the ML-20 in a schematic
form. The primary contacts are open and the closing spring is
charged. The closing spring charging system consists of a
closing spring (1, view B) mounted on the left side of the
breaker and the electrical charging system mounted on the
right side of the breaker. Both components are fastened to
the cam shaft (2, view B). A manual charging system (3, view
A) is provided so that the mechanism can be slow closed and
the closing spring can be charged without electrical control
power.
Spring charging is accomplished electrically by a rotating
eccentric on the output shaft of the gear motor driving pivoted
charging arms (4, view C) which oscillate about the centerline
of a ratchet wheel (5, view C). A driving pawl (6, view C),
mounted within the charging arms, oscillates with the
charging arms. Starting from its rear-most position, as the
charging arms rotate forward, a spring forces engagement of
the driving pawl with a tooth of the ratchet wheel. The ratchet
wheel is advanced by the rotating charging arms and pawl
assembly. Advancement of one tooth spacing is provided for
each oscillation of the system. The ratchet motion is restricted
to one direction by a spring-loaded holding pawl that prevents
the ratchet wheel from going backwards as the charging arms
oscillate back to pick up the next tooth. Thirteen complete
cycles of the charging arms are needed for a full charge of the
closing spring. The efficient, compact gear motor
accomplishes this action in about three seconds. When the
charging cycle is complete, the ratchet wheel is positioned so
that three missing teeth adjacent to the driving pawl and any
motor overspin will not drive the ratchet wheel, thus
preventing damage to the system.
When the spring is completely charged, the assembly is
retained in that position by the close latch, until it is desired
to close the circuit breaker.
The closing coil cannot be electrically energized unless the
closing spring is completely charged. This action is prevented
by the 52/CHG switch in the closing circuit.
The manual charging system (3, view A) works directly on the
cam shaft where a one-way clutch (7, view A), driven by a
manual handle, provides rotation of the ratchet wheel. Manual
pumping of the handle advances the ratchet wheel and the
holding pawl prevents counter-rotation while the handle is
returning for another stroke. Approximately eight complete
strokes of the manual handle are required for one complete
spring-charging operation. When the spring charge indicator
(9, Figure 3) shows “CHARGED”, MANUAL CHARGING MUST
BE DISCONTINUED TO AVOID MECHANISM DAMAGE.
Figure 3 Front view of PowerVac®breaker
without front cover
1. Upper interrupt connection 8. Counter
2. Interrupter support 9. Spring charge indication
3. Operating rod 10. Manual charge lever
4. Racking arm 11. Manual close button
5. Compartment track rollers 12. Test position handle for
6. Manual trip button secondary disconnects
7. Open/Close indicator 13. Closing spring gag access
5.3—Closing Operation
(refer to Figure 15)
By either energizing the close solenoid or depressing the
manual close button, the close latch (8, view C) is rotated,
releasing the closing spring (1, view B). This action releases
the energy in the closing spring and transmits it to the closing
cam (9, view D) and closing roller (10, view D) and causes
1
12
2
3
4
5
10
11
8
13
9
6
9 7
5
4

9
the linkage to rise until the prop (11, view D) can slip under
the close roller (10, view D) and hold the linkage in place. As
the linkage moves, the output crank (12, view D) rotates the
cross shaft (13, view D) which in turn rotates the phase bell
cranks and compresses the two opening springs (15, view E)
on poles 1 and 3, this closes the vacuum interrupters, and
compresses the three wipe springs (16, view E) on each pole.
The rotation of the cross shaft (13, view D) also changes the
auxiliary switch (7, view D) position. The position flag on the
front panel will then indicate “CLOSED”. After the breaker is
closed, the charging motor is again energized and the closing
spring is charged as described under “CLOSE SPRING
CHARGING”. Spring charging is possible when the breaker is
in the closed position because the linkage is held in place by
the prop.
5.4—Opening Operation (refer to Figure 15)
By either energizing the trip solenoid or depressing the
manual trip button (23, view B), the trip latch (19, view D) is
rotated, permitting the linkage to collapse and the vacuum
interrupter contacts to open under the force of the wipe
springs (16, view E) and opening springs (15, view E). At the
end of the opening stroke, the center phase wipe spring
assembly hits a stop block on the frame that limits overtravel
and rebound. Rotation of the cross shaft from the closed to
the open position operates the auxiliary switch (17, view D)
which opens the trip coil circuit. If the closing spring has been
recharged, the linkage will be reset and the trip latch will be in
place on the trip roller, ready for another closing operation.
5.5—Trip-free Operation
The linkage is mechanically trip free in any location on the
closing stroke. Electrically energizing the trip coil while closing
will, after the auxiliary switch contacts change position, rotate
the trip latch and permit the circuit breaker to open fully.
The linkage will reset as in a normal open operation, and the
closing spring will recharge as described under SPRING
CHARGING.
SECTION 6—Electric Control circuit
A typical PowerVac®circuit breaker ML-20 mechanism wiring
diagram is shown in Figure 16. Check the wiring diagram
supplied with the actual circuit breaker for its wiring.
The close spring-charging motor circuit is established through
the CL/MS (close latch monitor switch) switch if the close
latch is reset the SM/LS (spring motor limit switch) if the
closing spring is discharged and the IL/MS (Negative Interlock
Monitoring Switch). When the closing spring is charged, the
SM/LS interrupts the circuit.
The close coil circuit is established through two normally
closed 52Y relay contacts, and the latch-checking switch LCS,
if the trip latch is reset. An auxiliary switch contact 52b is also
in series with the close coil and closes when the breaker is
open and opens when the breaker is closed. During a close
operation, cam rotation closes the SM/LS contact allowing the
52Y relay to be energized; opening its contacts in the close
coil circuit and sealing itself in through one of its own contacts
to the close signal. This seal-in action prevents re-closing on a
sustained close command as the close signal must be
removed to drop out the Y relay, and reestablish the close
circuit, thereby providing an anti-pump feature.
Circuit breaker mounted auxiliary switch contacts not used in
the control circuit are bought out for control and indication
functions. The metalclad equipment may provide a breaker
operated stationary auxiliary switch for additional contacts
(3, 6 or 10 stages are available).
SECTION 7—Mechanical Checking and Slow Closing
7.1—Visual Inspection
Visually inspect the circuit breaker for any signs of damage or
loose hardware.
7.2—Closing Spring Charging
Manually charge the breaker closing spring using the charging
handle provided (1, Figure 4). The closing spring is charged by
a ratcheting mechanism that advances by one ratchet tooth at
a time. When the spring is fully charged and the spring load is
held by the closing latch, the spring indicator (3, Figure 1) will
change from “DISCHGD” to “CHARGED”, and a positive snap
will be heard as the spring travels over center.
CAUTION: AFTER THE SPRING IS COMPLETELY
CHARGED, AS INDICATED IN FIGURE 4, FURTHER FORCING
CHARGING HANDLE MAY CAUSE DAMAGE TO THE
CLOSING LATCH AND ITS ASSOCIATED PARTS.
Figure 4 Manual charging
1. Manual charging handle
2. Close spring gag hole
(shown in closed position)
3. Spring charge indication
3
1
2

10
Figure 5 Gag plate installation
1 Closing spring gag plate
2 Manual charging lever
7.3—Closing Spring Gag
Insert the closing spring gag plate (1, Figure 5) by opening the
closing spring gag hole cover and inserting the tip of the gag
plate between the end of the spring and the spring guide and
engaging the détentes on the gag plate into the slots in the
closing spring guide. Note that when the closing spring guide
is exposed for gagging, an interference angle is exposed on
the left side of the breaker (1, Figure 17). With the closing
spring in the gagged position, this angle will provide
interference preventing use of the lift truck and racking of the
breaker element. No attempt should be
made to alter, modify or otherwise make inoperative this
safety feature. With the gag plate in position, depress the
manual close button. This action will partially discharge the
closing spring and also partially close the vacuum interrupter
contacts. Do not energize the secondary control circuit at this
time.
7.4—Slow Closing
To manually slow close the breaker contacts, install the
closing spring gag, as described above, and push the manual
close button (11, Figure 3). Then put the manual charge
handle on the manual charge lever and move the handle up
and down. The breaker will be fully closed when the spring
charge indicator shows “CHARGED”.
CAUTION: WITH THE GAG PLATE INSTALLED, THE
BREAKER CLOSED, AND OPENING SPRINGS CHARGED, THE
BREAKER CAN BE TRIPPED AT FULL SPEED.
7.5—Gag Plate Removal
To remove the gag plate, the closing spring must be fully
charged. If the spring charge indicator does not show
“CHARGED” in the window, manually charge the spring until
it does. Lift up and push in on the gag plate to clear the
détentes on the gag plate from the slots in the closing spring
guide. While holding the gag plate up, remove it from the
opening. Close the gag hole cover. For safety, first close the
breaker by depressing the manual “CLOSE” button and then
depress the manual “TRIP” button. All stored energy is now
removed from the breaker.
Figure 6 Operating rod assembly
1. Erosion Marker 4. Hexagon projection 7. Clamp screws
2. Lock nut 5. Operating rod insulator 8. Interrupter movable contact rod
3. Lock washer 6. Coupling clamp
2
1
8
7
6
5
4
3
2
1

11
SECTION 8—Dimensional Checks
With the breaker closed and the gag plate installed, perform
the following dimensional checks.
8.1—Primary Contact Erosion
In the closed position, the erosion marker (1, Figure 6) below
the bus bar is aligned with a reference mark on the
interrupter’s movable stem. As contact erosion occurs, the
erosion mark will move upward away from the erosion
pointer. When the seribed band on the interrupter’s movable
stem is completely above the top surface of the pointer, 1/8
inch erosion has occurred and the interrupter should be
replaced.
8.2—ML-20 Wipe Spring Compression
With the breaker closed and the closing spring gagged,
measure with a feeler gauge and record the distance between
the bellville washer and the trunion between the bell crank
arms.
8.3—Contact Gap
The method of measuring the contact gap is as follows: With
the breaker in the open position, the closing springs charged,
and the closing spring gag plate installed, apply a piece of
masking tape to the surface of the operating rod insulator as
shown in Figure 7. Using a reference block, make a mark on
the tape near the top on all three poles. It is also advisable to
put a reference mark on the tape to identify to which pole the
tape is applied. Remove the closing spring gag plate and close
the breaker. Using the same procedure as above, re-mark the
tape. This new mark will be near the bottom of the tape. Trip
the breaker, remove the tapes and re-apply them to a flat
surface. Measure the distance between the two lines.
A caliper will give an accurate reading of the contact gap,
Dimension G: The gaps must be between the 0.655 inch
maximum at the center pole and 0.595 inch minimum at the
outer poles. It is not necessary that all readings correspond. A
typically adjusted breaker will have more gap and wipe on the
center pole than on the outside poles.
The close coil and trip coil plunger gap dimensional checks are
made in the operating mechanism which is accessible from
the bottom. To accommodate these checks, the breaker
should be turned on its right side resting on two-by-four wood
blocks. DO NOT use the portable breaker lift truck.
CAUTION: DO NOT ALLOW ANYTHING TO COME IN
CONTACT WITH THE INTERLOCK ROLLER (4, Fig. 18) ON
THE RIGHT SIDE OF THE MECHANISM.
Figure 7 Contact gap

12
8.4—Close Coil Plunger Gap
The close coil plunger gap is shown in Figure 8. With the
closing spring discharged, operate the plunger to make certain
that the plunger moves freely over its full stroke in the coil. To
check the closing coil plunger gap the breaker should be open
and the closing spring charged and gagged. Depress the close
plunger button until resistance is felt. The gap between the
plunger button and the coil housing should be as follows:
Figure 8 Close coil plunger gap
8.5—Trip Coil Plunger Gap
The trip coil plunger gap is shown in Figure 9. With the
breaker in the open position and the closing spring in the
charged position, make certain that the trip linkage and trip
shaft move freely over the full plunger travel. To check the trip
coil plunger gap adjustment, the breaker is to be closed with
the closing spring discharged. Dimension T between the
plunger button and the coil housing should be between 0.20
and 0.25 inch. This dimension is obtained when the trip
plunger button is depressed until resistance is felt. If the
breaker is equipped with an optional second trip coil, use
same procedure.
Figure 9 Trip coil plunger gap
8.6—Control Switch Adjustment
The breaker is to be in the open position with the opening and
closing springs discharged. This results in the control switch
plungers being in the depressed position. The switches to be
checked are shown in Figure 10. On the LCS and stacked
switches (SM/LS & CHG), the plunger rod is to be recessed
within the rear of the switch body and this recess is to be 0 to
1/32 inch. This is a visual check. No adjustment is required on
the CL/MS or the IL/MS.

13
Figure 10 Control switches
LCS Switch

14
SECTION 9—Electrical Checks
Electrical checking consists of electrical breaker operation
primary and secondary wiring high-potential testing (if
required), primary circuit resistance (if required). Interrupter
high-potential testing, and insulation resistance to ground.
9.1—Electrical Operation
To check the electrical operation, attach a secondary test
coupler to the circuit breaker connector. Check the control
voltage on the nameplate and close and open the breaker
several times.
CAUTION: REPEATED OPERATIONS AT A RATE EXCEED-
ING TWO PER MINUTE MAY CAUSE CHARGING MOTOR
OVERHEATING AND FAILURE.
9.2—High-Potential Test
If high potential tests to check the integrity of the primary
insulation is required, the AC high potential test described
below is strongly recommended. DC high potential testing is
not recommended. The following procedure must be adhered
to.
CAUTION: IF DC HIGH POTENTIAL TESTING IS REQUIRED,
THE DC HIGH POTENTIAL MACHINE MUST NOT PRODUCE
PEAK VOLTAGES EXCEEDING 50 KV.
NOTE: Always recheck with an AC tester if initial results are
questionable.
9.2.1 Primary Circuit
The breaker should be hipotted in the closed breaker mode.
An AC hipot machine capable of producing the test voltages
shown below may be used to hipot the breaker phase to
phase and phase to ground.
BREAKER VOLTAGE AC TEST VOLTAGE
27.0 kV 45 kV
The machine should be connected with its output potential at
zero and the voltage increased at 500 volts per second to the
test voltage and that voltage maintained for 60 seconds. The
voltage should then be returned to zero and the test leads
removed and the breaker discharged to ground. Do not
exceed the test voltage indicated.
If the test should experience a failure, STOP
STOPSTOP
STOP, turn off the test
set and discharge the test sample. 1. Check the test setup
and leads for connection errors. 2. Wipe down the breaker to
remove any moisture, dust and contamination. 3. Retest the
breaker at the proper test voltage.
9.2.2 Secondary Circuit
Prior to hipotting the breaker secondary circuit, disconnect
the motor leads and thread a wire connecting all secondary
disconnect pins except #24, the ground pin. Connect the hipot
machine from this wire to ground. Increase the voltage to
1125 volts (rms) 60 Hz and maintain for 60 seconds. Reduce
the voltage to zero and remove the hipot machine from the
circuit. Remove the wire connecting the secondary disconnect
pins and reconnect the motor leads.
9.3—Primary Circuit Resistance
A resistance check of the primary circuit may be made
with the breaker closed. Use a low resistance measuring
instrument rated 100 amperes which measures in microhms.
The 100 ampere reading should be 25 or less microhms for a
600/1200 or 2000 amp. Breaker, when connected across the
upper and lower primary bars on the breaker side of the
disconnect fingers. Do not connect directly to the disconnect
fingers as errors may occur due to finger spring pressure
9.4—Vacuum Interrupter Integrity Test
NOTE: Use of a DC hipot is not recommended, but can be
used for quick field checks only. Always recheck with an AC
tester if initial results are questionable. Prior to performing any
vacuum interrupter integrity test, the outside (external
surface) of the vacuum interrupters should be wiped clean of
any contaminates with a non-linting cloth or industrial type
wiper. This is critical: the entire external surface is to be
completely free of all dirt, debris, dust, oil, etc.
CAUTION: X-RADIATION WILL BE PRODUCED IF AN
ABNORMALLY HIGH VOLTAGE IS APPLIED ACROSS A PAIR
OF ELECTRODES IN A VACUUM. X-RADIATION WILL
INCREASE AS VOLTAGE INCREASES AND/OR AS CONTACT
SEPARATION DECREASES. ONLY TEST A CORRECTLY-
ADJUSTED CIRCUIT BREAKER.
DURING A HIGH POTENTIAL OR A VACUUM INTEGRITY
TEST, ANY X-RADIATION WHICH MAY BE PRODUCED WILL
NOT BE HAZARDOUS AT A DISTANCE SAFE FOR HIGH
POTENTIAL TESTING, IF THE TEST IS CONDUCTED AT THE
RECOMMENDED VOLTAGE AND WITH THE NORMAL OPEN
CIRCUIT BREAKER GAP.
DO NOT APPLY VOLTAGE THAT IS HIGHER THAN THE
RECOMMENDED VALUE. DO NOT USE CONTACT SEPA-
RATION THAT IS LESS THAN THE RECOMMENDED OPEN-
POSITION BREAKER CONTACT GAP.
The vacuum integrity test is performed using an AC hi-
potential tester. A vacuum integrity test of the interrupter is
required to insure that no loss of vacuum has occurred. This
test of the vacuum interrupter will determine its internal
dielectric condition and vacuum integrity. With the breaker
open, individually check each interrupter by connecting the hi-
pot machine “Hot” lead to the upper primary bus bar and the
ground lead to the lower bus bar. If the machine has a center
point ground, the connections can be made either way. Apply
36 kV (rms) 60 Hz at 500 vps and hold for 10 seconds. If no
breakdown occurs, the interrupter is in acceptable condition.
After the high potential voltage is removed, discharge any
electrical charge that may be present through the internal

15
ground of the test machine or by applying a grounded cable to
the phase bus bars.
If a failure of a vacuum bottle should incur during the integrity
test, the test procedure should be reviewed and the pole
piece cleaned. Failure rates for vacuum bottles is 0.0007 per
field unit.
Note the voltage level at failure on the first test; then perform
a retest on the phase pole piece. If the pole piece passes the
retest, the vacuum bottle is acceptable - STOP
STOPSTOP
STOP. If the test fails
again but at a higher voltage level than was observed in the
first test. Clean the pole piece and retest. If a failure of the
integrity test occurs a third time, consider the vacuum bottle
to have lost vacuum and replace the complete pole piece as
described under Repair of Interrupter Assembly.
CAUTION: MANY DC HIGH POTENTIAL MACHINES ARE
HALFWAVE RECTIFIERS. THIS TYPE OF HIPOT TESTER
MUST NOT
NOTNOT
NOT BE USED TO TEST VACUUM INTERRUPTERS.
THE CAPACITANCE OF THE POWERVAC BOTTLES IS VERY
LOW AND THE LEAKAGE IN THE RECTIFIER AND ITS DC
VOLTAGE MEASURING EQUIPMENT IS SUCH THAT THE
PULSE FROM THE HALFWAVE RECTIFIER MAY BE IN THE
NEIGHBORHOOD OF 120 kV WHEN THE METER IS
ACTUALLY READING 40 kV. IN THIS CASE, SOME PER-
FECTLY GOOD BOTTLES CAN SHOW A RELATIVELY HIGH
LEAKAGE CURRENT SINCE IT IS THE PEAK VOLTAGE OF 120
kv THAT IS PRODUCING ERRONEOUS BOTTLE LEAKAGE
CURRENT. IN ADDITION, ABNORMAL X-RADIATION WILL
BE PRODUCED.
Although a AC hi-potential test is recommended for checking
the vacuum integrity, a DC hi-potential test can also be
conducted on the vacuum interrupters at 50 kV and held for 10
seconds with the restrictions noted as follows:
No attempt should be made to try to compare the condition
of one vacuum interrupter with another nor to correlate the
condition of any interrupter to low values of dc leakage
current. There is no significant correlation. After the high
potential voltage is removed, discharge any electrical charge
that may be retained.
Acceptable AC high potential machines are:
Hipotronics Model 7BT 60A
Hipotronics Model 60HVT
James G. Biddle Catalog 222060
Phoenix Model 660-10P
Acceptable DC high potential machines are:
Hipotronics Model 860PL
Hipotronics Model 880PL
9.5—Insulation Tests
The primary circuit insulation on the breaker may be checked
phase to phase and phase to ground using a 2500 Volt or
other suitable megohmeter.
Since definite limits cannot be given for satisfactory insulation
values, a record should be kept of the megohmeter readings
as well as temperature and humidity readings. This record
should be used to detect any weakening of the insulation from
one check period to the next. Generally, readings should equal
or exceed 10,000 megohms.
To measure the breaker secondary circuit insulation
resistance, disconnect the motor leads and thread a wire
connecting together all secondary disconnect pins except
#24, the ground pin. The measurement is made by
connecting a 500 Volt megohmeter from the wire to ground.

16
SECTION 10—Checking and Installing Breakers
CAUTION: IF THE COMPARTMENT SECONDARY CON-
TROL CIRCUITS ARE ENERGIZED, THE FOLLOWING
PROCEDURE SHOULD BE FOLLOWED TO PREVENT
ARCING AND BURNING OF THE MOTOR CIRCUIT PINS IN
THE SECONDARY CONTACT BLOCKS: EITHER CHARGE THE
CLOSING SPRING MANUALLY, OR PUSH IN AND HOLD THE
MANUAL CLOSE BUTTON TO OPEN THE MOTOR CIRCUIT,
THEN PULL DOWN THE HANDLE AND EXTEND THE
BREAKER SECONDARY CONTROL CONTACT BLOCK TO
FIRMLY ENGAGE WITH ITS MATING SECONDARY CONTROL
CONTACT BLOCK IN THE COMPARTMENT. RELEASE
CLOSE BUTTON TO ACTIVATE SPRING CHARGING MOTOR.
Verify that spacing between the lower inside edges of the
breaker roller track in the metalclad compartment is 29.807”
min. to 29.857” max. Check that the breaker is OPEN and that
the closing spring is DISCHARGED. Install the PowerVac®
circuit breaker into the DISCONNECT/TEST position in the
metalclad compartment.
CAUTION: IF CONTROL POWER IS AVAILABLE, CLOSE
THE CIRCUIT BREAKER USING THE CONTROL SWITCH ON
THE COMPARTMENT DOOR. THIS OPERATION WILL
CHECK THE ADJUSTMENT OF THE 52/LCS SWITCH. IF THE
BREAKER WILL NOT CLOSE ELECTRICALLY, RECHECK THE
52/LCS ADJUSTMENT. IF CONTROL POWER IS NOT AVAIL-
ABLE, PUSH THE MANUAL CLOSE BUTTON AND
RECHARGE THE CLOSING SPRING MANUALLY. SPRING
CHARGING WILL OCCUR AUTOMATICALLY IF CONTROL
POWER IS CONNECTED.
With the breaker in the CLOSED condition, attempt to install
the racking crank. The racking crank should be blocked by the
POSITIVE INTERLOCK. Trip the breaker and install the racking
crank and rack the breaker toward the connected position. The
spring discharge interlock will discharge the closing spring,
during the first five turns, usually between the third and fourth
if the closing spring is charged. The contacts of the circuit
breaker should remain open. (If adjustment is required see
MECHANICAL ADJUSTMENTS sections 16.7 and 16.8.) Rack
the breaker into the CONNECTED position and charge the
closing spring. If secondary control power is available the
closing spring will charge automatically. Assure that the
breaker is in the OPEN condition.
Rack the breaker from the CONNECTED back to the
DISCONNECT position. During the first three turns, the spring
discharge interlock should discharge the closing spring and
the breaker contacts should remain OPEN. (If adjustment is
required see MECHANICAL ADJUSTMENTS sections 16.7 and
16.8.)

17
SECTION 11—Maintenance
WARNING: BEFORE ANY MAINTENANCE WORK IS
PERFORMED, MAKE CERTAIN THAT ALL CONTROL
CIRCUITS ARE DE-ENERGIZED AND THAT THE BREAKER IS
REMOVED FROM THE METALCLAD UNIT. DO NOT WORK
ON THE BREAKER OR MECHANISM WHILE IT IS IN THE
CLOSED POSITION WITHOUT TAKING PRE- CAUTIONS TO
PREVENT ACCIDENTAL TRIPPING. DO NOT WORK ON THE
BREAKER WHILE THE CLOSING SPRING IS CHARGED
UNLESS IT IS SECURED IN THAT POSITION BY THE
CLOSING-SPRING GAG.
11.1—General
PowerVac®circuit breakers have been designed to be as
maintenance-free as practicable. They include features such
as sealed vacuum interrupters and long-life synthetic greases
which contribute to many years of trouble-free performance
with a minimum amount of maintenance.
11.1.1 Interrupter
The interrupter used in this breaker is a reliable, clean
interrupting element. Since the contacts are contained in a
vacuum chamber, they remain clean and require no
maintenance at any time. The metallic vapors eroded from the
contact surfaces during high current interruption remain in the
chamber and are deposited on metal shields thus insuring a
high dielectric value of the vacuum and the walls of the
interrupter.
11.1.2 Trouble Reporting
Although all reputable manufacturers design their products to
perform satisfactorily with a minimum of problems, the IEEE
Switchgear Committee, an organization of both users and
manufacturers, recognize the need for a common trouble
reporting format. A reproducible copy of this form is included
inside the rear cover of this book and is recommended for use
with any manufacturer’s circuit breakers.
The intent is for each maintenance organization to keep
specific problem files with this information documented.
If the problem is serious or repetitive, a summary should be
sent to the appropriate manufacturer for action. The level of
detail included on the form is considered very desirable so
that the manufacturer’s investigator may more thoroughly
understand and solve the reported problem.
11.2—Service Conditions
The frequency of required maintenance depends on
the severity of the service conditions of the switchgear
application. If the service conditions are mild, the interval
between maintenance operations may be extended to 10
years or 2,500 no load or 200 normal load switching
operations. Mild service conditions are defined as an
environment in which the switchgear is protected from the
deleterious effects of conditions such as:
Salt spray
Changes in temperature that produce condensation
Conductive and/or abrasive dust
Damaging chemicals and fumes
Vibration or mechanical shock
High relative humidity (90%)
Temperature extremes (below –30°C or above +40°C)
11.3—Fault Interruptions
The erosion rate of the primary contacts in the vacuum
interrupters is very low for normal load switching operations.
However, fault current interruptions at or near the breaker
rating may result in appreciable contact erosion. With frequent
fault interruptions it is necessary to perform maintenance
based on the number of interruptions. After 15 full fault
interruptions the following should be performed:
1. Contact erosion check.
2. Wipe and gap check
3. Vacuum interrupter integrity test.
11.4—Contact Erosion
Check in the breaker-closed condition per PRIMARY
CONTACT EROSION section 8.1. When erosion reaches
.125 inch, the interrupter should be replaced.
11.5—Transfer Finger Wear
With the breaker open, examine the moving contact rod
projecting below the transfer fingers (10, Figure 6). Wipe
off the lubricant in order to see the metal surface condition.
The finger locations should present a burnished silver contact
without copper appearance at more than one location. If
copper is visible at more than one location per pole or the
silver plating is torn, the interrupter assembly should be
replaced. Re-lubricate with 0282A2048P009.
11.6—Mechanism
Check all items covered in INSTALLATION and readjust or
tighten hardware as required. Lubricate as recommended
under LUBRICATION.
11.7—Primary Insulation Parts
Using dry, non-linting cloth or industrial-type wipers, clean
accessible insulation surfaces on the interrupter supports
and operating rod insulators. In service locations where
contamination is heavy or external flashovers, have occurred
during interrupter high-potential testing, remove the
interrupter assemblies per the procedure in REPAIR AND
REPLACEMENT and clean the inside surfaces of the
interrupter supports and the outer insulation surfaces of the
interrupters. Removal and reassembly of interrupter
assemblies will normally not require adjustment due to the
design of the interrupter operating rod insulator connection.
They should be returned to the same phase location from
which they were removed.

18
11.8—Lubrication
Proper lubrication is important for maintaining reliable circuit
breaker performance. The ML-20 mechanism uses bearings
which have a synthetic lining in some locations. These
bearings do not require lubrication to maintain low friction, but
lubrication does not harm them and oiling lightly is
recommended. Sleeve bearings are used in some linkage
locations and needle or roller bearings are used for low friction
on trip shaft and close shaft.
Bearings are lubricated during factory assembly with grease
and oil, but all lubricants have a tendency to deteriorate with
age. Providing a fresh lubricant supply at periodic intervals is
essential to proper breaker operation, especially where
frequent operation may have forced lubricant out of the
bearing surfaces. Apply a few drops of light synthetic machine
oil such as Mobile 1 at each bearing. Apply a coat of
0282A2048P009 grease on the four corners of the closing
spring guide where it enters inside the spring.
Metal-to-metal contact surfaces should be cleaned and
lubricated with 0282A2048P009 grease to provide cleanliness
and prevent oxidation.
Electrical primary contact surfaces also require periodic
lubrication to inhibit oxidation and minimize friction. At each
inspection and maintenance interval, do the following:
1. Wipe clean and coat lightly with grease
(0282A2048P009) all silvered primary contact surfaces
such as the movable contact rod of the interrupter and
the primary disconnect fingers.
2. Clean and coat lightly with grease the pins of the
secondary disconnect coupler.
11.9—Recommended Maintenance
The following operations should be performed at each
maintenance check:
1. Perform a visual inspection of the breaker. Check for
loose or damaged parts.
2. Perform slow closing operation described under
MECHANICAL CHECKING AND SLOW CLOSING.
3. Check the erosion indicator and the wipe and gap as
described under DIMENSIONAL CHECKS.
4. Perform the vacuum interrupter integrity test as
described under ELECTRICAL CHECKS.
5. Lubricate the breaker operating mechanism as described
under LUBRICATION.
6. Check the electrical operation using the test cabinet (if
available) or the test position in the metalclad switchgear.
CAUTION: REPEATED OPERATIONS AT A RATE EXCEEDING
TWO PER MINUTE MAY CAUSE CHARGING MOTOR
OVERHEATING AND SUBSEQUENT MOTOR FAILURE.
7. Examine the movable contact rod of the vacuum
interrupter. With the breaker open, wipe the lubricant off
the rod and examine the silver surface. The rod should
have a burnished appearance without copper appearing
through the silver. If copper is visible at more than one
location per pole, or if the silver plating is torn, the
interrupter assembly should be replaced. Re-lubricate
movable contact rod with 0282A2048P009 grease
8. If desired, perform the additional electrical tests (Megger,
Primary and Secondary High Potential, and Primary Circuit
Resistance). See ELECTRICAL CHECKS.
Nominal Charge Motor Close Coil Trip Coil
Control
Voltage Part No. Range Part No. Range Part No. (5 cycle) Part No. (3 cycle) Range
48 VDC 0177C5050G009 36-56 0209B8103G008 38-56 0209B8104G001 0209B8104G0
01 28-56
125 VDC 0177C5050G007 90-140 0209B8103G009 100-140 0209B8104G002 0209B8104G0
07 70-140
250 VDC 0177C5050G008 180-280 0209B8103G010 200-280 0209B8104G003 0209B8104G0
0…6 140-280
120 VAC 0177C5050G047 104-127 0209B8103G011* 104-127 0209B8104G004** N/A (Cap. Trip)
104-127
240 VAC 0177C5050G008 208-254 0209B8103G012* 209-254 0209B8104G004** N/A (Cap. Trip) 208-254
*With rectifier
**With Capacitor Trip Module
Table 1. Control Devices and Voltages

19
SECTION 12—Timing
Timing and speed checks are optional and also depend on the
level of maintenance performed. Generally these tests are not
required for normal maintenance. If a new mechanism has
been installed or extensive repair, replacement or major
disassembly has been performed, it is recommended that
these tests be performed.
To determine contact velocity, a travel recorder and or an
oscillograph are required. Optional, travel recorder linkage can
be obtained through your local GE Sales Office by ordering
part number 0144D1235G002. A typical travel trace and
interpretation are shown in Figure 11.
Timing may be checked by monitoring control circuit voltage
and using no more than six volts DC and one ampere through
the vacuum interrupter contact to indicate closed or open
condition. Typical time ranges vary with coil voltage, but
nominal values are:
Initiation of trip signal to contact parting
5 Cycle Breaker 32-45Milliseconds
2 Milliseconds Maximum Pole Spread
Initiation of close signal to contact closing
45-75 Milliseconds (DC Control Voltage)
35-65 Milliseconds (AC Control Voltage)
2 Milliseconds maximum pole spread
Trip-free operation maybe checked by applying a simultaneous
close and trip signal, and a minimum re-close operation may
be checked by tripping a charged breaker open while
maintaining a close signal.
Instantaneous re-close time* 85-140 Milliseconds.
*Time from application of trip signal until breaker contacts
re-close.
Figure 11 Sample operating speed graphs
* For breakers equipped with an opening dashpot,
there is virtually no overtravel or rebound.

20
SECTION 13—Opening and Closing Speed
The opening speed is modified by moving the spring adjusting
nuts on the opening spring assemblies. A change in opening
speed affects the closing speed. Reference Figure 12.
The operating speeds for a 5 cycle breaker are as follows:
Operation
OperationOperation
Operation Feet Per Second
Feet Per SecondFeet Per Second
Feet Per Second
Open 4.3 - 5.6
Close 2.6 – 3.9
V.I. STOP CENTER PHASE
Figure 12 Contact gap adjustment