The document provides information about a product training course on medium voltage panels, vacuum circuit breakers, and contactors ranging from 3.3kV to 33kV. It covers the history of switching technology from oil to vacuum, the advantages of vacuum switching, applications of vacuum circuit breakers, components and design features of switchboards, and operational procedures for applying and removing cable earths.

1. PRODUCT TRAINING COURSE
Routine Maintenance & Service Instructions
for Medium Voltage panels, vacuum circuit
breakers and contactors 3.3kV to 33kV.
For Hands-on, in-Situ Training...
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OTHER THAN THE BORROWERS AGREEMENT THAT IT SHALL NOT BE REPRODUCED,
COPIED, LENT OR DUPLICATED, DIRECTLY OR INDIRECTLY, NOR USED FOR ANY
PURPOSES OTHER THAN THAT FOR WHICH IT WAS SPECIFICALLY FURNISHED.
THE APPARATUS SHOWN ARE COVERED BY PATENTS.

2. Beginning of 1900’s
First research is done by Siemens in current interruption under oil &
research into insulating mediums such as vacuum, solutions & gases
1960’s - Oil circuit breakers are in full manufacture, vacuum switching research
& development successful, gas research & development continues
First successful industrial manufacturing of the vacuum interrupter
Further research into flow and electro-magnetic arc quenching in
developing safer & more effective methods inside different mediums
1970’s Siemens develops concept of 3phase synchronised switching for
vacuum interrupter technology, with application of a stored energy
spring charge design derived from principles developed from already
existing Siemens designs of operational pneumatic, compressed air
type and spring loaded energy type switchgear mechanisms, as already
operational with oil, air-blast, expansi’en & other switchgear, gas
research is onto “SF6”
1977 First vacuum circuit-breaker manufactured by Siemens in Germany
9 1993 Siemens presents the world’s first low maintenance vacuum circuit-
breaker.
1998 Siemens combines the vacuum switching principle and disconnecting
function mechanism for Earth switch in one module “NXACT”
2

3. THE ADVANTAGES OF SWITCHING UNDER VACUUM
Constant dielectric
Hermetically sealed vacuum interrupter keeps out all environmental effects
No gas decomposition products in vacuum
Constant contact resistance
In vacuum, contacts cannot oxidize
The very small resistance is maintained throughout the contact life
High total current switched
Since contact erosion is small, rated normal current can be interrupted up to 30,000 times
and rated short-circuit breaking current up to 100 times (and more)
Economic advantages
Vacuum interrupters are maintenance-free
Modern vacuum circuit-breakers are also maintenance-free, e.g. Siemens type 3AH
3

4. ELECTROMAGNETIC ARC DIFFUSION IN A
Comparison of the arc quenching principles Vacuum and SF6
Performance of the mentioned quenching medium
Poor Good Very good Excellent
Criterion SF6 Vacuum
Risk of fire and explosion
Inspection of the quenching medium
Reliability in event of a leakage
Lifetime
Range of breaking capacity
Switching surges
Dimensions
Cost of maintenance
Performance of the mentioned quenching medium
Poor Good Very good Excellent
Criterion SF6 Vacuum
Risk of fire and explosion
Inspection of the quenching medium
Reliability in event of a leakage
Lifetime
Range of breaking capacity
Switching surges
Dimensions
Cost of maintenance
4

5. Siemens Vacuum Circuit-Breakers can be used:
- for all medium voltage applications
• Capacitors
• Arc furnaces
• Shunt reactors
The most important applications are the switching of:
• Transformers in distribution networks
• Cables and overhead-lines
• Motors
• Generators
5

6. INTRODUCTION TO THE SWITCHBOARD & ITS COMPONENTS
WARNING
This equipment contains hazardous voltages and mechanical parts which move at high speed
and may be controlled remotely.
Non- observance of the safety instructions can result in severe personal injury or property damage.
Only qualified personnel should work on or around this equipment after becoming thoroughly
familiar with all warnings, safety notices, and maintenance procedures contained herein.
The successful and safe operation of this equipment is dependent on proper handling, installation,
operation and maintenance.
6
INTRODUCTION
The Siemens 8BF switchgear is a range of type tested metal clad medium-voltage indoor switchgear for
rated voltages between 3.3 to 24KV. Within the 8BF Family there are two types of panels;
The 8BF00 type is a 600mm wide panel rated up to 12KV, 800A to 1250A and with a short circuit and
internal arc proof rating of 20KA to 31.5KA.
The 8BF01 type panel is 800 mm wide and is rated up to 24KV, 800A to 3150A and with a short circuit and
internal arc proof rating of 20KA or 40KA.
The 8BF switchgear range is typically used for switching duties in mining, primary reticulation and
industries.

7. DESIGN FEATURES
Metal partitions, subdivide each cubicle into; a bus bar compartment, a switching device, circuit
breaker or vacuum contactor compartment, a MV cabling compartment, and a LV equipment and
relay compartment. Circuit-breakers can be used in practically any system design.
7
Pressure release devices
The compartments are each fitted with safety screens for deflection of ionized gases, and pressure
relief flaps for explosive release of any ionized gases. All primary circuit compartments are fitted with
pressure relief flaps for exhausting hot ionized gasses in the event of internal arcs, and are fitted
with safety screens to direct the gasses upwards, providing total safety to personnel standing in
close proximity of the switchgear during fault conditions.
The internal compartment also has protective covers “flaps” where the contact arms of the circuit
breaker enter the busbar and cable compartments. The purpose of these is to enable safe lock outs
to both interconnecting compartments when the circuit breaker has been removed.
Incomers and Tie-breakers are usually fitted with an additional spring operated explosion release
flap. This flap usually remains open during normal operation, as it then acts as an additional cooling
vent, allowing a passage for a convectional air flow. When an explosion occurs the vent is shut
automatically by the escaping air flow and will remain closed. This will protect the operator and also
cut off the immediate supply of oxygen into the compartment, thereby eliminating a possibility of a
fire hazard.

8. BUSBAR DIFFERENCES BETWEEN 8 BF 00 AND 8 BF 01.
8

9. LV Control section MV Circuit breaker section
Cubicles are of a robust welded
assembly with the LV compartment
mounted above the circuit breaker
compartment. Each compartment is
independent and is separated by
earthed sheet metal. The circuit
breaker compartment houses the
positively driven bus bar and cable
shutters, which are pad-lockable. The
padlock able cable earth switch is
housed in the bottom of the cable
compartment but operated from the
circuit breaker compartment.
The bus bar compartment houses the
three main bus bars arranged in
trefoil.
The MV cabling compartment,
housing the cable earth switch,
current transformers and cable
connections is accessed from the
rear after removal of a bolted cover.
The LV compartment houses control,
metering, protection, switching and
indication equipment.
Circuit breaker compartment, with cable and Bus bar cable shutters
9

10. 10
LV control panel door with control’s and LED
indications, metering equipment, Test blocks,
and other customer requirements
Depending on the type of panel the following
accessories are supplied: earth switch
operating handle spring recharge handle
racking handle
Cable earth switch handle
Control cubicle panel door
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Circuit breaker spring charge lever
Racking Handle

11. OPERATIONAL PROCEDURES - FOR CABLE EARTH
WARNING!
Before applying any earths it is important to make sure the circuits are isolated and that the operator
has carefully read the relevant earth switch operating instructions, usually found stuck to the panel
near the earth switch
11
• Withdraw the circuit
breaker from the
cubicle,
• Remove the earth
switch padlock,
• Insert the earth
switch handle into
the key slot,
• Close the earth
switch,
PROCEDURES:
To apply the
Cable Earth:
NOTE:
With the earth switch
closed, the circuit breaker
cannot be inserted into
the switch cubicle as the
interlocking bar obstructs
its movement.
.
To remove the
cable earth:
• Remove the earth
switch padlock,
• Depress the earth
switch release
leaver whilst
opening the earth
switch,
• Remove the earth
switch handle.
• Padlock the earth
switch
NOTE:
The circuit breaker can
now be inserted into the
switch cubicle.

12. Cable and Bus bar earth trucks
In our quest to improve the safety of our equipment we now offer Earthing circuit breaker
trucks for bus bar and incomer Earthing applications.
The bus bar earth truck is recognizable by its red front shield and contact arms only on the
topside of the circuit breaker.
The cable earth truck is recognizable by its yellow front shield and contact arms only on the
bottom side of the circuit breaker.
The operation of the bus bar and cable earth trucks would be dedicated to the specific
boards, and the correct interlocking procedures for the specific board would have to be strictly
followed.
Bus bar and cable Earth Trucks, identifiable by different coloured front shields
12

13. Cable Earth Truck
Note: Contact fingers
located at the bottom
WARNING !
This equipment contains a
stored energy type spring
mechanism. The Kinetic force
of the spring when charged is
+/- 1Ton /per cm2
“DANGER”,
as it can be released by
accidental contact with the
mechanism.
Ensure that the Spring is
discharged by inserting the
handle into the front racking
lever, turning it to the racked
“in” position. Standing clear
and away from moving parts,
switch the mechanism “on”
and “off” until there’s no
further response from the
mech. Take care when working
on this apparatus, as all
mechanical parts move at very
high speeds & can cause
severe property damage &
disabling personal injuries.
Only qualified personnel
should work on or around this
equipment after becoming
thoroughly familiar with all
warnings, safety notices, and
maintenance procedures
contained herein.
The successful and safe
operation of this equipment is
dependent on proper handling,
installation, operation and
maintenance.
Bus bar Earth Truck
Note: Contact fingers
located at the top
13

14. 14

15. 15

16. 16
The Auto bonnet type VT fixture design
The VT itself is firmly secured into the top
panel VT box and this is secured to the panel
by hinge like spring loaded counter-pressure
arms. This type of design makes it possible to
rack the VT out of circuit, and to lock it out in
that position or for easy replacement in a case
were this should ever be necessary.
It is also beneficial for testing procedures such
as Pressure testing the bus bar’s or cable’s
within the panel.
The connection points of the VT in the base of
the VT box (which remains fixed to the top of
the panel compartment) are all spring pin point
loaded. These are placed under pressure
against the contact points when the VT is
closed. The advantage of this is that once
closed there are no open wire or cable points
exposed, as the VT can only operate in the
closed and insulated position.
Bus bar and Cable mounted Voltage Transformers (VT’s)
The following pictures indicate the panel cubicle mounted VT. This unit is mounted as shown on top
of the incomer cubicle. It is connected with a special cable guided compartment, to either the top of
the incomer points (bus bar VT) or to the live cable side bottom point of the incomer (Cable VT).
In most cases the bus bar connected VT is a favourable norm, as in this type of arrangement it is
possible to also isolate the VT output voltage by just switching the Incomer off. This is a design
feature that is usually decided on by the client according to preference.

17. ! ! ! - SAFETY PROCEDURES - ! ! !
WARNING
This equipment contains hazardous voltages and mechanical parts which move at high speed
and may be controlled remotely.
Non- observance of the safety instructions can result in severe personal injury or property
damage.
Only qualified personnel should work on or around this equipment after becoming thoroughly
familiar with all warnings, safety notices, and maintenance procedures contained herein.
The successful and safe operation of this equipment is dependent on proper handling,
installation, operation and maintenance.
SAFETY FIRST !
The following Safety guidelines must be observed by the operator, or maintenance electrician, before
performing routine maintenance and service on switchgear, to ensure that the procedure is performed
correctly within the Safety regulations. The work is to be undertaken only by qualified electrical Artisans
or technicians who are familiar with the operation and maintenance of the equipment in question, and
are aware of all possible dangers involved with such procedures.
SAFETY PROCEDURES FOR FIXED MOUNTED CIRCUIT BREAKERS / CONTACTORS.
Before commencement of any work the Artisan / Technician must ensure that the equipment
concerned has been switched OFF and is ISOLATED on both sides and that the FEEDER to the
SUPPLY side has been LOCKED OUT.
PERSONAL PROTECTIVE EQUIPMENT MUST BE WORN DURING SWITCHING / TESTING / ISOLATION OR
EARTHING OF EQUIPMENT!!!
* (IN ACCORDANCE WITH LEGISLATION & ALL SAFETY REGULATIONS) *
The equipment must then be proven ‘Safe’ with the use of a Phasing stick for (H.V.), and Voltmeter for
(L.V.), by measuring each phase to the earth bar, or between phases to confirm that no voltage is
present on both the Supply and Load sides. Special 1 into 3 Earthing leads, capable of carrying the
maximum rated earth fault current, are to be used to additionally Isolate and earth the bus bars at both
the Supply and Load ends.
The Artisan / Technician is to ensure that the circuit breaker (if it is of the stored energy type) is not still
charged and ready for operation, as the closing operation could accidentally be triggered whilst servicing
the circuit breaker, with possible devastating effects. If the breaker is still charged, remove the electrical
plug connector and mechanically push the On and Off buttons in sequence several times until there is no
further response from the circuit breaker.
Once the Artisans / Technician's are certain that the equipment is safe, the above requirements have
been met, and a work permit has been issued, the service and maintenance procedures may
commence.
17

18. SAFETY PROCEDURES FOR WITHDRAWABLE CIRCUIT BREAKERS / CONTACTORS.
Before commencement of any work the Artisan / Technician must ensure that the equipment
concerned has been switched OFF and is SAFE to be removed from the cradle or cubicle.
PERSONAL PROTECTIVE EQUIPMENT MUST BE WORN DURING SWITCHING / TESTING / ISOLATION OR
EARTHING OF EQUIPMENT!!!
* (IN ACCORDANCE WITH LEGISLATION & ALL SAFETY REGULATIONS) *
The Artisan / Technician is to ensure that the circuit breaker (if it is of the stored energy type) is not still
charged and ready for operation, as the closing operation could accidentally be triggered whilst servicing
the circuit breaker, with possible devastating effects. If the breaker is still charged, remove the electrical
plug connector and mechanically push the “On” and “Off” buttons in sequence several times until there is
no further response from the circuit breaker.
Once the Artisans / Technician's are certain that the equipment is safe, the above requirements have
been met, and a work permit has been issued, the service and maintenance procedures may
commence.
TECHNICAL SPECIFICATIONS OF THE EQUIPMENT.
Each circuit breaker and panel type is differentiated by its type number or lettering. These are
important items that must be observed before any work commences on the apparatus. As this
information will detail the particulars of the equipment that is to be serviced. There are many
types of equipment and the specifications for these various types may differ considerably from
one another. So care should be taken before attempting to service any equipment that we are
familiar with what type of equipment we are dealing with, the dangers of such equipment and the
methodology of the service requirement for such equipment.
Standard circuit breaker Name-plate representation
Basic type
Rated voltage
Rated short circuit
breaking current
Rated normal current
Note: In the event of any uncertainties or
design code queries at a time of placing an
urgent order for emergency spare parts; just
state the type digit, the design code digit and
the serial number of the equipment. This info
will enable the operator of our 24hr Hotline to
source any spares for immediate delivery
locally, or within 24hrs abroad.
18

19. Standard specifications:
The 3AH1 vacuum circuit-breakers comply with the standards of IEC 56, IEC 694, BS 53111
and DIN VDE 0670. The V-breakers 3AH1 for 15 kV rated voltage meet the requirements of the
American standards ANSI C37 with respect to their insulating capacity.
The following circuit breaker Types are utilised by Escom in the following Stations:
Vygeboom – Types: 3AH1055-2; 3AH1054-4; 3AH5115-2
Bosloop – Types: 3AH1056-2; 3AH1056-4
Wintershoek – Types: 3AH1056-2; 3AH1056-4
Nooitgedacht - Types: 3AG1441-1 & 3AH Types as above
Ambient temperature, humidity and load-ability.
The 3AH1-5 V-breakers are designed for the normal operating conditions laid down in the standards.
Permissible ambient temperatures :Maximum value = +40 °C
Average over a period of 24 hours =
+35 °C Minimum value= – 5 °C Permissible atmospheric humidity, Relative humidity, 24 hour mean
= max. 95% Relative humidity, 1 month mean = max. 90%.
Under these conditions condensation may occasionally occur. The rated normal currents listed in the type
designated tables as shown in the different catalogues, were laid down for 40 °C ambience in accordance
with DIN VDE / IEC. Use, under conditions other than normal is possible with certain measures that can
be implemented on request.
The maximum permissible load current as a function of the 3AH - V- breaker ambient temperature have
been plotted for your convenience, in each of the breaker’s companion manuals. The load currents
indicated apply to open-type switch-gear. For metal-enclosed switchgear, these must be identified, as
specified by their individual switchgear manufacturer’s Operating Manuals.
19

20. Site altitude
The insulating capacity of an insulation in air decreases with increasing altitude as a result of changes in
the air density. Standards promulgated by DIN VDE, IEC and other disregard this decrease in insulating
capacity for altitude of up to 1000 m, i.e. the decrease of approximately 9 % at this altitude is still
permissible.
The standards provide no guideline for altitudes of more than 1000 m with respect to insulation ratings;
they leave this up to an agreement between manufacturer and user. Our own recommendation is as
follows:
Since this method used for rating insulation up to altitudes of 1000 m has proved to be satisfactory, it
should also be applied to higher altitudes. The altitude correction factor should therefore be based on
the insulating capacity at 1000 m, which is lower by 9 % (corresponding to 0.91) than the capacity at sea
level.
The following expression thus applies for selection of the equipment rated withstand voltage to be
selected:
Reference: Circuit breaker operating manual
20

21. Description of Terms commonly used in circuit breaker technology
Closing time = the interval of time between the initiation of the closing operation and the instant
when the contacts touch in all poles.
Opening time = the interval of time between the initiation of the opening operation and the instant
when the contacts separate in all poles.
Arcing time = the interval of time between the instant of the first initiation of an arc and the
instant of final arc extinction in all poles.
Break time = the interval of time between the beginning of the opening time of a circuit-breaker
and the end of the arcing time.
Close-open time = the interval of time ( in a make-break operating cycle) between the instant when
the contacts touch in the first pole in the closing process, and the instant when the
arcing contacts separate in all poles in the subsequent opening process.
Switching duties = The operating mechanisms of the 3AH1 circuit-breakers are suitable for rapid
auto-reclosure. Breakers for a rated short-circuit breaking current of 40 kA are, at
rated data levels, suitable for rapid load transfer; up to 31.5 kA they can also be
used for rapid auto-reclosure.
Two Golden Rules before opening the circuit breaker / contactor front cover
21
C/B STATUS INDICATOR
ΙΙΙ - ON
Or
ΟΟΟ - OFF
= Closing Spring Discharged
= Breaker is Condition – “OFF”
(Safe to open front cover)
= Closing Spring Charged
= Breaker in Condition – “ON”
(NOT !!! Safe)
- with either of the above conditions
do NOT remove the front cover !

22. 22
SERVICING GUIDELINES
Cleaning: Clean as required and at accessible intervals of +/- 6 months.
Re-greasing: Oiling and re-greasing of the mechanism need only be done after 10000 operations or every 5
years. This is, however, dependant on the status of the lubricants as derived from the annual inspection, as
environmental factors could cause faster lubricant deterioration.
Contact sys: Only to be checked every 10000 operations.
Vacuum: Vacuum checks should be done annually during a routine service inspection.
Interrupters: Vacuum Interrupters need only be replaced after 30000 operations or as required
Major Service is only required after 30 000 operations or approximately 10 years. This also depends on the
type of breaker and the environmental factors, and performance of regular service inspections and cleaning.
If no maintenance or inspections have been performed from time of installation, a major service is
recommended, for Safety reasons, after 5 years.
To mechanically operate a vacuum circuit breaker:
Conditions to be satisfied:
• Ensure the racking handle is in the “racked in” position,
• Ensure the interlock lever is in the interlock or locked position,
• Charge the closing spring by inserting the hand crank into the spigot shaft and rotating clockwise until
the closing spring is charged, a loud click sound will be heard and the spring position indicator
indicates charged,
• Depress the black close push button. The indicator will indicate “I” circuit breaker closed,
• To trip, depress the red trip button. The indicator will indicate “O” circuit breaker open.
To move a circuit breaker from the isolated or test position into the service or racked in position in
an 8BF01 panel with positive racking the procedure is as follows:
• The circuit breaker must be open or in the tripped state,
• Move the racking lever to the racked out position,
• Insert the LV control plug and lock the retaining clip,
• Insert the circuit breaker trolley into the panel until the front shield is approximately 15mm from the
final insertion point,
• Move the racking lever form the racked out to the racked in position to fully engage the trolley into the
panel.
To withdraw or rack out the circuit breaker in a 8BF01 panel
• The circuit breaker must be open or in the tripped state,
• Move the racking lever to the racked out position,
• Release the expulsion interlock by operating the foot pedal,
• Withdraw the circuit breaker until the main contacts are isolated and the breaker is in the test position,
• Disconnect the LV control plug and withdraw the circuit breaker completely from the panel.
To move the circuit breaker into the test position:
• The circuit breaker must be open or in the tripped state,
• Move the interlock lever to the free position,
• Insert the circuit breaker trolley into the panel until the top shoot bolts line up with slots in the front
housing,
• Insert the LV control plug and lock the retaining clip,

23. MAINTENANCE PROCEDURES FOR VACUUM SWITCHGEAR.
The vacuum circuit breakers or contactors generally require little maintenance. The work to be done to
ensure constant readiness for operation depends on the operating conditions and local circumstances.
Under normal circumstances, however, a visual maintenance inspection on the state of the circuit breaker
or contactor is recommended to be done annually.
1. ISOLATING THE VACUUM CIRCUIT BREAKER / CONTACTOR
The Artisan/Technician is to ensure that the circuit breaker or contactor is switched OFF, and ISOLATED.
If the breaker is of the stored energy type, the circuit breaker mechanism must be discharged.
For breakers with automated motorised charging, first remove the Plug connector. This will disconnect the
supply from the auto recharging circuit and charging motor of the breaker operating mechanism. Then
simply discharge the mechanism by switching the breaker “on” and then “off” again. As an additional
precaution, attempt to switch the breaker “on” and “off” again. There should be no further response from
the mechanism. It is now safe to work on the internal components once this condition has been achieved.
Once the Artisan / Technician is certain that the equipment is safe, all the above safety requirements have
been met, and a work permit has been issued, the service and maintenance procedures may commence.
2. ASESSMENT OF SERVICE INTERVALS FOR THE CIRCUIT BREAKER / CONTACTOR
The time and scope of work to be done is dependant on the following factors:
1. The operating time
2. The number of mechanical operating cycles
3. The number fault trip operations
The maintenance work below refers mainly to the breaker or contactor operating mechanisms. The
vacuum interrupters are maintenance free until they reach the number of permissible operating cycles.
It is, however, advised that certain interrupter criteria be checked and inspected as discussed later in
the document.
23

24. 3. SERVICING OF THE SWITCH-TRUCK AND SWITCHBOARD
Prior to beginning with any maintenance and service work the responsible person must make sure that the
equipment to be worked on is isolated and locked out according to recognized safety procedures. Isolate the
control supply in the LV compartment. Rack out the circuit breaker or vacuum contactor and remove the LV
control plug. Close the cable earth switch and padlock the earth switch, cable and bus bar shutters.
FIRST LINE MAINTENANCE AND SERVICE: THE CIRCUIT BREAKER / CONTACTOR TRUCK
Before beginning to service a Siemens vacuum circuit breaker truck discharge the closing spring manually
and remove all covers on the circuit breaker truck. Visually inspect the equipment for warn or damaged
components;
Counter Breaker indication Gearbox
Closing coil Tripping spring Closing spring
Closing button Tripping button S1 auxiliary contacts
Spring charge motor Contact fingers Vacuum interrupters
Tripping coil
Re-lubricate the operating mechanisms with an approved Siemens lubricant. If a counter is fitted record the
reading. This information gives an indication to the wear on the main interrupters. If the counter exceeds the
maximum number of make or break operations for that particular breaker the nearest Siemens representative
should be informed.
To check the main contact wear, a marking is provided on the lower interrupter support. If the indicator is
above the red mark when the circuit breaker is closed it indicates excessive contactor wear and the nearest
Siemens representative should be informed. If it is suspected that a vacuum interrupter has lost its vacuum a
high voltage test needs to be performed. Visually check that the carbon brushes of the spring charge motor
are in good condition. Check the free movement of the closing and tripping coils. To check the latching of the
operating mechanism the closing spring is charged manually and depressing the black close push button
closes the breaker. The breaker should now be latched in the closed position. Depressing the red trip button
to verify the mechanical tripping operation now trips the breaker.
Wipe down and clean the circuit breaker truck. Replace all circuit breaker covers. Move the circuit breaker
into the test position. To check the electrical close and trip operation of the circuit breaker, re-instate the
control voltage and electrically operate the breaker. When complete, isolate the control voltage and rack out
the circuit breaker.
Check the finger contacts for signs of over heating, contact
tightness and contact alignment and lubricate with an
approved Siemens lubricant. If the contact tightness or
contact alignment needs adjustment the nearest Siemens
Representative should be informed. Re-torque all the bolts
on the circuit breaker arms according to the Siemens
specifications.
FIRST LINE MAINTENANCE AND SERVICE: THE SWITCHBOARD
Check free and smooth operation of the shutter mechanisms, clean and lightly lubricate the shutter operating
rods. Visually inspect spouts for cracks, tracking and corrosion. Clean the circuit breaker compartment.
Check correct operation of the earth switch making sure the cable is isolated before applying the earth
switch. Check the correct racking in and out of the circuit breaker truck.
Visually inspect the bus bar and cable compartments for dust contamination, deterioration of insulation and
hot connections. Wipe down the insulators and clean the compartments.
Visually inspect the cable earth switch for correct operation and contact penetration. Lubricate the operating
mechanisms and contacts with an approved Siemens lubricant.
Visually inspect that the explosion flaps are in a good order and report any defective flaps.
24

25. 4. FIRST LINE MAINTENANCE FOR VACUUM CIRCUIT BREAKERS
4.1 INSPECTION OF THE VACUUM INTERRUPTERS
Description of the Vacuum Interrupter Pole Assembly
Description Construction The vacuum circuit-breaker consists of the mechanism housing (60.) , the 3-pole
assemblies (19.) with vacuum interrupters (30.), cast-resin post insulators (16.1 and 16.2), struts (28) and of
the operating rods (48.) with contact pressure springs (49.). Each of the three pole assemblies (19.) is
supported by two Cast-resin post insulators (16.1 and 16.2), which are bolted to the pole plate (15)
respectively.
25

26. 4.2 THE POLE ASSEMBLY
The pole assembly (19.) consists of the upper interrupter support (20.) with the upper terminal (27.) , the
vacuum interrupter (30.) , the lower interrupter support (40.) with the lower terminal (29.), the clamp (29.2.)
with the flexible con- nector (29.1.) and the angled Lever (48.6.). The centring piece (28.1.) and the struts
(28.) relieve the vacuum interrupters of external forces see (Fig. below).
4.3 The Vacuum Interrupter
The basic construction of the vacuum interrupters for the 3AH4 vacuum circuit-breaker is shown in the
sectional view in Fig. 2/5. .;
Depending on its type, the vacuum interrupter (30.) is fixed to the upper interrupter support (20.). The
arcing chamber (33.) is located between two ceramic insulators (32.). The fixed contact piece (31.) is
connected directly with the housing. The moving contact piece (36.) is fixed to the terminal bolt (36.1) and
is located centrally in the guide (35.). The metal bellows (34.) forms the vacuum-proof connection to the
interrupter housing.
The vacuum interrupters fitted in the 3AH vacuum circuit- breakers are type tested and -approved in
accordance with the X-ray regulations of the Federal Republic of Germany. They conform to the
requirements of the X-ray regulations of January 8, 1987 (Federal Law Gazette Page 144) § 8 and Annex
III Section 5 up to rated short-time AC voltage stipulated in accordance with DIN VDE/IEC.
26

27. 4.4 Checking the contact System of the vacuum Interrupters
The contact system is subject to wear by both contact erosion and by compression of the contact pieces and
the guide bolts. Note: With some earlier 3AG types, the moving terminal bolt (36.1) of the vacuum interrupter
(30.) is provided with the check marking (13.9). As long as the white dot marking is wholly or partially visible
when the 3AG vacuum circuit-breaker is closed, the shortening of the contacts is within the permissible
range. With the newer 3AH types, the indicator for checking the contact wear is located on the side of the
lower Pole assembly of the moving contact rod housing. This is either indicated by a sticker marking showing
a red line. This sticker is fixed to the poles and indicates the initial closed contact state position, after
assembly and testing as the circuit breaker, before it was released from the factory
Legend
13. Check marking
30 Vacuum interrupter
36.1 Drive and terminal bolt
Checking the contact wear
Each interrupter is pre-manufactured with a white punch mark,
or a marking sticker, which can be found in the keyway of the
moving contact shaft, or the side of the lower contact pole
housing. With the interrupter in the closed position, this white
dot must still be visible. With intensive switching this dot will
slowly move into the interrupter, as the contacts become worn.
In the case where this is indicated by a red line sticker, the
original position marking will move away from the closed
position line. Once this dot / line moves further and further into
the interrupter, or apart, the interrupter should be replaced just
before the dot disappears completely, or the line spacing
becomes excessive. An alternative, and by far more accurate
method of determining the contact wear, is to individually
measure each interrupters difference between the open and
closed positions. Once this result has been measured, it must
be compared to the original setting differential as given in the
specification for the Interrupter and breaker type. In this way, as
an example, the original setting may be (10 + 1) this indicating
that the original setting was between 10 and 11 mm. Compared
to the measured value, now of say 12.8mm. This indicates that
the contact wear would be approximately 1.8 mm, which is
within tolerance of the specified 3mm permitted. From this one
could determine the remaining life expectancy of the
interrupters, as say the breaker or contactor has been in
operation for 5 years, it has worn 1.8mm. Therefore the next
inspection should be planed for (1.8 divided by 5) multiplied by
(the amount of further unknown service years) for the answer to
be less than 1.2mm (the available contact remaining).
As an equation: (1.8 / 5) x y = 1.2 (where y = the remaining life
expectancy).
4.5 Checking the vacuum
The first method is used primarily on the 3AG types. This method requires the contact pressure springs to
be disengaged, as well as the moving contact arm rod from the base of the interrupter. The vacuum is then
checked by forcing the contact lever mechanism open. There should be a firm resistance when trying to
pry open the contacts, if so, the vacuum within the bottle is still present. We recommend however, that a
safer method with types 3AH be used, which is to pressure test each individual pole with the breaker in the
open position.
Such a check should be made if there is any risk of an interrupter having developed a leak. Bus bar and
cable connections must be split. The check is performed with an HV test unit. If necessary, further
information may be obtained from the appropriate Siemens Regional Office.
27

28. 4.6 REPLACING THE VACUUM INTERRUPTERS
___________________________________________________
PLEASE NOTE : - FOR INFORMATION ONLY -
NB. - This task is only to be performed by qualified or specifically trained personnel, as the incorrect fitment of new
vacuum interrupters onto a circuit breaker can have devastating consequences to all staff, equipment, machinery and
production. There are various cautions and tests performed with this procedure, which are not listed herein.
The topics as discussed in this manual are for your information only, as they are only a brief and basic description of the
core tasks performed when replacing vacuum interrupters at the works. This is included as an informative part of the
training only. Siemens can therefore not be held liable or responsible for any loss of life, damages, or losses of what ever
nature - what so ever - should this occur as a direct result of an attempt to change interrupters using the information as
contained herein.
(For assistance with this procedure, please contact your nearest Siemens office. Or call 012 309 0128)
Example for vacuum circuit-breaker models with Vacuum Interrupters type “VS”
Removing an Interrupter
1. Isolate the circuit breaker .
2. Slacken the lateral bolt or bolts on terminal clamp 29.2.
3. Withdraw pin 48.5 from insulated coupler 48. and levers 48.6.
4. Remove the coupling pin from adapter 36.3.
5. Unscrew struts 28. from the upper pole support 20., slacken them on the lower pole support 40. and swing them
forward.
6. Undo centring ring 28.1.
7. Undo fixing screw B of the interrupter at the upper pole support 20. Push interrupter 30., together with adapter
36.3 down by about 6 mm, take out the ball cup “A” from between the interrupter and the upper pole support. Tilt
the interrupter forward and withdraw it from the lower pole support 40.
Installing an Interrupter
Note: Replacement interrupters 30. with screwed-in adapters 36.3 have been adjusted at the works. Do not alter the
adapter setting.
1. Rub and lubricate the connection surfaces. Copper sprayed connection surfaces of aluminium parts and silver
plated surfaces of copper parts may only be cleaned with a rag.
2. Insert interrupter 30. (with its evacuation nipple facing the mechanism housing) in the lower pole support 40. Slip
terminal clamp 29.2 into position.
3. Place ball cup A on the upper contact surface 31.1 of the interrupter. Screw this finger-tight to upper pole support
20. using screw B, the spring washer, the ball cup and washer, and the flat washer .
4. Firmly bolt struts 28. to pole support 20. Also tighten the bolts on the lower pole support 40.
5. Couple levers 48.6 and drive links 48.9 to adapter 36.3 using the pin supplied and lock this.
6. Push terminal clamp 29.2 and if applicable spacer tube 29.3 (only required for flat terminal clamp: see detail X on
drawing) against the looking ring or step on the movable terminal bolt 36.1 and position interrupter 30.,so that its
groove faces the connection surface of flexible strap 29.1. Tighten the bolt or bolts of terminal clamp 29.2 with a
torque of 20 Nm respectively 40 Nm, taking care to see that the copper terminal of the interrupter is not subjected
to an undue bending moment. This is achieved by tightening the bolt in the manner shown, using a torque wrench.
Use a corresponding wrench to hold the nut.
7. Tighten the interrupter fixing screw B on the upper pole support 20. , holding the interrupter firmly by its upper
Insulator and operate lever 48.6 by hand to see whether the moving contact moves freely. If need be, undo screw
B and adjust the interrupter in pole support 20. by turning and moving it slightly.
8. Tighten centring ring 28.1
28

29. 29
(Stroke excessive -Turn out eyebolt Stroke too short -Turn in eyebolt)
6. Repeat the measurement in accordance with 3 and 4.
3AF 93. .: (20 -1)
5. The stroke can be adjusted to suit by altering the setting of the eyebolt in insulated coupler 48.
3AF 35.. : (25 -1) ; 3AF 35...from year of manufacture 1990: (20 -1) ; 3AF 37../67.. : (20 -1); 3AF 92.. : 16 -1
3. Measure the distance between the lower edge of the lateral cut-out in pole support 40. and the lower edge of
terminal clamp 29.27 using vernier callipers.
4. Again link insulated coupler 48. and levers 48.6 together and repeat the above measurement. 5. The difference of
both measurements is the stroke.
Examples of Set-points:
9. Link insulated coupler 48. and lever 48.6 together by means of pin 48.5 and lock the pin in position .
10. Open and close the breaker several times off-load and then check to see that all the screwed joints are tight.
Checking the contact stroke
1. Trip the Breaker.
2. Remove pin 48.5. The interrupter contacts must now close automatically.

30. 30

31. DETAILS OF VACUUM CICUIT BREAKER ATTRIBUTES
31

32. 4.7 INSPECTION AND SERVICE OF THE OPERATING MECHANISM
GENERAL DESCRIPTION OF THE OPERATING MECHANISM
The mechanism housing (60.) accommodates all electrical and mechanical elements required for opening and
closing the vacuum circuit-breaker. The diagrams which follow show the arrangement of the individual
modules in the mechanism housing. The mechanism housing has a detachable cover 60.1
This cover (60.1) has cut-outs for the actuating
and indicating devices. The vacuum circuit-
breaker is closed by means of the push-button
(53.). The cover includes an opening (50.1) for
the hand crank. The stored-energy mechanism
state is shown by the indicator (55.1). The
indicator (59.1) shows the breaker state (ON -
OFF). The operating cycle counter (58.1)
indicates the number of “ON-OFF” charging
operations. The rating plate (51.) is attached to
the mechanism hosing but visible trough an
opening (51.1) on the cover. The different
types of circuit breakers i.e. 3AG or 3AH differ
slightly in front cover layout and appearance,
but this is due to small differences in operating
mechanism design. Yet, all the basic elements
shown here on the operating mechanism front
cover are the same for most 3AF or 3AH
types, but their positions may vary.
32
The motor (50.4) immediately recharges the closing spring (62.) .In the event of motor power supply failure,
the closing spring can be charged by means of a hand crank (50.).The movement is transmitted to the pole
assemblies via moulded-plastic operating rods (48.). ) for the hand crank, behind which the hand crank
coupling (50.5) of the gearing (50.2) is located. The stored-energy mechanism state is shown by the
indicator (55.).

33. 4.8 MECHANICAL SERVICE & INSPECTION
Remove the front cover of the breaker to expose the operating mechanism. Check each mechanical part
within the mechanism for wear or possible damage. All friction surfaces must be adequately lubricated. Also
check the status of the lubricant, by rubbing it onto 2 fingertips and moving then back and forth against one
another. The grease must feel soft and smooth and must not pull into threads when fingers are pulled apart. If
the lubricant is dry, or sticky, it must be removed from the mechanism before application of the new grease.
This may be done with the use of electrical cleaning solution and a cloth, but not on parts within direct contact
of plastic. These must be cleaned with a soap solution, and then treated with lubrication spray before
application of new grease. The type of grease to be used as a replacement in the operating mechanism as
per specification is Kluber Isoflex Topas L 32.
Check if the breaker mechanical truck interlock is operational, the breaker must not be able to close when the
racking lever is in the racked out position. Also check, that when the lever is turned to the racked in position
the limit switch at the base of the lever extension makes adequately. The damper rubber for trip shock
absorbency, at the base of the shaft, must be checked that it is loose and free to move. On the contact arms,
check that the contact finger spring tension and the condition of the spring support assembly, this may be
done with a Jig, the same thickness as that of the receiving contact copper bars. Tension on the Jig piece
must be tight, and all parts of the assembly must be clean. (Treat for Rust protection). On completion lubricate
the contact arm fingers with Klubber long term 2 plus.
Lubrication points of the operating mechanism
Key to Parts
a Crank pin for push
-button operation
b Lever bearing
c Cam contour
d ON latching
e Diverting auxiliary
switch
f Auxiliary switch
g Opening spring
guide
h Diverting auxiliary
switch
j Switch shaft bearing
k OFF latching
I Cam OFF latching
m Stop
p Opening spring
bearing
=
=
Key of Lubricant types
Lubricant order Information
33

34. 4.9 ELECTRICAL SERVICE AND INSPECTION
Check each electrical connection on the terminal rail and within the operating mechanism for tightness and
good contact. Check the existing wires for any visible insulation damage, and that they are clear from moving
mechanical parts and firmly strapped. Check all electrical components such as limit switches, mechanical
operated relays and contactors. These must be functional and easy to operate.
Should any of these be tight or damaged, then treat with electrical contact spray or replace as required. If the
breaker is fitted with a connector plug, the connector pins on both ends of the plug must be inspected. Check
for any loose connections, plug pins and burnt pin tips. Replace or amend as required.
.
SERVICE COMPLETION & PUTTING BACK INTO OPERATION
On completion of the service inspection, ensure that all parts and components of the circuit breaker have
been correctly re-assembled and that all service tools and accessories are removed. Ideally, a few
mechanical test operations (+/- 5) should be performed to ensure correct function. This will also allow newly
applied grease and lubrication to penetrate all treated components.
With removable breakers, the test operations may be done with the breaker racked into the test position,
where after, if successfully tested, the breaker may be put back into normal operation.
With fixed mounted breakers however, the test operations have to be done with the breaker in position. It is
important, in this case, to take special precautions when testing the breaker.
The bus bar connections are still earthed, and the supply side isolated. As a special precaution, remove the
earth connections from the breaker, but leave the supply side Isolated and locked out. The breaker may be
switched on and off mechanically in this condition where after, if successfully tested, the breaker may be put
back into normal operation.
In performing the test operations it is possible in both the above cases, that the breaker will trip immediately if
the mechanism is fitted with an under-voltage coil, or if the internal shunt-trip is being triggered from the
auxiliary protection circuit. In this case, an auxiliary supply will be required to hold in the under-voltage coil (at
the correct voltage as indicated on the coil), and / or the supply wire to the shunt trip coil may be temporarily
removed for test purposes.
Note: for fixed mounted breakers this must only be done if the supply side is isolated and locked
out, for removable breakers this must only be done if the breaker is in the test position. In both
cases, there must be no live switching of power during the test operations.
34

35. 5. FIRST LINE MAINTENANCE FOR VACUUM CONTACTORS
5.1 INTRODUCTION
Note: The procedures for maintaining contactors follows very closely to that of circuit breakers.
Contactors however, do not require as thorough a service inspection as with circuit breakers.
Contactors carry an interrupter-life time guarantee and are designed in such a manner that they
allow for wear and tear, without affecting adjustment. It is recommended to do a minimum of at
least 1 visual inspection per annum, just to ensure that all is still within the safe operating
parameters. Some contactors may differ with regard to their lifetime and guarantee, with the
amount of operations being subject to change pending the type of contactor ordered. This
lifetime is distinguished by the model classification with reference to the product catalogue.
The main difference between a vacuum contactor and a vacuum circuit breaker is that the
contactor utilises the electromagnetic coil effect for its operation, sometimes supported by a
spring-loaded trip mechanism which is charged during the electric closing operation, in order to
speed up breaking-operation time.
The vacuum circuit breaker on the other hand is opened and closed purely via mechanical
loaded spring force, where in most cases an electric motor is used to charge the closing coil-
spring which retains and stores its energy, until triggered by hand or solenoid. The trip spring is
charged during the very powerful closing spring operation. The spring in a high speed
mechanism can induce a force of approximately 1Ton / per cm. (fingers passop!!!!)
Construction
The HV vacuum contactor comprises three subassemblies:
1. - The HV section with the three vacuum interrupters
2. - The LV section with the solenoid-operated mechanism,
the central terminal block, the contactor relay, the economy
resistor, the auxiliary contacts and
3. - the drive lever.
High-voltage vacuum contactors
are switching devices with
solenoid-operated mechanisms
suitable for high switching
frequencies and unlimited ON
duration. The solenoid-operated
mechanism is suitable for AC or
DC duty.
The vacuum contactors are
suitable for normal switching
operations in AC circuits of any
type, e.g. three-phase motors,
transformers, capacitors and
resistive loads. They are suitable
for motor reversal duty (refer to
diagram in catalog HG11 section
4). The vacuum contactors are of
the non-enclosed type, degree of
protection IP 00 to DIN 40 050
and IEC 144. They are suitable
for use in buildings with poor
thermal insulation or low thermal
capacity, heated or cooled,
without temperature monitoring;
heating or cooling may even fail
for several days. Condensation
about once a month for 2 hours is
permissible.
35

36. Contactors - & The effects of Operational Altitude
Adjusting the vacuum contactor according to the site altitude
Adaptation work must be done before the drive is installed! Adjustments on the rear of the vacuum
contactor are necessary if the site altitude is different from that set at the works, (-200 m to +1250
m). Press in both setting plugs using a screwdriver until the setting plug can be turned. Then turn the
setting plug to the setting mark of the corresponding site equipment-situ altitude
Vacuum contactor with cable harness connected up
36

37. Triple-pole vacuum contactor 3TL61
1 Moulded-plastic h
2 Drive c
ousing
hamber
rrupter
3 Drive lever
4 Vacuum inte
5 Upper terminal
6 Lower terminal
7 Side plate
37

38. Sectional view of a high-voltage vacuum contactor in the "Off" position
(Arrows indicate the direction of travel for the "On" position)
1 Moulded-plastic housing
2 Drive chamber
3 Drive lever
3.1 Rocker
3.3 Cup
3.4 Nut
3.5 Lock nut
3.6 Armature
3.7 Support plate
3.8 Stop
3.9 Guide
4 Vacuum interrupter, complete
4.1 Vacuum interrupter
4.7 Compression spring
8. Magnet system
8.1 Solenoid
8.2 Magnet core
8.3 Magnet plate
9. Setting unit
9.1 Notch
9.2 Setting plug
9.3 Compression spring
9.4 Spring retainer
10 Auxiliary switch
11.1 Economy resistor
12 Terminal block
Mode of operation
The drive lever (3) takes the form of angle lever with point A as the fulcrum. This lever provides the mechanical connection
between the solenoid-operated mechanism and the vacuum interrupter. When the magnet is not excited, the lever is held in
the "Off" position by the compression springs (9.3). Point B of the drive lever is now in its extreme upper position. At this point,
the rocker (3.1) engages with the nut (3.4) of the vacuum interrupter via the cup (3.3) . This causes the contacts to be kept
apart in the "Off" position against the atmospheric pressure. The solenoid (8.1) is energized for closing so that the armature
(3.6) fitted to the rocker (3.1) is attracted by the magnetic system against the force of the two compression springs (9.3).
Point B of the drive lever then moves to its extreme lower position so that the nut (3.4) of the vacuum interrupter (4) is
released and the moving contact can be pressed against the fixed contact by the atmospheric pressure. The integral rocker
(3.1) presses the contact pressure springs (4.7) together and there by produces the necessary contact force. The drive
mechanism is so constructed that the nut (3.4) is not in contact with the cup (3.3) with the contactor in the "On" position. This
ensures that the "On" switching position is always reached, definitely and completely. The clearance between the cup (3.3)
and the nut (3.4) in the "On" switching position allows the solenoid drive to accelerate during opening operations.
38

39. Rating of the auxiliary contacts
Number of auxiliary contacts
4NO + 3NC/6NO + 5 NC are available
Short-circuit protection – Fuse Blow
The vacuum contactors are not designed to switch short-
circuit
currents. It is therefore absolutely essential to provide
shortcircuit
protection.
The best protection is provided by HV HRC fuses.
Overload and short-circuit protection of
hight-voltage motors
Overload protection
For protecting high-voltage motors against overload, it is
possible to use thermally delayed overload relays.
Short-circuit protection
HV HRC fuses are used for short-circuit protection in
conjunction
with 3TL6 vacuum contactors.
- The HV HRC fuse is subjected to most stress by the
starting current when an electric motor is switched on.
Under such stresses, the fuse must neither blow nor be
damaged.
- The stressing of the fuses is also affected by the starting
time and the starting frequency of the motors.
In catalog HG12 Part 2 these data have been taken into
account in the motor fuse protection table and lists the
smallest
HV HRC fuse to be connected in series on the input side.
Prior to commissioning, check the
vacuum contactor in accordance with the
following points:
1. Clean them as applicable (for details
refer to "Maintenance page 24).
2. Check all fixing and terminal screws
for tightness and test the switching action
of the vacuum contactor several times.
3. Check proper functioning of the
auxiliary switches. Test and adjust the
supplementary aquipment (thermal
overload relays, time relays).
Switch on the high-voltage supply after
all the functions have been checked,
making sure that all the safety
regulations and operational requirements
have been met.
Cleaning
To assure the insulating capacity, it is necessary that the
insulating components be clean. Insulating components
and external contactor parts must be wiped with a damp
cloth.
Use only warm water with the addition of a mild liquid
household detergent as cleaning agent.
39

40. Titel Title
Bestellort / Bestell-Nr. Place of
Order / Order No. PTD M C P1 Log
Berlin
9229 9871 174
Auswechseln der Schaltröhren
Replacing the interrupters
bis Seriennummer 31 670 935 up to serial
No. 31670 935 von Seriennummer 31 670
936 from serial No. 31670 936
9229 9876 174
Auswechseln der elektronischen SparschaltungReplacing the electronic
economizer 9229 9873 175
Auswechseln des Hilfsschalterblockes Replacing the auxiliary switchblock 9229 9874 174
Mechanische EinschaltverklinkungMechanical closing latching 9229 9875 174
Additional First Line maintenance brochures and material available:
Titel Title
Bestellort / Bestell-Nr. Place of Order /
Order No. PTD M C PB12 P1 Log Berlin
Auswechseln der Schaltröhren Replacing the interrupters
9229 9558 174
Mechanische Einschaltverklinkung Mechanical closing latching 9229 9574 174
Mechanische Einschaltsperre Mechanical closing lockout
9229 9575 174
Auswechseln des Hilfsschalterblockes
Replacing the auxiliary switchblock 9229 9592 174
Auswechseln der Magnetspulen Replacing the magnet coils
9229 9654 174
Sperrglied für mechanische Verriegelung
von 2 Vakuumschützen 9229 9655 174
Blocking element for mechanical interlock
of 2 vacuum contactors
Auswechseln von Magnetspulen und Widerständen Replacing of magnet
coils and resistors 9229 9658 174
Austausch des Gleichrichters 3TY5694-2A gegen Gleichrichterbaustein
3AX1525-1F Replacing the rectifier 3TY5694-2A with a rectifier module
3AX1525-1F
9229 9689 174
Arbeitsstromauslöser für Vakuumschütz 3TL6 Shunt release for vacuum
contactor 3TL6 9229 9725 174
40

41. 41
VACUUM CIRCUIT BREAKER TEST SHEET & CHECK LIST
SUBSTATION : INSPECTION DATE :
FEEDER NAME : INSPECTED BY :
CIRCUIT BREAKER / CONTACTOR DETAILS
C/B - CTR. TYPE NUMBER C/B - CTR. RATED
VOLTAGE
C/B - CTR. RATED
CURRENT
RATED SHORT CIRCUIT
A
RATED CONTROL
VOLTAGE
NUMBER OF OPERATIONS YEAR OF MANUFACTURE C/B -CTR. SERIAL
NUMBER
SERVICE CHECK LIST (tick applicable box)
1. SAFETY FIRST YES NO
HAVE ALL THE ROUTINE MAINTENANCE SAFETY PROCEDURES BEEN COMPLETED ?
2. CONDITION OF THE BREAKER POOR AVRGE GOOD
• GENERAL CONDITION
• CONDITION OF LUBRICATION
3. MECHANICAL SERVICE YES NO
• WAS THE BREAKER / CONTACTOR CLEANED ?
• WAS THE GREASE REPLACED IN THE OPERATING MECHANISM (WITH ISOFLEX TOPAS L32) ?
• WERE ALL MECHANICAL BEARINGS AND LEVERS INSPECTED ?
• WERE ALL BEARINGS LUBRICATED ?
• WERE ALL MECHANICAL CONNECTIONS CHECKED FOR TIGHTNESS ?
• WERE ANY MECHANICAL PARTS FOUND TO BE DAMAGED ?
• DOES THE MECHANICAL INTERLOCK ON THE BREAKER TRUCK FUNCTION CORRECTLY ?
• DOES THE LIMIT SWITCH FOR THE RACKING “IN” AND “OUT” LEVER FUNCTION CORRECTLY ?
• IS THE DAMPER RUBBER (FOR TRIP SHOCK ABSORBENCY) IN THE MECHANISM, LOOSE ?
• WAS THE SPRING TENSION OF THE CONTACT FINGERS CHECKED ON EACH CONTACT ARM ?
• ARE THE SPRINGS SUPPORTING EACH CONTACT ARM STILL IN GOOD CONDITION ?
• WERE THE CONTACT ARM FINGERS LUBRICATED (WITH LONG-TERM 2 PLUS) ?
• WAS THE CONDITION OF THE VACUUM CHECKED ON EACH INTERRUPTER ?
4. ELECTRICAL SERVICE
WERE ALL ELECTRICAL CONNECTIONS CHECKED FOR TIGHTNESS ?
WAS THE CONTACT WEAR ON EACH INTERRUPTER CHECKED (WHITE DOT INSPECTION) ?
WERE ALL WIRES CHECKED FOR INSULATION DAMAGE AND MECHANICAL CLEARANCE ?
WAS THE FUNCTION OF LIMIT SWITCHES (S21; S22; S23) IN THE MECHANISM CHECKED ?
WAS THE AUX. SWITCH (S1) CHECKED FOR FUNCTION AND SIGNS OF CONTACT BURN ?
WERE THE CLOSE AND TRIP COILS (-Y1 & -Y9) CHECKED FOR EASY MOVEMENT ?
ARE THE BRUSHES ON THE CHARGING MOTOR STILL OF AN ADEQUATE LENGTH ?
ARE THERE ANY SIGNS OF BURNING HAVING OCCURRED ON THE MOTOR COMMUTATOR ?
WAS THE HARTING PLUG CONNECTOR INSPECTED FOR LOOSE PINS AND CONNECTIONS ?
5. TEST OPERATIONS
WERE AT LEAST 5 MANUAL TEST OPERATIONS PERFORMED ?
WERE AT LEAST 2 ELECTRICAL TEST OPERATIONS PERFORMED ?
WERE ANY DEFECTS OBSERVED DURING THESE TEST OPERATIONS ?
5. ANY COMMENTS AND NOTES FOR ACTION OR FOR NEXT INSPECTION:
ARTISAN / TECHNICIAN SIGNATURE DATE