ABB UCC Series User manual

On-load tap-changers, types UCC and UCD
with motor-drive mechanism, type BUE
Installation and Commissioning Guide
1ZSE 5492-117 en, Rev. 5, 2003-03-30

This document must not be copied without our written permission, and the
contents thereof must not be imparted to a third party nor be used for any
unauthorized purpose. Contravention will be prosecuted.

Recommended Practices
ABB recommends careful cons derat on of the follow ng factors when nstall ng on-load
tap-changers:
Before you nstall or comm ss on a un t, make sure that the personnel do ng the job
have read and fully understood the Installat on and Comm ss on ng Gu de prov ded
w th the un t.
To avo d damag ng the un t, never exceed the operat ng l m ts stated n del very
documents and on rat ng plates.
Do not alter or mod fy a un t w thout f rst consult ng ABB.
Follow local and nternat onal w r ng regulat ons at all t mes.
Use only factory author zed replacement parts and procedures.
WARNING, CAUTION and NOTE
WARNIN
A WARNING provides information which, if disregarded, could cause injury or
death.
CAUTION
A CAUTION provides information which, if disregarded, could cause damage to the
equipment.
NOTE: A NOTE provides additional information to assist in carr ing out the work
described.
Safety Precautions
WARNIN
Unused transformer oil is slightly harmful. umes from unused warm oil may
irritate the respiratory organs and the eyes. After long and repeated contact with
transformer oil skin becomes very dry.
Used on-load tap-changer oil from diverter switch housings and selector switch
housings contains harmful substances. umes are irritating to the respiratory
organs and the eyes and are very easily set on fire. Used transformer oil may well
be carcinogenic.
Avoid contact with the oil as much as possible and use oiltight protective gloves
when handling the oil.
irst aid:
Skin contact: Wash the hands. Use skin cream to counteract drying.
In the eyes: Rinse the eyes in clean water.
Swallowing: Drink water or milk. Avoid vomiting. Call a doctor.
Collect used oil in oil drums.
To be continued on the next page.

Waste and cleaning up: Should be absorbed by an absorber. Treat it as hazardous
to the environment.
Upon fire: The fire should be extinguished by using powder, foam or carbon acid.
WARNIN
Be aware of the risk for slipperiness caused by oil spillage for instance when
working on the transformer cover.
WARNIN
The motor-drive mechanism must not be installed in any explosive atmosphere.
The electrical equipment creates sparks which can cause an
explosion.
WARNIN
Before any work is carried out on the on-load tap-changer:
Make sure that the transformer is disconnected and that earthing is properly
carried out. Obtain a signed certificate from the engineer in charge.
WARNIN
Before carrying out work on the on-load tap-changer, put the LOCAL/REMOTE
switch in the motor-drive mechanism to position 0. It is also recommended to shut
the door of the motor-drive mechanism and pad lock it when work is carried out
on the on-load tap-changer. The key should be kept by the operator. This is done
to avoid unexpected start of the motor-drive mechanism.
WARNIN
Before starting any work inside the motor-drive mechanism, the auxiliary power
must be switched off.
N.B. The motor, contactors and heating element may be energized from separate
sources.
During Drying of the Transformer
CAUTION
The diverter switch should not be installed during dr ing, since the process removes
grease needed for operation.
CAUTION
During dr ing with hot air and vacuum, the maximum permitted pressure difference
for the diverter switch housing is 100 kPa at the maximum permitted temperature of
135 oC (275 oF).
v

CAUTION
During dr ing b the vapour phase process the cover of the diverter switch housing
and the bottom valve should be left open. The valve is opened with the special bottom
valve ke , a long hexagonal rod. The maximum permitted temperature is 135 oC
(275 oF).
CAUTION
Use the special bottom valve ke onl (delivered with the on-load tap-changer) to
operate the bottom valve through the oil draining tube. The use of a stiffer tool ma
damage the valve.
CAUTION
Do not operate the on-load tap-changer during the dr ing process or afterwards until
it is filled with oil, to avoid seizing.
Mounting of Gaskets
CAUTION
Sealing surfaces and gaskets must be clean and undamaged. Diametricall
opposed bolts in sealing joints must be tightened alternatel several times, beginning
with a low tightening torque and finall with the recommended tightening torque as
described in section 1.8 Tightening Torque, in this guide.
During Oi Fi ing
WARNIN
When oil that has been used in a diverter switch housing is pumped out,
conducting tubes and hoses that are earthed should be used to avoid the risk of
explosion due to the gases produced by the arcs during service.
CAUTION
Do not fill oil into the diverter switch housing if the transformer tank is under vacuum
and the diverter switch housing is not.
CAUTION
Do not fill oil into the transformer tank if the diverter switch housing is under vacuum
and the transformer tank is not.
CAUTION
Leave a gas cushion on top of the oil in the diverter switch housing.
v

After Oi Fi ing
CAUTION
Do not energize the transformer earlier than three hours after oil filling in
atmospheric pressure. This waiting period is needed to allow airbubbles to disappear.
NOTE: Check the oil level one month after filling. It is usual for the oil level of the oil
conservator to fall due to gas absorption in the oil from the gas-cushion in the on-
load tap-changer, if the on-load tap-changer is not operated. Restore the gas-cushion
and the oil level according to section 6.5.
During Service
WARNIN
Small amounts of explosive gases will always come out from the breathing devices
(dehydrating breather or one-way breather). Make sure that no open fire, hot
surfaces or sparks occur in the immediate surroundings of the breathing devices.
WARNIN
If a failure in power supply occurs during operation, the operation will be
completed when the power returns.
WARNIN
The hand crank must not be inserted during electrical operation.
WARNIN
If the on-load tap-changer is not in its exact position and the hand crank is pulled
out, the motor-drive mechanism will start and go to the exact position if the power
supply is on.
CAUTION
After a pressure rela trip, follow the instructions in the chapter Pressure Rela  in
the Repair Guide.
CAUTION
The pressure rela is a calibrated monitoring instrument. It must be handled with
care and protected against careless handling or an kind of mechanical damage. Do
not open the package of the pressure rela until ou are about to install it on the on-
load tap-changer.
v

7
Contents
1 Introduction ____________________________________________ 9
1.1 Type Designation ________________________________________ 10
1.2 Required Tools __________________________________________ 13
1.3 Required Material _______________________________________ 13
1.4 Oil ___________________________________________________ 14
1. Oil Conservator _________________________________________ 14
1.6 Oil Filter Unit for Continuous Oil Filtration ___________________ 1
1.7 Weights _______________________________________________ 1
1.8 Tightening Torque _______________________________________ 17
2 Receiving ______________________________________________ 17
2.1 Unpacking _____________________________________________ 17
2.2 Inspection on Receipt _____________________________________ 17
2.3 Temporary Storage before Assembly _________________________ 17
3 Installation in the Transformer ______________________________ 18
3.1 Cover-Mounting _________________________________________ 19
3.1.1 UCCwith Tap Selector size IV _____________________________ 19
3.1.2 UCDwith Tap Selector size III _____________________________ 23
3.1.3 UCDwith Tap Selector size G _____________________________ 26
3.2 Yoke-Mounting _________________________________________ 33
3.2.1 Mounting when the Transformer Ratio Measurement
is carried out before Drying ________________________________ 34
3.2.2 Mounting when the Transformer Ratio Measurement
is carried out after Drying _________________________________ 36
3.2.3 Mounting on Transformer Cover ____________________________ 37
3.3 Connection to Terminals __________________________________ 40
3.4 Transformer Ratio Measurement ____________________________ 42
3.4.1 Transformer Ratio Measurement before Drying ________________ 43
3.4.2 Transformer Ratio Measurement after Drying __________________ 43
4 Drying ________________________________________________ 44
4.1 Observations before Processing _____________________________ 44
4.2 Observations after Processing ______________________________ 44
4.3 Installation of Diverter Switch ______________________________ 4
Final Assembly _________________________________________ 49
.1 Mounting of the Motor-Drive Mechanism _____________________ 49
.2 Mounting of External Drive Shafts __________________________ 1
.2.1 Mounting of Vertical Drive Shaft ___________________________ 3
.2.2 Mounting of Horizontal Drive Shaft _________________________
.2.3 Before Operation ________________________________________ 7
.3 Pressure Relay __________________________________________ 8
.3.1 General ________________________________________________ 8
.3.2 Installation _____________________________________________ 8
.3.3 Checking at Commissioning of the Transformer ________________ 9
.4 Assembly of Accessories __________________________________ 9
. Connection to the Oil Conservator ___________________________ 60

8
6 Oil Filling ______________________________________________ 61
6.1 Filling Methods and Restrictions ____________________________ 61
6.2 Before Filling ___________________________________________ 61
6.3 Filling at Atmospheric Pressure _____________________________ 62
6.4 Filling under Vacuum ____________________________________ 62
6.4.1 Oil Conservator Filled Afterwards ___________________________ 63
6.4.2 Oil Conservator Filled under Vacuum ________________________ 63
6. Restoring the Gas Cushion _________________________________ 64
6. .1 Procedure ______________________________________________ 6
7 Electrical Connection and Testing ___________________________ 66
7.1 General ________________________________________________ 66
7.2 Connecting and Testing the Motor-Drive Mechanism and the
On-Load Tap-Changer ____________________________________ 66
7.3 Electrical Tests on Transformer _____________________________ 67
7.4 After Energizing _________________________________________ 67
8 Transport ______________________________________________ 68
8.1 Dismantling before Transport ______________________________ 68
8.1.1 Dismantling Preparations __________________________________ 68
8.2 Oil Level During Transport ________________________________ 69
8.2.1 Transformer filled with Oil ________________________________ 69
8.2.1.1 Conservator mounted _____________________________________ 69
8.2.1.2 Conservator dismounted ___________________________________ 69
8.2.2 Transformer drained _____________________________________ 69
8.2.2.1 Conservator mounted _____________________________________ 70
8.2.2.2 Conservator dismounted ___________________________________ 70
9Commissioning _____________________________ 70
9.1 Connection to the Oil Conservator ___________________________ 72
9.2 Mounting the Motor-Drive Mechanism and Drive Shafts _________ 72
9.2.1 Mounting of the Motor-Drive Mechanism _____________________ 72
9.2.2 Disc-Brake _____________________________________________ 72
9.2.3 Mounting of the External Drive Shafts _______________________ 73
9.2.4 Mounting of the Vertical Drive Shaft ________________________ 73
9.2. Mounting of the Horizontal Drive Shaft ______________________ 7
9.2.6 Before Operation ________________________________________ 77
9.3 Pressure Relay __________________________________________ 77
9.4 Accessories ____________________________________________ 77
9. Oil Filling ______________________________________________ 77
9.6 Electrical Connection and Testing ___________________________ 78
9.6.1 Motor Protection ________________________________________ 78
9.6.2 Disc Brake _____________________________________________ 78
9.6.3 Counter _______________________________________________ 78
9.6.4 Position Transmitter and other Position Switches _______________ 79
9.6. Light __________________________________________________ 79
9.6.6 Heater _________________________________________________ 79
9.7 Putting into Operation ____________________________________ 79

1 Introduction
1 Introduction
The arrangement of on-load tap-changers types UCC and UCD are shown in
Figs. 1 and 2.
A UCC on-load tap-changer has always tap selector IV. A UCD on-load tap-
changer has tap selector III or G.
To make transportation easy the on-load tap-changer is delivered in three main parts.
These are diverter switch housing, tap selector and motor-drive mechanism.
The on-load tap-changer is performed for cover-mounting and for yoke-mounting.
Cover-mounting means that the diverter switch housing is lowered through the hole in
the transformer tank and then bolted straight onto the transformer cover, and after that
the tap selector is mounted. Yoke-mounting means that the on-load tap-changer is
temporarily put on a fork located on the active part of the transformer. Yoke mounting
allows the transformer manufacturer to connect the windings to the on-load tap-changer
before drying and without having the transformer cover mounted. The
transformer cover is then lowered onto the tank, and the on-load tap-changer is lifted
and bolted to the cover. Please use the appropriate instruction for cover-mounting or
yoke-mounting in chapter 3.
At cover-mounting the diverter switch housing is installed on the transformer cover
before joining with the tap selector.
After the drying process of the transformer the motor-drive mechanism and bevel gear
are fitted to the transformer tank and the drive shafts are fitted to complete the
assembly of motor-drive mechanism, bevel gear and on-load tap-changer before oil
filling and testing.
The arrangement of the on-load tap-changer systems is shown in Figs. 2-2b.
Position numbers in the Installation Guide, for example SA11 (see chapter )
correspond with those in the packing list for the on-load tap-changer.
All instructions are for one on-load tap-changer unit. In case of more than one unit on
the transformer, carry out the same procedures for each unit.
9

1.1 Type Designation
U C C . . XXXX/YYYY/IV
U C D . . XXXX/YYYY/III
Example: UCDRE 650/1000/III
Type of switching
L Linear
R Plus/Minus
D Coarse/Fine
Type of connection
N T ree-p ase star point (one unit)
E Single-p ase (one unit)
Impulse withstand voltage to earth
Maximum rated through-current
Tap selector size
1 Introduction
10

11
1 Introduction
Serial No.
Serial No. in the bottom
of the diverter switch
(see Fig. 29)
Diverter switch
housing
Tap selector si e III Tap selector si e GTap selector si e IV
Fig. 1.
Serial No. Serial No.
Shielding ring (not in
combination with tap
selector si e G)
Serial No.

1 Introduction
12
Fig. 2. T pe of connection, N, 1200 A
Fig. 2a. One two-phase unit and one single-phase unit with
motor-drive mechanisms for delta connection, 1200 A 1)
Motor-drive
mec anism
Bevel gear
Horizontal drive s afts
and protective tubes
Pressure relay
S ielding rings and caps,
only for UCC, UCD wit
impulse wit stand voltage
to eart exceeding 380 kV
Hand crank
(inside t e
cover)
Vertical drive
s afts and
protective tubes
Bevel gear
TC_00024
TC_00031 TC_00029
TC_00031
Fig. 2b. Three single-phase units with three motor-drive mechanism
for three-phase full insulation, 2000 A.
Rating plate
1) The two-phase unit
should be connected in a
corner of the delta where
the regulating windings
of the two windings are
located.

13
1.2 Required Too s
Required for work
according to chapter/section
nNormal set of open end wrenches (up to 24 mm) General
nNormal set of sockets (up to 24 mm) General
nNormal set of screw drivers General
nSocket handle General
nSet of pliers, including cutting pliers General
nDynamometric wrench -8 Nm General
nSliding caliper General
nAllen key sockets and 10 mm 3
nPipe Wrench 3.2
nBottom valve key (delivered with the on-load tap-changer) 3.2.1, 4 and 6.2
nLifting bar. Article No. LL 133 016-D 3.2.2
nSpecial hand crank for operating the on-load tap-changer 3.4
on the bevel gear (can be ordered from ABB,
under further requirements on the ordering data sheet.
Art. No. LL117 016-M).
nHack saw (only for installation)
nFile
nFolding ruler
nAir pump with hose, pressure gauge (02 0 kPa)
and connection with internal thread R 1/8 .3
nTool for opening of oil drum 6
nContainer, 0 litres 6
nSmall oil pump with connection to the oil valve 6
(For connection dimensioning see the dimension drawing
for the on-load tap-changer).
1.3 Required Materia
nRags for cleaning General
nSingle-phase diagram for the on-load tap-changer General
nGasket for transformer flange 3.1, 3.2.3
nInsulating paper 3.1, 3.2
nInsulating bushings 3.2
1 Introduction

14
Required for work
according to chapter/section
nWooden block as spacer 3.3
nGrease (ball bearing grease) GULF-718 EP,
Mobil-Grease 28, SHELL-Aero Shell Grease 22 or similar 3, 9.2.2
nOil, see section 1.4 6
nDimension drawing for the on-load tap-changer for 6
connection dimensions of the oil valve
nFlange for connection to the oil conservator flange 6.4
when filling under vacuum, see Fig. 4
nTwo oil valves for connection to flange with dimensions 6.4.1
according to Fig. 4 . Can be ordered from ABB
nEquipment for oil filling 6
nSealing tape 6.3
nMaintenance Guide for UCC/UCD 7.2
nCircuit diagram for the motor-drive mechanism 7.2
nOil filter (in case of common conservator for both the .
transformer and the on-load tap-changer) can be ordered
from ABB.
1.4 Oi
The oil quality should be of Class II according to IEC publication 296.
Table 1. Weight of oil in kg.
Type designation Oil weight 1)
UCC.. 380/...., UCD.. 380/.... 700
UCC.. 650/...., UCD.. 650/.... 760
UCC.. 1050/....,UCD.. 1050/.... 860
1) The oil for the conservator is not included.
WARNIN
Do not energize the transformer until oil has been filled according to chapter 6, Oil
illing, in this guide.
1.5 Oi Conservator
The on-load tap-changer has to be connected to an oil conservator. ABB recommends
to use a separate conservator for the on-load tap-changers with both oil and air side
separated from the main conservator of the transformer.
1 Introduction

15
The volume of the conservator should be such, that there is oil left in the conservator
even at the lowest oil temperature expected and such that no flooding can occur at the
highest oil temperature expected. Even transformers with more than one on-load tap-
changer unit require only one conservator.
A suitable dimension of the tube for connection to the conservator is an innerdiameter
of approximately 20 mm. The tube should be inclined at least 3 degrees to avoid gas
cushions in the tube. A valve in the connection to the conservator is recommended.
The conservator must be equipped with a breathing device that does not allow moist air
into the conservator and that allows the gas from the arcs to disappear.
The conservator should also be equipped with an oil level indicator and an alarm
contact for low oil level is recommended.
1.6 Oi Fi ter Unit for Continuous
Oi Fi tration
If the on-load tap-changer should have an oil filter unit for continuous oil filtration
from ABB, installation and commissioning instructions are found in the manual for the
oil filter unit, Oil filter unit for On-Load Tap-Changers, Manual delivered with the
oil filter unit.
1.7 Weights
Motor-drive mechanism BUE 1 weight: approximately 130 kg
Motor-drive mechanism BUE 2 weight: approximately 1 kg
The weights of the motor-drive mechanism and drive-shaft system are not included in
the weights given on next page.
1 Introduction

1 Introduction
Table 2. Weights for UCC on-load tap-changers
On-load tap-changer Approx. weight in kg
Type designation Tap-changer Required Total
without oil 1) oil
UCC.N.../.../IV 380/800, 1200 1050 700 1750
380/1600 1140 700 1840
650/800, 1200 1090 760 1850
650/1600 1180 760 1940
1050/800, 1200 1110 860 1970
1050/1600 1200 860 2060
UCC.E.../.../IV 380/3600 1040 700 1740
380/4200 1130 700 1830
650/3600 1080 760 1840
650/4200 1170 760 1930
1050/3600 1100 860 1960
1050/4200 1190 860 2050
1) The weight of the diverter switch, approximately 250 kg, is included.
Table 3. Weights for UCD on-load tap-changers
On-load tap-changer Approx. weight in kg
Type designation Tap-changer Required Total
without oil 1) oil
UCD.N.../.../III 380/1000 900 700 1600
650/1000 940 760 1700
1050/1000 960 860 1820
UCD.E.../.../III 380/1000 840 700 1540
380/1800 870 700 1570
380/2400 900 700 1600
650/1000 880 760 1640
650/1800 910 760 1670
650/2400 940 760 1700
1050/1000 900 860 1760
1050/1800 930 860 1790
1050/2400 960 860 1820
UCD.N.../.../G 380/1200 890 700 1590
650/1200 930 760 1690
1050/1200 950 860 1810
UCD.E.../.../G 380/1200 830 700 1530
380/2000 860 700 1560
380/3000, 3600 890 700 1590
650/1200 860 760 1620
650/2000 890 760 1650
650/3000, 3600 920 760 1680
1050/1200 890 860 1750
1050/2000 920 860 1780
1050/3000, 3600 950 860 1810
1) The weight of the diverter switch, approximately 250 kg, is included.
16

2 Receiving
1.8 Tightening Torque
The following tightening torques are recommended:
For metallic screw joints: M6, 10 Nm ±10 %
M8, 24. Nm ±10 %
M10, 49 Nm ±10 %
M12, 84 Nm ±10 %
M16, 20 Nm ±10 %
For non-metallic screw joints: M10, 9 Nm ±10 %
M12, 13 Nm ±10 %
M16, 22 Nm ±10 %
if not otherwise is stated in this guide.
2 Receiving
2.1 Unpacking
Check that the packages are free from transport damage. Open the covers of the trans-
port boxes, Remove the supporting block of wood. If any package is damaged a careful
investigation must be carried out.
Lift the on-load tap-changer parts in their lifting eyes according to Fig. 3.
2.2 Inspection on Receipt
1. Check that the diverter switch housing, tap selector, motor-drive mechanism
and accessories are undamaged.
2. If transport damage is found, and it is judged that correct operation of the on-load
tap-changer is not possible, a damage report should be sent to the insurance
company. It is also recommended that photographs are taken of the damaged
details. Mark the photos with ABBs reference number and the serial number of
the on-load tap-changer and send them to ABB for comments.
3. Check that the parts delivered, type designations and the serial number agrees with
the delivery documents, e.g. the packing list or ABBs order acknowledgement.
The serial numbers to be checked are those on the rating plate, on the diverter
switch housing and on the tap selector. The serial number on the parts belonging to
one on-load tap-changer unit should all be the same.
2.3 Temporary Storage before Assemb y
If the on-load tap-changer is not to be assembled immediately, once the delivery has
been approved the on-load tap-changer and the motor-drive mechanism must be kept
warm and dry indoors. Let the units be kept in their plastic enclosures and leave the
drying agent until assembly.
17

3 Installation in the Transformer
3 Installation in the Transformer
The cover-mounting method or yoke-mounting method is used.
WARNIN
The intermediate gear and the insulating shaft of the diverter switch housing
moves during operation.Keep away during operation to avoid injuries!
The diverter switch housing and the tap selector are designed to be lifted in the lifting
eyes, see Fig. 3.
WARNIN
To put down the complete on-load tap-changer to stand on the floor without any
support on the top of the on-load tap-changer means a risk for tilting with risk for
injuries to people and damage to the equipment.
Diverter switch housing Tap selector IV
TC_00190TC_00114
Tap selector III
TC_00185
Tap selector G
TC_00193
Fig. 3. How to lift.
18
Max 90o
Max 90o
Max 90o
Tap selector G
Max 90o
TC_00194
Max 90o

3 Installation in the Transformer
3.1 Cover-Mounting
(For Yoke-Mounting, see section 3.2).
The diverter switch housing and tap selector are delivered packed separately.
3.1.1 UCCwith Tap Selector size IV
1. Unpack the diverter switch housing and the tap selector. Remove the drying agents
and the yellow cushions with vapour phase inhibitor for protection against
corrosion in the tap selector and on the diverter switch housing.
2. Fit the gasket into the on-load tap-changer flange on the transformer cover, see
Fig. . (This gasket is not included in the delivery).
3. When the impulse withstand voltage to earth exceeds 380 kV, the on-load
tap-changer is provided with shielding rings. Before mounting the diverter switch
housing on the transformer cover two shielding rings must be dismantled, see
Fig. 7.
19
Nut M16 (30x)
Stud M16
Opening in the
transformer cover
UCC, UCD
diverter switch
Selector si e III,
IV and G
Gasket
Washer (30x)
Transformer
top cover
TC_00067
Fig. 4. Fig. 5.
fm_00222

20
3 Installation in the Transformer
4. Lift the diverter switch housing in the lifting eyes as shown in Fig. 3 and lower it
carefully through the opening in the transformer top cover, see Fig. 4. Place the
diverter switch housing correctly in position for mounting the outer shaft system
(see transformer drawing). The studs on the flange on the transformer cover shall
fit into the holes in the flange of the diverter switch housing.
Mount thirty washers and M16 nuts, see Fig. . Tighten the nuts.
. If the impulse withstand voltage exceeds 380 kV, mount first the upper of the two
dismantled shielding rings on the diverter switch housing and then the lower, see
Fig. 7.
6. Put the tap selector in position for joining to the diverter switch housing. Lift in
the lifting eyes as shown in Fig. 3.
7a. In case the on-load tap-changer is equipped with a tie-in resistor for mounting
under the tap selector, the tie-in resistor should be mounted after joining the tap
selector to the diverter switch housing. After mounting the tie-in resistor, the on-
load tap-changer must not be put down standing on the tie-in resistor. It must be
hanging, for instance in a traverse.
WARNIN
To put down the on-load tap-changer to stand on the floor with the tie-in resistor
mounted means a great risk for tilting the on-load tap-changer with risk for
injuries to people and damage of the equipment.
7b. In case the on-load tap-changer is equipped with a tie-in resistor switch, the
switch is mounted under the tap selector at delivery. A special support in the box
makes it standing on the tap selector bottom. If this special support is taken out of
the box, the tap selector can be standing on this during joining to the diverter
switch housing. After joining, the complete on-load tap-changer is lifted and the
special support is removed. The complete on-load tap-changer must not be put on
the special support. It must be hanging, for instance in a traverse.
WARNIN
To put down the on-load tap-changer to stand on the floor with the tie-in resistor
switch mounted means a great risk for tilting the on-load tap-changer with risk for
injuries to people and damage of the equipment.
8. Remove the transport locking and the lifting eyes with fasteners from the top
section of the tap selector, see Fig. 6.
CAUTION
Do not operate the tap selector until it is connected to the diverter switch housing.