Download Oil transformers

Oil Transform.
Company produces distribution transformers with power of 2500 kVA and voltage levels of 10, 20,
30 kV.
Transformers are produced with conservator and with hermetically sealed tank.
They can be installed on power-line poles or on the ground.
Transformers are produced to comply with standard and special requirements.
Slower process of insulation ageing and high stability of dielectric properties enable
considerably extended life of transformer and minimal maintenance costs.
technical characteristics
1 Frequency
Rated frequency is 50 Hz.
2 Rated high voltage
The rated high (primary) voltage is the voltage at which transformer is designed to
operate. The rated primary voltage determines the basic insulated level (BIL) of
transformer according to IEC 76. Transformers which are the subject of this manual
are designed to operate at power network voltages up to 36kV (38*kV).
3 Voltage regulation and selection of primary voltage level
warning
Handling with the tap changer and the voltage selector must be done when
transformer is out of voltage!
Voltage regulation is performed at higher voltage side of the transformer and
realized by means of turning the handle of the tap changer, which is placed on the
transformer cover. Selection and change of primary voltage level of dual primary
transformers is realized by means of turning the handle of the voltage selector,
which is placed on the transformer cover.
4 Ambient conditions and temperature rise
Transformers are designed for normal operation in the following ambient
conditions:
- the highest altitude for installation and operation of transformer is 1000m above
sea level,
- air ambient temperature may not exceed value given in technical characteristics
of transformer.
Under these conditions guaranteed temperature rise (maximal temperature rise of
oil and average temperature rise of windings) above the ambient temperature will
not exceed values given in technical characteristics of transformer.
If the ambient temperature exceeds value given in technical characteristics of the
transformer it will endanger the life time of the transformer even if the transformer
operate with rated load (IEC 354). In that case allowable temperature rises need to
be reduced to the some degree by means of reducing the transformer power.
5 Hermetically sealed transformers
This type of transformer’s construction guarantees that the transformer oil will not
come into contact with atmosphere. Transformers are C. After sealing,
pressurefilled with oil at the ambient temperature of 20 inside the transformer is
equal to normal atmospheric pressure.
Variation of the oil volume due to its temperature variations caused by variation of
the load during normal operation of the transformer causes either increase or
decrease of the internal pressure. According to absorbing manner of internal
pressure changes there are two design variants for these transformers:
1 – Hermetically sealed–completely filled with oil
In this variant changes of internal pressure are absorbed with flexible corrugated walls of the
transformer tank.Maximal overpressure inside the tank is 30kPa.
2 - Hermetically sealed–with air cushion
In this variant the transformer tank is designed with rigid structure and changes of internal
pressure are absorbed with air cushion placed underneath the transformer cover.
Maximal overpressure inside the tank is 50kPa.
The transformer tank cannot be deformed permanently if the transformer is loaded in
accordance with guidelines of standard IEC 354 (Loading guide for oil-immersed power
transformers).
warning
The oil level must not be below minimum mark for normal and safe transformer’s
operation.
It is necessary to keep air-tightness for this type of transformer’s construction.
As a default, these transformers are equipped with oil level indicator. In the event that oil level
falls below minimum mark on the scale of oil level indicator, the transformer must be
immediately switched off, any leaks found, sealed and poured with the oil up to necessary
level. Only when these actions are done it is allowed to start-up the transformer again.
6 Transformers with conservator
Transformers of this type are equipped with the conservator mounted on the
transformer cover. The conservator is connected with the transformer tank and its
purpose is to compensate any volume variations of the transformer oil. The
transformer oil is not into direct contact with the atmosphere.
The contact is realized through silica-gel placed inside dehydrating breather (placed
on the conservator) which absorbs all moisture from air and prevents it for entering
the transformer tank.
warning
The oil level must not be below minimum mark for normal and safe transformer’s
operation.
As a default, the conservator is equipped with oil level indicator. In the event that
oil level falls below minimum mark on the scale of oil level indicator, the
transformer must be immediately switched off, any leaks found, sealed and poured
with the oil up to necessary level. Only when these actions are done it is allowed to
start-up the transformer again.
7 Loading of transformers
Transformer should be loaded in accordance with guidelines of standard IEC 354 -
Loading guide for oil-immersed power transformers.
8 Short-circuit withstand capacity
Transformers are designed, manufactured and guaranteed to withstand without
any damage all mechanical and thermal effects of short-circuit in accorance with
requirements of standard IEC 76.
9 Withstand voltage
Transformers are designed, manufactured and guaranteed to withstand without
any damage all test voltages according to the customer requirements or according
to requirementa of standards which are stated on the rating plate and in the
routine test report of the transformer.
transformer construction and design
1 Magnetic circuit
The magnetic circuit is made of high quality, cold-rolled, grain-oriented silicon steel
with low magnetic losses.
The magnetic circuit is of the three-leg construction with circle cross-section.
Low level of no-load losses, small magnetizing current and low level of the noise
are achieved by modern cutting and composing technology as well as by optimized
tightening of steel strips.
2 Windings
Both the primary and secondary windings are made of electrolytic copper with the
use of high quality insulating materials. Windings are placed concentrically around
the magnetic circuit legs.
High voltage windings are multi-layer type, wounded with round enameled wire or
rectangular, paper insulated wire, for high power ratings.
Low voltage windings are wounded with rectangular, paper insulated wire or copper foil
insulated with diamond- dotted paper and presspan.
Electrical, thermal and dynamic stability of the transformer is achieved by windings
construction with adequate channels for oil circulation (cooling and hot-spot
temperature limit), right selection of insulation and effective tightening of windings
in axial and radial direction.
3 Tap changer
Transformer is equipped with a three phase off-load tap changer (at HV side) which
enabling voltage regulation only when transformer is de-energized. The voltage
regulation is realized by means of turning the tap changer handle to the required
position.
warning
Transformer must be de-energized while using the tap changer!
The tap changer handle is placed on the transformer cover.
Voltages and corresponding handle positions are stated on the rating plate. The tap
changer mechanism operates synchronously on all three phases of the transformer.
4 Voltage selector
Dual primary transformer is equipped with voltage selector besides tap changer.
The voltage selector enables voltage selection only when transformer is deenergized!
warning
Transformer must be de-energized while using the voltage selector!
The voltage selector handle is placed on the transformer cover.
The operating voltage selection (for instance 20kV or 10kV in case of 20/10 kV/kV
dual primary transformer) is realized by means of turning the voltage selector
handle to the required position.
5 Tank
The tank is made of high quality steel.
Hermetically sealed and completely filled transformers have tank with corrugated walls.
Transformers with conservator may have tank either with corrugated walls or with cooling
radiators.
High quality of the tank welding provides high mechanical strength and
impermeability so tank withstands, without permanent deformation, all strains
during transport and exploitation.
In accordance with type of the transformer and its installation place the following
facilities can be found on the tank:
warning
Do not use corrugated walls or radiators for lifting, displacement, installation or
securing of the transformer. It may result in damage of the tank or oil leakage!
oil drain valve or oil draining device,
oil sampling device,
hooks for pole mounting,
transformer support (with or without bidirectional wheels), with holes for pulling of the
transformer,
reinforcements for lifting and pushing
the rating plate (at LV side as a default),
earthing terminal
6 Cover
The following facilities can be found on the transformer cover:
HV and LV bushings,
the tap changer handle,
the voltage selector handle (dual primary type),
thermometer pocket (optional),
oil filling orifice (hole),
lifting lugs for lifting of transformer or its active part,
earthing terminal (optional)
and other facilities according to contract.
7 Conservator
Conservator (expansive vessel) is located horizontally over the tank and mounted
on conservator’s supports connected with the cover. Conservator is designed in
such a way to accept all oil volume variations during temperature change between
-25°C and 100°C.
8 Transformer oil
Transformers are filled with mineral insulating oil. Filling of the transformer with oil
must be done only after vacuuming if the transformer active part. Characteristics of
the transformers oil are in compliance with requirements of standard IEC 296 and
value of the oil breakdown voltage is above 50kV/2.5mm.
9 Anti-corrosive protection
Variant 1 – Protection with organic coats
In this case anti-corrosive protection consists of 4 coats (two primer coats and two
final color coats) with total thickness between 100 and 120 μ m. Final coat color is
dark gray (RAL 7033) as a default. Anti-corrosive protection system may be
particularly adjusted to the requirements of any contract for instance: kind of the
organic coat binder (alkyd, modificated alkyd, epoxy or polyurethane resin),
thickness and color of the final coat.
Varijant 2 – Hot-dip galvanizing
This kind of anti-corrosive protection is effective and more economic (for neutral
environmental conditions) than protection with organic coats. It is realized by hotdip galvanizing technology. Hot-dip galvanizing outlasts protection with organic
coats. Quality of zinc film is in compliance with requirements of ISO 1461 standard.
transformer accessories and equipment
1 Thermometer pocket
Transformers are equipped with a thermometer pocket enabling installation of
mercury or double contact thermometer.
Before the installation of these devices thermometer pocket must be half-filled with
the transformer oil.
Unused thermometer pocket must be sealed to prevent water or air entering into
the transformer. Water entering inside the pocket and ice expanding at very low
ambient temperatures may result in pocket damage.
2 Double contact thermometer
2.1. Double contact thermometer - AKM 44612 type
This instrument is designed for indication of the oil temperature inside transformer.
It is fitted with two electric switches (contacts for alarm and tripping) and the
indicating pointer of maximal temperature. The instrument is made for outdoor use
under tropical as well as arctic conditions.
Technical data:
note
Adjusted temperature for generation of tripping signal must not be above 105°C!


case – protective class IP43
two micro switches rated for 5A, 250V AC or 0.2A,250V DC – normally open
(NO)

electrically separated switching circuits

connection by swivel fitting BSP1” or BSP ¾”

ambient temperature: min -40°C; max +70°C

measurement range between 10 and 120°C

measurement accuracy: ±2°C between 50-120°C.
2.2. Double contact thermometer - KTT001 type
This instrument is designed for measuring of the oil temperature inside transformer
with generation of alarm and tripping signals possibility. It is fitted with magnetic
type switch. Contacts are normally open (NO).
Technical data:
note
Adjusted temperature for generation of tripping signal must not be above 105°C!

case – protective class IP43

power: 200W,2A

working voltage: 220V, 50Hz

breakdown voltage 2000V

measurement range between 20°C and 120°C

ambient temperature: min -30°C; max +60°C

accuraccy class: 4,6

connection by swiwel fitting BSP1” or BSP ¾”
3 Oil level indicator
3.1. Magnetic oil level indicator - KSS F
This instrument is mounted on transformers with conservator with purpose of
showing current oil level into the transformer. The radial movement of the float is
transmitted magnetically to the pointer.
3.2. Oil level indicator vertical – KSS-D
This instrument is mounted on hermetically sealed transformers with purpose of
showing current oil level into the transformer.
3.3. Oil level indicator vertical – Maier G1 1/2”
This instrument is mounted on hermetically sealed transformers with purpose of
showing current oil level into the transformer.
The instrument is to be screwed into the filling pipe on the transformer cover. It
offers possibility to monitor: - gas forming in the transformer, - accumulations of
air pockets in the tank, - indication of leakage.
Installation and adjustment
The oil level indicator has to be screwed to the filling pipe. The indicator device
must be adjusted in the following manner:
- unscrew the ring nut (pos.2),
- remove the viewing dome (pos.3) and sealing ring (pos.4),
- lift out the indicator scale complete with the upper magnet (pos.6),
- turn scale into the correct position by loosening the centre screw,
- again complete the instrument.
When the transformer is properly filled with oil only the white indicator should be
visible in the indicating field. Red warning field appears when oil falls below
necessary level for normal operation of the transformer.
4 Buchholz relay
Buchholz relay is a protective instrument for oil-immersed transformers with
conservator. It is placed directly into the pipe connecting the transformer tank and
conservator. This instrument is designed for detecting of faults inside the
transformer tank by monitoring of the oil level fluctuation.
faults
The buchholz relay detects following faults:
Low oil level
When the oil level in the Buchholz relay is low the upper contact closes by reacting of corresponding float
gauge and activates signalization.
In a case of serious faults gases appear in the transformer tank followed with intensive oil flow to
conservator through the Buchholz relay. At that time the lower float closes the lower contact and
transformer will be turned off. In that case contact sales department of Trafo a.d. or your supplier
immediately.
Buchholz relay operates when gases appear, loss of oil or flow rate increases what
may happen in the following cases: - electrical breakdown between live parts, electrical breakdown between live parts and magnetic circuit or the tank, - shortcircuit between turns, - interruption of phase conductor, - oil leakage from the
transformer tank, - entrance of air into the system.
The upper contact (signalization)
Closes by reacting of corresponding float gauge when gas appears in the relay or
when the oil level changes in the upper part.
The lower contact (turn-off)
Closes by reacting of corresponding float gauge when the oil level falls to the
bottom of the relay or when the oil flow speed is between 65 and 150cm3/s.
The buchholz relay must be installed with the arrow pointing to the conservator!
5 Safety valve
Safety valve is used as one of the protective devices for hermetically sealed
transformers.
Safety valve reaction enables releasing of oil from the transformer tank and
thereby overpressure caused by various internal faults can be instantaneously
relieved. This will prevent permanent deformation or even explosion of the
transformer tank.
Safety valve’s overpressure of reacting can be adjusted and its adjustment range is
between 0.03MPa and 0.040Mpa.
6 Dehydrating breather
Transformers with conservator are equipped with the dehydrating breather. The
dehydrating breather collects all moisture from air and prevents it for entering the
transformer tank. It contains silica-gel (SiO2 crystals) which absorbs the air
moisture and changes its color during air convection.
When silica-gel changes its color in the 2/3 of its volume it must be dried (drying
temperature120°C to150°C) or it must be replaced.
Oil valve of the dehydrating breather must be filled with the oil.
Transport
Displacement of the transformer can be done in the following manners:
Lifting – by means of chains or the lifting beam
Transformer can be lifted by means of the lifting lugs placed on the transformer
cover (2 or 4 psc.)
Pulling – by means of the pulling eyes
Default construction of the transformer support has the pulling eyes (with holes
diameter 12.5mm or 15mm) designed especially for this purpose. Pulling is
possible into two directions:

along longitudinal axis or

along transversal axis of the transformer.
Displacement by the forklift
Displacement by the forklift is possible when forks of the forklift are leaned on the
reinforcements of the transformer support.
note
Do not use corrugated walls, radiators, accessories or equipment, which is not
especially designed for displacement, lifting, installation or securing of the
transformer during transport! It may result in damage of the transformer tank or
oil leakage!
Sometimes hard conditions of the transportation caused by multiple reloading or
low quality of the road can result in the considerable damage of the transformer. It
may cause disturbance during transformer's normal operation or even totally
disable operation of the transformer.
Acting according to the following remarks will avoid specified problems:



Handle carefully with the transformer during the transport.
Do not use corrugated walls or radiator coolers for displacement of the
transformer.
Secure the transformer firmly during the transport to avoid its displacement.

Protect conservator, bushings and radiator coolers from punches, cracking,
breaking and damaging.

Only professional and experienced person may manage the unloading of
transformers.

Visual inspection must be done before the unloading of the transformer to
determine any possible damage. After determining of any damage, provide evidence
and immediately inform carrier and deliverer.
During transportation transformers are usually secured to the floor of the truck
trailer by means of wooden girders. Before lifting of the transformer from the
trailer it is necessary to remove wooden girders.
Weels
Placing and removing of the weels
Place solid wooden beams a little higher than wheels underneath the transformer, positioned
transversly to the transformer support.
Put transformer on the beams and fix every wheel with corresponding screws.
Lift the transformer, remove beams and carefully lean the transformer to its wheels.
Removing of the wheels has to be done in reverse order of actions.
Transformers can be also transported in wooden boxes designed and constructed
according to regulations for the overseas transport. Transformer is fixed to the
floor of the wooden box with screws, wheels are already disassembled and als fixed
to the floor next to the transformer. Packing list with the routine test report and
installation manual are packed inside the wooden box together with the
transformer. Manipulation with the wooden box must be done according to signs
placed on the box.
Acceptance and survey
Upon receipt of the transformer it is necessary to assure that transformer matches
with requirements from your order.
note
Compare technical characteristics of the transformer from your order with data
stated on the rating plate (rated power, rated voltages, vector group, etc.).
Distribution transformers are delivered to the customer fully assembled, completely
filled with insulated oil with corresponding equipment and ready for the operation.
Visual inspection is recommended to determine
any possible transport damages (broken or cracked bushings, dented wall of the tank,
damaged accessories or equipment, etc.)
and to compare ordered and delivered equipment.
Very important is to assure that manufacturer’s securing seals are not
damaged otherwise transformer’s guarantee is no more valid.
Transformer installation
At place of the installation, transformer’s weight must be distributed evenly across
all supporting points and all indicators should be visible and easily accessible.
Transformers can be installed:
1. indoor
2. outdoor (two ways):

ground installation–on the flat and solid surface

on the pole–using hooks or on the platform
Ventilation system
When transformer is going to be installed inside an electric room (the indoor
installation), particular attention should be paid to the ventilation in the installation
room (necessary for the cooling of the transformer) i.e. leading away of the heat
generated because of the total losses during the transformer operation.
We are recommending the following variants for the ventilation system of the
transformer installation room:
System without fan
Effective ventilation system consist of two openings, one is for the input of air at
ground level with cross-section area S(m2) and the other opening for the output of
air at height H (m) above the input opening, with its cross-section area S’(m2).
Necessary surfaces of the openings would be calculated as follows:
S(m²)=0.18*P(kW)/√H(m) i
S'(m²)=1.10*S(m²)
Where P(kW) is sum of no-load losses, load losses and losses of other electrical equipment
sharing the installation room.
This formula is valid for the yearly average ambient temperature of 20°C, maximal
altitude above sea level of 1000m and for maximal difference between the
openings air temperatures of 15°C.
It is also necessary that transformer must be placed at least 200mm from any solid
barrier otherwise available transformer’s power will be lower than rated because of
deteriorated cooling conditions and difficult air circulation around transformer.
System with fan
In the case of narrow and poorly ventilated rooms as well as when air temperature
inside room is much above the outside air temperature it is necessary to embed
ventilator into the output opening.
The ventilator flow (m3/s) in this case should be 0.10*P, where P (kW) is the value
of the total losses of the transformer and other electrical equipment sharing the
installation room.
connecting and preparing
Before the transformer start-up it is necessary to:

Secure the transformer to prevent any displacement.

Connecting the earthing cables.

At transformers with conservator check the value of breakdown voltage for a
sample of the transformer oil taken from the transformer tank using a sampling
valve.
Measured value must not be less than 45kV/2.5mm.

Take measurement of insulation level.
Measured value must (with 2500V, DC) must not be less than:
- 250MΩ for voltage levels >1.1kV and
- 50MΩ for voltage levels <1.1kV

Measure effective HV and LV resistances for each position of the tap changer.
These values should be equal (with reasonable tolerances) in all three phases.

Put the voltage selector handle into desirable position (dual primary
transformers – 20/10 for instance – look in 1)

Put the tap changer handle into desirable position (look in 2)

Connect HV cables to correspond HV bushings.

Connect LV cables to correspond LV bushings.

Measure earthing resistance.

Connect leads to the all applicable additional accessories and instruments
(Remark: According to the connecting diagram!)

Inspect the whole transformer to double check for any errors in the connections
or faulty equipment.

Measure insulation level of the transformer with all connections except
connection to star point.
1 Selection of the primary voltage level
(dual primary transformers)
note
Transformer must be de-energized while changing the voltage selector handle
position!
Selection of the primary voltage level (dual primary transformers)
Selection of the primary voltage level must be done when transformer is deenergized and it is realized by means of turning the voltage selector handle to the
required position. Procedure is similar to the using the tap changer handle (look in
2)
2 Voltage regulation using the tap changer
note
Transformer must be de-energized while changing the tap changer handle position!
U postupku promene položaja regulatora napona potrebno je uraditi sledeće: disconnect all cables leading to HV and LV bushings, - earth both HV and LV
windings, - put the tap changer into required position by turning the tap changer
handle, placed on the transformer cover, - re-connect all cables, - start-up the
transformer.
Variant 1 ::
Selection of the tap changer position should be done according to values of high
voltage (stated on the rating plate) in the following manner:
unblock the latch of the tap changer handle (pos.2),
push the latch until it come out of the notch,
turn the tap changer handle (pos.1) to required position,
loosen the latch and spring (pos.3) will return it to the notch of required position,
block the latch of the tap changer handle.
Position marks (numbers) on the tap changer handle correspond to the available
values of primary voltage. Connection between marks and the values of the voltage
is stated on the transformer rating plate.
Variant 2 :: Tap changer - KDR type
In this variant, selection of the tap changer position should be done according to
values of high voltage (stated on the rating plate) in the following manner:
loosen the position fixing button (red color) of the tap changer handle,
the latch is coming out from limiter by pulling up the tap changer handle and enabling turning
of the tap changer handle to required position,
push down the tap changer handle and fix it with the position fixing button.
Position marks (numbers) on the tap changer handle correspond to the available
values of primary voltage. Connection between marks and the values of the voltage
is stated on the transformer rating plate. transformatora.
Transformer operation
1 Transformer operation
During normal transformer operation it should be treated according to the internal
manuals of user.
2 Overloading
In the case of need for overloading, act according to guidelines of standard IEC
354: Loading guide for oil-immersed power transformers.
3 Damages during transformer operation
1 Overheating
Causes of the overheating can be:

continuous overloading,

unproper cooling of the transformer (insufficient air flow around transformer,
inappropriate ventilation of the installation room, etc.)

serious internal damages (in this case contact sales department of Minel Trafo
a.d.)
2 Low oil level
Caused by:

oil leakage – oil spots and traces are clearly visible underneath the transformer.
3 Apperance of gases inside the transformer tank
Apperance of gases inside the transformer tank is caused by:

partial discharges,

poorly sealing – underpressure.
4 Too high overpressure inside the transformer tank
Caused by:

overheating,

apperance of gases inside the transformer tank.
4 Routine transformer inspections
During the routine transformer inspections particular attention should be paid to:
current oil level inside the transformer (shown by oil level indicator),
temperature of the transformer oil indicated by the thermometer installed on the transformer
cover,
current value of load (Does it exceed rated power? Is the load symmetrical?),
conditions of accessories and equipment,
conditions of bushings and connections,
conditions of protective devices and their connections,
any abnormalities in the sound generated by the transformer,
any spots and traces of oil underneath the transformer.
untanking the transformer
Untanking the transformer
note
If any irregularities are discovered during the inspection, it may become necessary
to untank the transformer to determine the cause.
If there is any suspicion that gases accumulated in the transformer tank,
underneath the cover do not carry out any electrical measurements. This may
result in a spark and cause an explosion of accumulated gases. Measurements
should be only carried out when the active part is removed from the transformer
tank!
When untanking the transformer the following sequence must be done:
disconnect all cables leading to HV and LV bushings,
drain necessary oil quantity from the tank through the drain valve placed near the bottom of
the tank - disconnect all cables leading to additional accessories, equipment and protective, unscrew nuts and bolts on the cover,
lift the transformer active part from the tank by lugs on the cover,
allow some time for percolation of the active part and then place the active part on the flat, dry
and clean surface. Drained oil should be stored in a clean, tightly closed vessel. The active part
of transformer must be re-immersed in oil within 8 hours. In a case of exceeding this period
the active part must be dried again. After draying the active part should be impregnated with
oil. Now the transformer start-up should be done according to instructions for connecting the
transformer and preparing for start-up.
transformer oil
1 Collecting oil samples for testing
Transformer oil testing should be done:
before the transformer start-up,
during the routine transformer inspections,
in any circumstances indicating possibility of damage of the transformer particularly when any
protective device are triggered.
To collect a sample use a sampling valve located near the bottom of the tank. It is
important to place the collected oil sample to a clean vessel.
Transformer oil is a hygroscopic substance and must be protected against
contact with moisture.
2 Pouring of the transformer oil
In a case of need, pouring of the transformer oil should be done, through oil filling
hole placed on the cover, with new, filtered oil with the breakdown voltage value of
50kV/2.5mm and characteristics in accordance with standard IEC 296.
Pouring of oil from the same manufacturer and the same type as the oil already
inside the tank is the most preferable otherwise it is allowed to pour oil of the other
manufacturers and types but in maximal quantity of 10% from oil weight stated on
the transformer rating plate.
new in technology
The most modern equipment for steplep cutting and
packing of magnetic sheets, produced by GEORG (Germany),
enable manufacturing of transformers with very low level of losses.
Computer aidded design and construction of transformers, with moderntechnology,
which we are using in their manufacturing, enable us to produce wide range of
standard and non-standard transformers.
New in control
1 Impulse generator
Type: SGS 300 kV, 15 kJ
- impulse generator control
Type: GC223
- high resolution impulse analysin system
Type: HiAS 743
- impulse calibrator
Type: RIC 422
- overshoot compensation
Type: SGC - OC
Manufacturer: HAEFELY - TRENCH
2 Reccurent surge generator
Type: RSG 481
Manufacturer: HAEFELY - TRENCH
3 Device for measuring of tan(delta), C, cos(fi)
Type: 2818/5283
- automatic 12 kV insulation test system (tan(delta), C, cos(fi)) in-site measurements
Manufacturer: TETTEX INSTRUMENTS
4 Sound level meter
Type: 2236
- precision integrating sound level meter
Manufacturer: BRÜEL & KJAR
5 LCR meter
Type: HP 4263B
Manufacturer: HEWLETT PACKARD
Guarantee
This product is guaranteed by Trafo for a period specified in contract and
in the product guarantee list. The guarantee covers defects due to faulty
workmanship, materials and equipment.
The guarantee applies provided the product is handled properly for its internal use,
in accordance with its operation instruction and upon presentation of required
documents.
Trafo may not apply guarantee if ::

documents have been altered or changed in any way or made illegible,

type or product serial number altered, changed, deleted, removed or made
illegible,

repairs or product modifications and alternations have been executed by
unauthorised services, service organisations or persons,

damage is caused by accidents including but not limited to lightning, water or
fire, misuse or neglect, etc.