Hammond Power Solutions Indoor/Outdoor Encapsulated Three-Phase Transformers Installation Guide
INSTALLATION, OPERATION AND MAINTENANCE GUIDE
FOR INDOOR/OUTDOOR ENCAPSULATED
FOR INDOOR/OUTDOOR ENCAPSULATED
THREE-PHASE TRANSFORMERS
THREE-PHASE TRANSFORMERS
Indoor/Outdoor Encapsulated
Three-Phase Transformers
*Note: This guide is Trilingual
(English, French, Spanish)*
Up To 150 kVA
Literature No.: IOMGE3PH
Issue Date: January 2010
Safety Precautions
(1) Do not lift or move a transformer without proper equipment and
experienced personnel.
(2) Do not install the transformer until a full inspection has been
completed.
(3) Use terminals only for electrical connections, and exible connectors
are recommended.
(4) Connections should only be in accordance with the nameplate diagram
or connection drawings.
(5) Make sure all power is disconnected before attempting any work on a
transformer.
(6) Make certain all ground connections are complete and tightened before
energizing the transformer.
(7) Do not attempt to change any taps - primary or secondary, while the
transformer is energized.
(8) Do not change connections when a transformer is under excitation.
(9) Do not adjust or remove any accessories or cover plates while the
transformer is energized.
Class 1, Division 2, Hazardous Location
Installation Requirements
If this unit is designed for use in Class 1, Division 2, Groups A, B, C & D
hazardous locations then also refer to notes below:
(1) Power, input and output (I/O) wiring must be in accordance with Class 1,
Division 2 wiring methods as per Article 501-10 (b) of the National
Electrical Code.
(2) WARNING - EXPLOSION HAZARD - DO NOT DISCONNECT EQUIPMENT
UNLESS POWER HAS BEEN SWITCHED OFF OR THE AREA IS KNOWN
TO BE NON-HAZARDOUS.
CONTENTS
General Information 3
Handling 3
Receiving & Inspection 3
Storage 3
Installation 3
Ventilation 4
Accessibility 4
Sound Levels 4
Cable Connections 4
Grounding 4
Inspection Before Energization 5
Operation 5
Maintenance 5
Diagrams 1 and 2 6
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INSTALLATION, OPERATION AND MAINTENANCE
OF THREE-PHASE ENCAPSULATED TRANSFORMERS
GENERAL
Three phase encapsulated transformers are
manufactured to provide optimum performance for a
lifetime of uninterrupted service. Careful attention to
the following instructions is recommended for safe and
reliable operation.
Insta ll a t i o n , op e r a t i o n an d ma i n t e n a n c e of
transformers should be performed by qualied persons,
familiar with electrical apparatus and the potential
hazards involved.
Warning: Danger! There is the potential of electric
shock whenever working in or around electrical
equipment such as transformers. Power must
be shut off before any work is conducted on a
transformer.
As with any electrical device, transformers must be
installed according to the requirements of the national,
and local electrical codes. Refer to ANSI/IEEE C57-94
may also be referred to for recommended installation,
application, operation and maintenance of dry type
transformers.
HANDLING
Transformers are either shipped in cartons or
palletized. The units on pallets can either be lifted via a
forklift truck or hoisted by the lifting lugs provided.
Appropriate lifting equipment should be used
relative to the size of each transformer. No attempt should
be made to lift or move a transformer from any points on
the unit other than those indicated.
Please Note: On units bolted to the pallets, please
remove all the shipping bolts located at the mounting
holes.
RECEIVING INSPECTION
Immediately after receiving the transformer, it
should be inspected for any transit damage and for
correctness against the shipping documents.
The unit should be examined for any breaks in its
packaging, dented or damaged enclosures or missing
parts from the packing list.
If any damage is noted, a claim should be led
immediately with the carrier and a second copy of
all pertinent information relative to the order and the
circumstances should be led with the local sales fce.
STORAGE
Transformers that will not be immediately installed
an d energi zed, sho uld be s tored in a clean dry
environment away from any environmental airborne
contaminants.
It is recommended that transformers be stored in
a heated building, in the original packaging.
INSTALLATION
All encapsulated transformers are supplied with a
NEMA 3R enclosure. NEMA 3R units may be installed
indoors, or outdoors where applicable.
For any outdoor location, the appropriate
applicable codes must be followed including cable
installation and hardware suitable for outdoor service.
Water tight couplings must be used at the knockouts.
Encapsulated transformers must be located in
an upright position on walls, posts, beams or other
locations capable of supporting their weight.
If the application of the encapsulated units stored
or installed outdoors, will require a NEMA 4 or 12 rating
you must install an optional gasket kit which will ensure
the unit meets a NEMA 4 or 12 rating as to prevent the
ingress of moisture.
Mounting Instructions (refer to Diagram 1)
1. Select an installation location that is on a non combustible surface.
2. The mounting location must allow for air circulation
around the transformer for cooling purposes.
Please refer to the minimum distances stated in
the ventilation section.
3. Using the appropriate mounting template provided,
drill the top two mounting holes on the mounting
surface.
4. Lift the transformer into position and install the top
two mounting bolts.
5. With the transformer hanging on the top two
mounting bolts, level the unit, then with the wiring
compartment cover open, mark and drill the lower
mounting hole(s) into the mounting surface.
6. To provide NEMA 3R protection (protection from
falling rain), the transformer must be mounted
vertically with the mounting tabs facing up. For
NEMA 4 or 12 rating install the appropriate
optional gasket kit.
7. Install the lower mounting bolt, lock washer, at
washer and rubber washer into the lower mounting
hole(s) (refer to Diagram 2).
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VENTILATION
CABLE CONNECTIONS
Encapsulated transformers are required to be
installed in an area where they can be cooled by means
of the free circulation of air where the average ambient
temperature is 30°C (86°F) and should not exceed 40°C
(104°F) at any time.
Adequate ventilation is essential for transformers
to meet their nameplate kVA capability. Multiple
encapsulated transformers should be located at least
2 inches apart on units up to 10kVA and at least 4
inches apart on units over 10kVA, away from any other
obstructions to allow free, clean circulation of air.
ACCESSIBILITY
NEC standards require that transformers be
accessible for inspection and located accordingly.
However, transformers should not be located in areas
where stored items are likely to interfere with either
natural air convection or the capability to have them
inspected. Passage ways or other areas where people
could be exposed to live parts during inspection should
also be avoided.
Adequate protection should be provided under any
circumstances.
1. Open the wiring compartment by removing the
four cover hex head cap screws and washers.
2. Terminals should be cleaned and electrical joint
compounds are recommended for use on all
electrical connections.
3. Make the appropriate electrical connection to suit
the desired voltages as per the connection dia gram on the nameplate. This includes the input
connections, output connections and the ground.
WARNING: If this unit is designed for and to be
used in Class 1, Division 2, Groups A, B, C and D
hazardous locations than the power, input and output
(1/0) wiring must be in accordance with Class 1,
Division 2 wiring methods as per Articles 501-10 (b)
of the National Electrical Code.
4. Make certain to insulate any unused wire leads
with marrette connectors and electrical tape.
5. Close the wiring compartment and ensure that the
cover screw is tightly secured.
TRANSFORMER SOUND LEVELS
Transformers are an electrically energized
apparatus and by their nature emit sound due to their
component materials.
Transformers are required to meet NEMA
standards for the maximum sound levels permissible.
These sound level standards vary from 40 to 60 dB and
hence, can be an annoyance if located in close proximity
to where people work or reside.
Care should therefore be exercised in selecting
sites for transformers particularly to avoid sensitive
areas like hospitals, classrooms, medical or ofce
facilities.
The following guide lines may be helpful;
Units should be mounted away from corners or
reecting walls or ceilings.
Cable or other exible conduit should be
considered to make connections.
Acoustically absorbing materials could be
considered for walls and ceilings around the unit.
The location of the unit should be located as far
as practical from areas where sound levels could
be considered undesirable.
The connecting cable size is determined from
the line current rating of the transformers primary and
secondary windings. Convenient pre-punched knockouts
are provided on all transformer enclosures to facilitate
cable entry. (NOTE: Once a knockout is removed,
encapsulated transformers CANNOT be returned, so
ensure the correct unit is to be installed.)
GROUNDING
All core and coil assemblies are solidly grounded
to the enclosure internally to ensure that all conductive
metal parts have the same potential.
The transformer enclosure in turn should also be
securely and effectively grounded as a safety precaution.
This grounding should be in accordance with national
electrical code standards.
INSPECTION BEFORE ENERGIZATION
For the safe and proper operation of the transformer,
we recommend that the following items be checked for
completeness:
a) The insulation resistance, enclosure to primary,
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enclosure to secondary and primary to secondary,
should be greater than 10k ohms.
b) Before energizing and connecting any loads,
please measure and verify the output voltage
matches nameplate specications.
c) Ensure correct phase connections. Refer to the
nameplate vector diagram.
d) The load on a delta secondary with a 120V center
tap should not exceed the normal current rating of
the winding. This center tap is designed for a
maximum of 5% of the nameplate kVA.
e) When windings are connected in parallel (as in
the case of dual voltage primaries), the primary
taps for all coils must be connected to the identical
percentage tap positions to avoid the shorting of
turns. For tap positions, refer to the transformer
nameplate.
f) The enclosure should be grounded with the
appropriately sized conductor.
g) The total load among all the phases should be
balanced as much as possible for optimum
performance of the transformers windings. Any
3 phase or single phase load may be connected
to the transformer but the kVA loading on each
phase must not exceed 1/3 of the nameplate kVA.
h) The clearance and tightness of all electrical
connections should be checked.
i) For single phase 3-wire 240/120 volt loads, care
must be taken to ensure the neutral current does
not exceed 1/2 of the transformers kVA rating.
OPERATION
For all relatively normal and clean installations,
encapsulated transformers will operate satisfactorily
under normal conditions of energization and load.
For your reference, fully loaded transformers may
be very warm to the touch, particularly on the top of the
unit. Standards permit the temperatures of the enclosure
to be 65°C over ambient. This represents normal
loading and should not be of concern.
Encapsulated transformers are designed to operate
continuously at their full nameplate kVA rating.
If the transformer is experiencing increased
temperatures, the following load characteristics
should be considered immediately:
Rigorous motor starting loads or other impact
type loading for which a specic transformer for
that application is required.
Over-excitation of unit due to excess supply line
voltage or current.
Ambient temperatures above standard.
Overload beyond ANSI C57.96 guidelines.
Harmonic distortions of the supply line voltage
and currents.
MAINTENANCE
Un de r n o r ma l o p e r a ti n g c o nd it i o n s an d
environments, encapsulated transformers do not require
maintenance. However, periodic care and inspection
is a good practice, particularly if the unit is exposed to
extreme environmental conditions.
Peripheral inspection and external dust and dirt
removal may be carried out while the transformer is in
operation. However, access covers must not be opened
under energized conditions.
The accumulation of ice or snow will not adversely
effect the operation of encapsulated
transformers. However, the accumulation of dust or dirt
will effect the cooling of the transformer and may become
a potential fire hazard.
Internal maintenance must be performed with a
transformer de-energized, isolated and with the
terminals grounded.
The ground connection should be checked to
ensure a low impedance connection.
ANSI C57.96 provides guidance for loading
transformers under different conditions including:
Ambient temperatures that are varied from the
ambient temperatures required for transformer
operation.
Short time overload as it relates to time and
temperature and the corresponding loss of life of
the transformer.
Overload that results in a reduction of life
expectancy of the transformer.
WARNING: If this unit is designed for and to be used
in Class 1, Division 2, Groups A, B, C, and D hazardous
locations; DO NOT DISCONNECT EQUIPMENT
UNLESS POWER HAS BEEN SITCHED OFF OR THE
AREA IS KNOWN TO BE NON-HAZARDOUS
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FRONT VIEW REAR VIEWSIDE VIEW
Lifting provision on NQT4, NQT5 and NQT6 only.
BACK
Upper
mounting
holes
Lower
mounting
hole
Remove NQT enclosure cover to access the wiring
compartment or to install optional NEMA 4/12 gasket.
Side knockout
Rear knockout
NQT wiring compartment
cover NEMA 4/12 gasket
Side
knockout
NQT wiring compartment
cover mounting hardward
NQT wiring
compartment cover
Encapsulated transformer
in NQT enclosure
NEMA 4/12 gasket shown installed
on inside of NQT enclosure wiring
compartment cover. Ensure gasket
holes are aligned with cover holes
NQT enclosure
mounting holes
DIAGRAM 1: Typical NQT Series Enclosure Mounting for Three Phase Encapsulated
Transformers. (For NQT2, NQT3, NQT4, NQT5 & NQT6 only)
DIAGRAM 2: Typical NQT Enclosure Gasket Kit Installation Diagram to convert to a
NEMA 4 or 12 Rating.
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