Document 2.4.126, Revision 4
October 2017
9
Three-Phase Padmounted Distribution Transformers
Lifting and Handling
Lifting hooks are provided near the top of the
transformer tank for lifting. All four lifting hooks
must be used simultaneously. The transformer
must not be lifted from any points other than the
provided lifting hooks. Do not use holes in the
lifting hooks for lifting. These holes are for tie-down
purposes only and are not suitable for lifting.
Transformers should be lifted in an upright position,
allowing the transformer to tilt no more than 15
degrees from vertical. Lifting cables should be no
more than 20° from vertical. It is recommended
that a spreader bar be used to keep the lifting
cables nearly vertical to enable a safe lift and
to reduce the likelihood of tank deformation or
damage to painted surfaces.
Lifting the transformer with a forklift is not
recommended, since weight and balance can be
problematic and radiator panels can be easily
damaged. Refer to the transformer nameplate
to determine the total weight of the assembled
transformer. Special care must be taken when
handling transformers when the ambient
temperature is below minus 20°C (minus 4°F);
otherwise, permanent damage to the transformer
may result.
Jacking, Skidding, and Rolling
The transformer tank base is designed for jacking,
skidding and rolling. Do not use radiator fins,
bushings, valves, pipe fittings, gauges or sheet
metal surfaces for jacking. Jacking must be done
using the proper jacking provisions from two
adjacent corners simultaneously to prevent warping
of the tank bottom. When rolling, use an adequate
number of rollers to distribute the transformer
weight evenly. Refer to the transformer outline
drawing for the total weight of the assembled
transformer.
Location and Mounting
Consult local and national codes to ensure that
the installation meets all applicable requirements.
Location of the transformer must permit it to
operate in conditions that meet the requirements
specified in the “Usual Service Conditions” section
of IEEE Standard C57.12.00. Operation not
meeting these service condition requirements will
compromise transformer capacity and reliability,
unless the transformer is designed specifically
for operation in conditions other than usual
service conditions. Contact the Howard Industries
Transformer Division, if additional information is
needed about location and mounting issues not
covered by these instructions.
The transformer should be mounted on a level
concrete foundation of sufficient strength to
support the weight of the completely assembled
transformer. The transformer should sit flush with
the surface of the pad, so that there are no gaps
that might compromise tamper resistance of the
terminal compartment. The installed transformer
should not tilt in any direction more than three
degrees. Greater tilt may compromise insulation
fluid coverage of live parts within the tank and may
prevent insulating fluid from circulating properly
through the cooling radiators. Improper circulation
of insulating fluid may cause overheating and
reduced transformer life.
The transformer should be located at least 24
inches (710 mm) from any obstruction and
have adequate clearance to allow the terminal
compartment doors to open fully. When installing
transformers designed for indoor operation,
adequate air inlets and outlets must be provided at
the mounting location for proper cooling.
WARNING
FAILURE TO FOLLOW THE INSTRUCTIONS
BELOW MAY CAUSE DEATH OR SERIOUS
PERSONAL INJURY AND/OR DAMAGE TO THE
EQUIPMENT.
• Use a crane, suitable lifting cables or
straps, and a spreader bar to unload the
transformer.
• Do not unload using a forklift. Keep
unnecessary personnel clear while
unloading and moving the transformer.
SECTION 3: INSTALLATION