Howard HI-102 Overhead Transformer - Manual (Page 7)

Document 2.4.95, Revision 0
May, 2013
7
Fluid-Filled Overhead Distribution Transformers
additional items may arrive on separate
pallets. Claims for shortages or errors
must be noted on the shipping documents
and reported immediately to the Howard
Industries Transformer Division. Failure
to make a timely claim will constitute
unqualified acceptance and a waiver of all
such claims by the purchaser.
3. The tank vacuum/pressure gauge, if
provided, may indicate a positive or negative
reading when the transformer is received,
depending on the relative temperatures of
the fluid and ambient air. A rising or falling
reading that varies over time with ambient
temperature indicates that the transformer
tank is sealed effectively. If the vacuum/
pressure gauge shows a constant zero
reading, this indicates the possibility of a
tank leak. If this occurs, the tank should be
checked carefully for leaks as indicated in
the following step.
4. Check the tank for indication of fluid leaks,
looking carefully at weld seams, bushings,
gauges, valves and all other tank fittings. If
suspicious indications are found, investigate
thoroughly to determine if a leak does exist
on the transformer. Indications of a leak
can sometimes be residual fluid that was
not cleaned completely during the filling
process and not an actual leak. In many
cases a small pinhole tank leak or leak
from a bushing, gauge, valve or other fitting
can be easily repaired on site. Refer to
the “Maintenance and Repair” section for
information about the repair of fluid leaks.
5. Check for external damage including
dents or scratches on the tank walls and
radiators, if present. Dents and scratches
can often be repaired on site using simple
touch-up procedures. If touch-up painting
is performed, do not remove or obscure
any warning labels, instructional labels or
nameplates.
6. Check for broken, cracked, or damaged
bushings, gauges, valves and other fittings
and accessories.
7. Check for missing or damaged component
parts and for packages that shipped
separately from the transformer.
Fluid Level
The transformer is shipped from the factory with
insulating fluid filled to the proper level. Before
energizing the transformer, verify proper fluid level
by observing the fluid level gauge, if provided. The
fluid level gauge pointer should be between the
“High” and “Low” marks. For transformers provided
with a fluid sight plug, the fluid level can be directly
observed if it is within acceptable range.
When checking the fluid level, be aware that it is
normal for the level to vary as a function of fluid
temperature. A transformer found to have an
unusually low fluid level should be checked for
potential leaks and filled to the proper level with
the same type of liquid as that specified on the
transformer nameplate. Refer to “Filling with Fluid.”
Internal Inspection
An internal inspection of the transformer tank is
rarely necessary and is recommended only when
there are obvious indications that the transformer
has received severe impact damage during transit
or when necessary to perform recommended pre-
energization tests or inspections. Do not open
the transformer tank without authorization from
the Howard Industries Transformer Division. If the
transformer tank must be opened, refer to “Opening
the Transformer Tank” for instructions.
Fluid Sampling
Sampling and testing of the fluid is not required
unless there is indication that moisture or other
contaminants have accidently entered the tank
during transit. If moisture or contaminants in the
fluid is suspected, contact the Howard Industries
Transformer Division immediately for instructions.
If fluid sampling is required, refer to “Sampling the
Fluid” for instructions.
Transformer Storage
Transformers may be temporarily stored if properly
prepared. It is recommended that transformers
be stored completely assembled. Prior to storage,
transformers should be thoroughly inspected as
described above in the “Initial Inspection” section.
If the transformer is not completely assembled,
separate components and accessories should be
stored in a clean dry area in their original shipping