Howard HI-102 Overhead Transformer - Manual (Page 22)

Document 2.4.95, Revision 0
May. 2013
22
Fluid-Filled Overhead Distribution Transformers
These instructions are intended as a general guide
for the maintenance and repair of Howard Industries
fluid-filled overhead distribution transformers,
when used in typical applications and operated in
normal environments. Although every effort has
been made to ensure accuracy and completeness,
these instructions do not address every conceivable
application or circumstance that might be
encountered.
Transformers should be inspected periodically while
in service, with the frequency determined by service
conditions. Transformers operating in unusual service
conditions should be inspected more frequently. Refer
to IEEE Standard C57.12.00 for a discussion of usual
and unusual service conditions.
Accessories such as pressure relief valves,
temperature gauges, fluid level gauges, pressure-
vacuum gauges and drain valves typically require
no maintenance, except replacement in the event
of damage. Gauges, if present, should be checked
periodically to make sure they are operating properly.
▲
! WARNING
FAILURE TO FOLLOW THE INSTRUCTIONS
BELOW COULD RESULT IN DEATH OR SERIOUS
PERSONAL INJURY, AND COULD ALSO RESULT
IN DAMAGE TO THE EQUIPMENT.
• De-energize transformer from a remote
location before performing any inspection or
maintenance work.
• Make sure all transformer terminals and
bushings have zero voltage.
• Make sure that the transformer is properly
grounded.
• Fluid leaks should be repaired as soon as
they are discovered.
Periodic Inspection
All exterior surfaces and the transformer
surroundings should be inspected periodically.
Inspection frequency should be governed by
operating conditions at the installation site. More
severe conditions indicate the need for more
frequent inspection.
Inspection Checklist
While observing the safety instructions above,
perform the following checks.
1. Inspect for dents or other damage to metal
surfaces and make necessary repairs.
2. Inspect the paint finish for damage, corrosion
or weathering that exposes the primer coat or
bare metal. Repair any paint damage that might
be found. Refer to “Exterior Paint Finish” for
instructions.
3. Inspect thoroughly for evidence of fluid leaks,
including tank, radiators, bushings, gauges,
switches, valves and all other accessories and
fittings. Check the fluid level and add fluid as
necessary to ensure that the proper fluid level
is maintained. Refer to “Filling with Fluid.” Fluid
leaks must be repaired immediately to prevent
serious damage to the transformer and danger to
life. Refer to “Fluid Leaks” for instructions.
4. Visually check all gaskets for cracking or other
signs of deterioration, and replace as necessary.
When replacing a gasket, carefully clean mating
surfaces to remove any rust, dirt, transformer
fluid, old gasket material, or other contamination
that might prevent a good seal. Use an
appropriate gasket cement when installing new
gaskets. Do not reuse old gaskets.
5. Maintain a clean and unobstructed area around
the transformer, including sufficient clearance
around radiator panels, if present, to ensure
adequate cooling of the transformer.
6. Check bushings, valves, gauges, switches and
all other accessories for proper operation, and
repair or replace any defective devices.
7. Check all fasteners for signs of corrosion and
replace as necessary.
8. Check the fluid temperature gauge, if present,
including the maximum temperature drag hand,
if provided, to determine whether the fluid
temperature has exceeded the design limit.
Any such indication should be investigated to
determine and correct the cause. Reset the drag
hand.
9. Check to make sure the fluid level is correct as
indicated by the fluid level gauge or sight plug,
SECTION 7: MAINTENANCE AND REPAIR