Howard HI-104 Single-Phase Pad Transformer - Manual (Page 13)

Document 2.4.96, Revision 0
March, 2013
13
Single-Phase Pad-Mounted Compartmental-Type Distribution Transformers
pressure relief valve, being careful to avoid any
hot fluid that might be expelled from the valve.
When reinstalling the plug, apply an appropriate
thread sealing compound to prevent a fluid leak.
Be aware that fluid temperature and orientation
of the transformer tank will cause the fluid level
to vary. Transformers are filled to a level that
corresponds to a fluid temperature of 25°C. The
actual fluid level will increase with increasing
temperature. The fluid level indication will also
vary when the transformers is not installed in a
level orientation.
8. Fluid Temperature—Observe the fluid tempera-
ture gauge and make sure the temperature is
no lower than indicated below before the unit is
energized.
-20°C (-4°F) for conventional transformer oil
and silicone fluid
0°C (32°F) for R-Temp fluid
-10°C (14° F) for natural ester fluid
9. Internal Fault Detector—If the transformer is
provided with an Internal Fault Detector (IFD),
remove the red shipping lock after installation
and before placing the transformer into service.
10. Current Transformers—If current transformers
(CTs) are present, connect CT leads to the meter-
ing load. If CT leads are not connected to a me-
tering load, they must be shorted together and
grounded before the transformer is energized.
11. Accessory Wiring—Check wiring of control and
alarm circuits (if provided) to make sure there
are no loose connections and no damage to wire
insulation.
12. Tank Finish—Check all painted surfaces to make
sure that there is no damage or corrosion.
13. Tools—Check to make sure that all tools and
equipment are accounted for.
14. Internal Inspection— Transformer tanks are
sealed at the factory and should not be opened
unless necessary. Single-door style transformer
tanks are fully welded and are not accessible
except through bushing openings. Double-door
style transformer tanks are accessible through
a bolted handhole located on the tank cover. If
the transformer tank must be accessed, refer to
“Opening the Transformer Tank” for instructions.
Post-Energization Inspection and Tests
After the transformer is energized, the following tests
and inspections should be performed.
▲
! DANGER
FAILURE TO FOLLOW THE INSTRUCTIONS
BELOW WILL RESULT IN DEATH OR SERIOUS
PERSONAL INJURY, AND COULD ALSO RESULT
IN DAMAGE TO THE EQUIPMENT .
Be aware of dangerous voltages within the ter-
minal compartment and avoid personal contact
with live terminals.
▲
! WARNING
FAILURE TO FOLLOW THE INSTRUCTIONS
BELOW COULD RESULT IN DEATH OR SERIOUS
PERSONAL INJURY, AND COULD ALSO RESULT
IN DAMAGE TO THE EQUIPMENT.
• Energize the transformer from a remote loca-
tion.
• Only qualified personnel with appropriate
equipment should measure transformer volt-
ages.
• Wear personal protective equipment (PPE)
to prevent injury from potential arc-flash or
contact with dangerous voltages.
• Make sure the transformer is securely and
effectively grounded at all times.
• Insulated dead-end caps or plugs must be
installed on all unused dead-front high-volt-
age bushings. Dust caps must not be used in
place of insulated dead-end caps or plugs.
• Current transformer (CT) leads must be con-
nected to a metering load or shorted together
and grounded to prevent dangerous voltage
at the CT terminals.
1. Verifying Correct Voltage—Before supplying volt-
age from the transformer to the load, verify that
the secondary voltage is correct. Using a suitable
AC voltmeter, measure the voltage of the sec-
ondary windings and make sure they agree with
the secondary voltage listed on the transformer
nameplate.