Howard HI-102 Overhead Transformer - Manual (Page 12)

Document 2.4.95, Revision 0
May. 2013
12
Fluid-Filled Overhead Distribution Transformers
voltage switch is in the parallel position. Before
removing the cover or handhole cover, refer to
“Opening the Transformer Tank” for instructions.
5. Grounding—Check to ensure that the trans-
former tank is securely and effectively grounded.
The transformer tank ground pad or nut is
located on the tank.
6. Bolted Connections—Check all bolted connec-
tions for tightness, referring to nominal torque
guidelines contained in Tables 1 through 4.
7. Fluid Level—Check to make sure the fluid level
is correct as indicated by the fluid level gauge
or sight plug, if provided. Be aware that fluid
temperature and orientation of the transformer
tank will cause the fluid level to vary. Transform-
ers 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 transform-
ers 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 FR3™ fluid
9. Internal Fault Detector—If the transformer is
provided with an Internal Fault Detector (IFD),
remove the orange shipping lock after the trans-
former is installed and before it is placed into
service.
10. Current Transformers—If current transform-
ers (CT’s) are present, connect CT leads to the
metering load. If CT leads are not connected to
a metering load, they must be shorted together
and grounded before the transformer is ener-
gized.
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. Internal Inspection—Transformer tanks are
sealed at the factory and should not be opened
unless necessary. 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
terminal 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
location.
• Only qualified personnel with appropriate
equipment should measure transformer
voltages.
• 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.
• Current transformer (CT) leads must be
connected to a metering load or shorted
together and grounded to prevent dangerous
voltage at the CT terminals.
1. Verifying Correct Voltage —Before supplying
voltage from the transformer to the load, verify
that the secondary voltages are correct. Using a
suitable AC voltmeter, measure the voltage of the
secondary windings and make sure they agree
with the secondary voltages listed on the trans-
former nameplate.