Instruction Manual

Document 2.4.96, Revision 0
March, 2013
29
Single-Phase Pad-Mounted Compartmental-Type Distribution Transformers
9. Inspect the base of the terminal compartment
and make sure that it is sitting level and at on
the mounting pad with no gaps that might com-
promise tamper-resistance.
10 Check bushings, gauges, switches, fuse holders,
valves and all other accessories for proper opera-
tion and repair or replace any defective devices.
11. Check all fasteners for signs of corrosion and
replace as necessary.
12. Check to make sure the uid level is correct as
indicated by the uid level gauge or sight plug,
if provided. Be aware that uid temperature and
orientation of the transformer tank will cause
the uid level to vary. Transformers are lled to
a level that corresponds to a uid temperature
of 25°C. The actual uid level will increase with
increasing temperature. The uid level indica-
tion will also vary when the transformers is not
installed in a level orientation. If the uid level is
low, add uid according to the instructions in the
“Filling with Fluid” section.
13. Check the uid temperature gauge (if present),
including the maximum temperature drag hand
(if provided) to determine whether the uid tem-
perature has exceeded the design limit. Any such
indication should be investigated to determine
and correct the cause. Reset the drag hand.
14. Check the torque values on all electrical con-
nections, including all ground connections and
tighten as necessary. Refer to the torque guide-
lines contained in Tables 1 through 4.
15. Replace any damaged or unreadable name-
plates, instructional labels, and safety labels.
16. If it is suspected that water or other contami-
nants may have entered the tank, the uid
should be tested to determine its condition. For
transformers lled with conventional transformer
oil, Refer to IEEE Standard C57.106 Guide for
Acceptance and Maintenance of Insulating Oil
in Equipment. For transformers lled with less-
ammable high molecular weight hydrocarbon
insulating uid (such as R-Temp), refer to IEEE
Standard C57.212 Guide for Acceptance and
Maintenance of Less Flammable Hydrocarbon
Fluids in Transformers. For transformers lled
with natural ester uid (such as Envirotemp FR3),
refer to IEEE Standard C57.147 Guide for Accep-
tance and Maintenance of Natural Ester Fluids in
Transformers. For transformers lled with sili-
cone uid, contact the Howard Industries Trans-
former Division for testing recommendations.
Electrical Tests
The following electrical tests can be used to deter-
mine the condition of the transformer. Follow the
instructions and precautions provided by the test
equipment manufacturer. Contact the Howard Indus-
tries Transformer Division to discuss any of these
tests.
▲
! 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 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.
• De-energize the transformer and ground all
transformer terminals.
• Only qualied personnel with appropriate
equipment should perform these tests.
• Wear personal protective equipment (PPE)
to prevent injury from potential arc ash or
contact with dangerous voltages.
• Make sure the transformer tank is properly
grounded at all times.
• After testing is complete and the transformer
has been reconnected to the line leads, ener-
gize the transformer from a remote location.
1. Insulation Resistance Test. Refer to “Insulation
Resistance Test” for instructions.
2. Turns Ratio Test. Refer to “Ratio Test” for instruc-
tions.
3. Insulation Power Factor Test. Refer to “Insulation
Power Factor Test” for instructions.