Howard HI-102 Overhead Transformer - Manual (Page 13)

Document 2.4.95, Revision 0
May, 2013
13
Fluid-Filled Overhead Distribution Transformers
2. Checking for Leaks —Check the tank to make
sure there are no fluid leaks.
3. Observing Operation —After the transformer is
initially energized, visually inspect it to make sure
that no abnormal conditions are observed.
4. Checking Gauges —Observe the fluid level and
fluid temperature gauges (if provided) to confirm
the proper fluid level and temperature.
5. Audible Sound — It is normal for transformers
to emit an audible humming sound, which is
primarily caused by alternating magnetic flux in
the transformer core. Amplitude and harmonic
content of the sound is influenced by transformer
size, the energizing voltage level and sinusoidal
purity, load conditions and acoustic conditions
at the installation site. Refer to NEMA Standards
Publication TR1, Transformers, Regulators and
Reactors, and IEEE Standard C57.12.90, IEEE
Standard Test Code for Liquid-Immersed Distri-
bution, Power, and Regulating Transformers, for
more information about design sound levels and
factory sound testing. Unusual sounds should be
investigated, as this might indicate a potential
problem.