HPS EnduraCoil 1.2 KV Manual De Instrucciones página 15

Field Service (continued)
2. Noise and Vibration
Sound levels for power transformers can vary from 60 dB(A)
for a 500 kVA to 76 dB(A) for a 10000 kVA. These sound levels
are determined by national standards and are based on the
following:
 values are for a non-loaded condition
 tested in a low ambient noise environment
 walls or reflecting surfaces at least 10' [3m] away from
all sides of the transformer.
Transformers that are installed in more confining electrical
rooms, when connected to the load, will exhibit higher (than
standard) sound levels. Excessive noise can be caused by:
 high input voltage
 high frequency
 unbalanced loads
 excessive load current
 voltage and current harmonics from non-linear loads
 loosened core clamps
 hardware or enclosures loosened due to shipping or
handling
 shipping plates are not removed
 anti-vibration pads are not installed
Transformers will exhibit higher than normal sound levels if
installed on suspended floors that may resonate. It is a good
practice to install power units on the ground floor or basement
level to avoid suspended floors. Vibration dampeners or
spring isolators are recommended to attenuate sound levels.
Additionally, flexible connectors should be installed between
the bus bars and other equipment to avoid vibration transfer.
Transformers installed in close proximity to each other can also
experience a resonant frequency between them that will result
in higher than normal sound levels.
3. Reduced or Zero Voltage
Loose connections on transformer terminals or terminal
boards, broken lead wires or shorted turns are all possible
sources. As well, reduced output voltage may be from an
incorrectly selected tap position.
4. Excess Secondary Voltage
Can be caused by higher input voltage or an incorrect tap
position.
5. Smoke from Transformer
Smoke and/or fumes on initial start-up is common and is the
result of oils and lubricants used in the manufacturing process.
The smoke is considered an irritant and should be temporarily
ventilated. It is not a long term health risk and should
dissipate after 24 hours of loading.
continued on following page
15
IOMGCAS / May 2014