Ventilation; Accessibility; Transformer Sound Levels - HPS DQT Guía De Instalación Y Operación

Installation (continued)

Ventilation

WARNING
Failure to follow the ventilation instructions can
result in death, serious injury or property damage.

Accessibility

CAUTION
Failure to follow accessibility instructions can result
in injury and/or property damage.

Transformer Sound Levels

Encapsulated Low Voltage Transformer
Encapsulated transformers are required to be installed
in an area where they can be cooled by means of the free
circulation of air where the average ambient temperature is
30°C (86°F) and should not exceed 40°C (104°F) at any time
unless low temperature rise designs are selected.
Adequate ventilation is essential for transformers to
meet their nameplate kVA capability. Multiple encapsulated
transformers should be located at least 2 inches apart on
units up to 10kVA and at least 4 inches apart on units over
10kVA, away from any other obstructions to allow free, clean
circulation of air.
NEC standards require that transformers be accessible for
inspection and located accordingly.
However, transformers should not be located in areas
where stored items are likely to interfere with either natural air
convection or the capability to have them inspected. Passage
ways or other areas where people could be exposed to live
parts during inspection should also be avoided.
Adequate protection should be provided under any
circumstances.
Transformers are an electrically energized apparatus and
by their nature during normal operation will emit a certain level
of sound.
Transformers are required to meet NEMA standards for
the maximum sound levels permissible. These sound level
standards vary from 40 to 67 dB and as such may be an
annoyance if located in close proximity to where people work
or reside.
Care should therefore be exercised in selecting sites
for transformers particularly in sensitive areas like hospitals,
classrooms, medical or office facilities.
The following guidelines may be helpful:
Units should be mounted away from corners or reflecting

walls or ceilings.
Flexible conduit should be considered to make the

incoming/ outgoing connections.
Depending on the environment, to reduce noise

acoustically absorbing materials could be considered for
walls and ceilings around the unit.
The location of the unit should be as far as practical

from areas where sound levels could be considered
undesirable.
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