Location - HPS EnduraCoil 1.2 KV Manual De Instrucciones

Dry-Out (continued)

Location

CAUTION
Failure to follow location instructions can result in
injury and/or property damage.
ventilation openings to minimize dust accumulation within
the enclosure. These filters must be removed before the
transformer is put into service. Recommended temperature
should not exceed 105°C (221°F).
4. For dry-out using internal heating through the shorted
terminal method, please contact the transformer
manufacturer for specific instructions. The principles of this
method require to short circuit LV and supply current to
HV no more than 100% of nameplate current rating. The
winding temperature should not exceed 105°C (221°F).
Refer to Field Testing.
5. Variable factors affecting the construction and use of
dry-type transformers makes it difficult to set limits for the
insulation resistance. Experience to date indicates that 2
megohms, (one minute reading at approximately 25°C)
per 1000 volts of nameplate voltage rating, but in no case
less than 2 megohms total, may be satisfactory value for
insulation resistance. Insulation megger test (500 V or
1000 V DC). Test to be done between:
LV to HV + Ground
HV to LV + Ground
Core to Ground
It is emphasized that only specifically qualified personnel
undertake this work.
Transformers that have been exposed to flood conditions,
direct rain or sprinklers, may not be able to be dried
out appropriately. Consult the manufacturer for further
instructions.
Ventilated dry-type transformers are normally designed
for installation indoors in dry locations. They will operate
successfully in the recommended humidity range. It is
necessary to take precautions to keep them dry from
condensation if they are de-energized for longer time periods.
Refer to dry-out instructions. Dry-type transformers covered
by this guideline are designed for operation at altitudes not
exceeding 1000 m (3300 ft.) unless transformer has been
specifically designed for higher altitude.
Environmental Considerations:
Ventilated dry-type transformers should not be located
in environments containing contaminants including dust,
fertilizer, excessive moisture, chemicals, corrosive gases, oils or
chemical vapors. Locations where dripping water is present are
to be avoided. If this is not possible, suitable protection must
be provided to prevent water from entering the transformer
enclosure.
continued on following page
(if the core is isolated)
IOMGCAS / May 2014
9