Field Testing - HPS EnduraCoil 1.2 KV Manual De Instrucciones

Field Testing

CAUTION
Failure to follow field testing procedures could
result in minor or major personal injury and/or
equipment damage.
RECOMMENDED TORQUE VALUES FOR BOLTED
ELECTRICAL CONNECTIONS
BOLT SIZE CARBON ST.
GRADE 5
ft-lbs [Nm] ±5%
1/4-20 7 [10]
3/8-16 25 [28]
1/2-13 60 [70]
8 mm 20 [23]
12 mm 60 [70]
*Note: The above torque values are for dry, unlubricated bolts.
Installation, Operation, and Maintenance Guide - Cast Resin Transformers
BRASS S.S STEEL
ALLOY CU270 B8 OR B8M
ft-lbs [Nm] ±5% ft-lbs [Nm] ±5%
3.8 [5] 5 [6]
14 [18] 15 [20]
33 [45] 37 [50]
12 [14] 12 [14]
33 [45] 37 [50]
It is recommended that separate field testing and inspection be
performed before placing a transformer in service to determine
that it is in satisfactory operating condition and to obtain data
for future comparison. We recommend to follow the ANSI/IEEE
test procedure as a minimum.
Where low-frequency applied-voltage, insulation resistance
(megger tests) are conducted, the test voltages shall not
exceed 75% of factory test values. When field tests are made
on a periodic basis, it is recommended that the test voltages
be limited to 65% of factory test values. Disconnect surge
arrestors if supplied. It is emphasized that any tests should be
conducted by competent, qualified personnel in accordance
with recognized safety standards and codes, particularly NFPA
70E or CSA Z462.
1. If the transformer has been shut down for a period of
time, it must first be visually inspected for evidence of
condensation, moisture or dust. It must be cleaned and
dried out as described earlier before re-energizing.
2. Fans, motors, relays and other devices should be inspected
to be certain they are working correctly.
Accessories such as lightning arresters must be installed in
accordance with the assembly drawing provided.
3. Verify the selection of taps, as per the nameplate - all tap
jumpers should be in the identical position on each coil
(note: there may be more than one set of taps on a coil).
Tap jumpers may only be changed when the transformer is
de-energized.
4. Some units are provided with winding temperature
monitors. An instruction manual, complete with drawings,
will have been provided. These devices consist of a
temperature indicator and a thermal sensing probes.
Ensure that all parts have been assembled and installed
correctly. Failure to install this sensing probes into the
correct insulated sleeve (thermowell) can result in severe
damage to the transformer. Maintain electrical clearance if
installing sensing probes from the temperature monitor or
terminal block. For winding > 30kV BIL, do not put probe
in the coil unless instructed to do so.
5. Check for tightness and cleanliness of all electrical
connections including taps, phase connections and
grounds.
6. A Megger Test (insulation resistance test) should be
conducted on each transformer to determine the integrity
of the insulation. An insulation resistance test is of value
for future comparative purposes and for determining the
suitability of the transformer for a high potential test. This
test should be completed before the high potential (Hi-Pot)
test, if applicable.
Variable factors affecting the construction and use of
dry-type transformers makes it difficult to set limits for the
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