UFC 3-535-01
17 November 2005
obtaining the desired voltage, either the circuit being tested or the test set is defective
and should be corrected before the test is continued. Maintain a log book of the circuit
readings and pass this on to the maintenance section for airfield lighting.
14-5.2.7
On new circuits, a megger test check should be made immediately after
the circuit has passed the high voltage tests. This megger reading then can be used by
maintenance personnel for a comparison with further readings to determine the circuit
conditions. Ambient temperature and weather conditions should be recorded at the time
of test.
14-6
CONSTANT CURRENT REGULATOR INSPECTION
Each constant current regulator must be inspected to ensure that porcelain bushings
are not cracked, no shipping damage has occurred, connections are correct, switches
and relays operate freely and are not tied or blocked, fuses (if required) are correct, and
the oil level of oil-filled regulators is correct. Only relay panel covers must be removed
for this inspection; the main tank of oil-filled regulators need not be opened. Information
on the regulator instruction plate must be followed. All covers must be cleaned and
tightly replaced after inspection and tests are completed. (See also checklist for vault
Table 14-8.)
14-7
REGULATOR ELECTRICAL TESTS
The supply voltage and input tap must be checked to see that they correspond:
14-7.1
With the load disconnected, energize the regulator once and see if the
open-circuit protector de-energizes the regulator within 3 seconds.
14-7.1.1
Connect the load circuit (after it has been tested for opens and grounds as
specified in paragraph 14-5 and inspected to ensure all fixtures are properly lamped).
Using only an ammeter, calibrated with an accuracy of 3 percent,
14-7.1.2
measure input voltage and output current simultaneously at the highest brightness step.
Note that when measuring output voltage, the accuracy can be less since the potential
transformer to be used will have some built-in tolerance. Following are suggestions to
ensure successful measurements:
14-7.1.2.1 Use proper equipment. Laboratory quality instrumentation generally give
readings within 1 percent accuracy, while standard grade multimeters, potential
transformers, and current transformers may have more than 5 percent error.
14-7.1.2.2 Suggest using power analyzers with a scaling feature allowing for internal
conversion of current transformer and power transformer ratios, eliminating need to
multiply in power transformer and current transformer ratios. The phase relationship
between the power transformer and current transformer secondaries will affect the
reading if not connected properly (in phase) to the power analyzer, and watts and volt-
amperes (VA) will fluctuate or indicate low. If this occurs, simply swap polarity on either
power transformer or current transformer secondary at the connection to the power
analyzer.
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