Compliance West HT-3000P, Instruction Manual

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the Test Return Lead clip from the equipment under test and reconnecting it, taking care to make
a good connection. The unit should then be retested. If a failing result is repeated, the
connection between the power supply cord ground pin and the chassis of the equipment being
tested should be checked and reworked until a passing result is obtained.
*Special calibrations available by internal adjustment. Must be performed by qualified service
personnel. See Sec. 5.
Defeating the Ground Check
The Ground check can only be conducted on equipment using a three wire grounded
power supply cord. Some equipment, such as most portable lamps and all double insulated tools,
have only a two wire power supply cord, so the Ground test cannot be conducted.
Please note that defeating the Ground check should not be done except when
necessary to test two-wire devices. The Ground check feature provides an extra level of
operator safety because high voltage will not be applied if the Test Return Lead is not
properly connected to the exposed dead metal of the equipment being tested. If the Test
Return Lead is not properly connected, a dielectric withstand failure may energize exposed
dead metal. Additionally, the HT-3000P may not recognize the failure. The test will
continue for its normal length of time, and the HT-3000P may show a "PASS".
To allow the HT-3000P to test equipment using a two wire power supply cord, the
Ground Check can be defeated by turning the rear panel Ground Check switch to the Off
position. To remind the operator that the Ground Check is not being conducted, both the green
Ground OK
and red
Ground Open
LED's will be lit continuously during the test. When testing
with the Ground Check switch in the Off position, the operator must ensure that the Test Return
Lead is properly connected to exposed dead metal of the equipment being tested for safety and to
ensure that the HT-3000P properly reports all failures.
Leakage Test
The HT-3000P leakage test uses a separate low-frequency circuit to check for excessive
leakage between primary power components and ground. There is not a specific leakage current
level pass/fail requirement at this time for most equipment, however, higher than normal leakage
current on a particular part may indicate an assembly or component problem in the primary
circuit.
The leakage current is also monitored by the HT-3000P to ensure that excessive leakage
does not keep the tester from developing full voltage required for the high voltage test. The HT-
3000P will provide full voltage at any leakage current level up to 20 mA AC or 5mA DC. The
leakage current trip level is adjustable on the rear panel.
The leakage test is conducted by shorting the power and neutral conductors of the power
supply cord and applying high voltage between them and the exposed dead metal of the chassis
of the equipment being tested.
Excessive leakage current is not grounds for failure of the dielectric withstand test.
Leakage current is a normal result of capacitance in the primary circuit between neutral or line
conductors and ground. (In dielectric tests of some larger electric motors, leakage currents of as
high as 95 mA are considered acceptable by safety agencies.) However, leakage currents higher
than normally anticipated for a particular model should not be ignored. This indicates problems
of low resistance up to a short circuit between line/neutral and ground, and failures should be
investigated. Failure modes are discussed below.