Megger PAT4DV/3, Руководство пользователя

Страница: 38 / 51

38
Description of Tests
Earth Bond Test
In order to adequately test the integrity of the appliance earth conductor, high current (10A or 25A a.c.) is passed between the Earth Bond terminal and
the appliance test socket earth pin. The current may be set to 10A or 25A (calibrated at 0.1). The
PAT4 can store upto three separate earth bond test
results for each asset test.
The
PAT4 contains thermal overload protection, which may operate in extreme cases of repeated earth bond testing. The message “Bond test is too
hot” will be displayed and the test will be aborted. Testing may recommence after a 10 minute cooling period. If this occurs frequently, refer to Settings
and reduce the Earth Bond test time. We recommend a duration of 5 seconds for this test.
1 Connect the bond lead to a suitable point on the asset under test. Press the OK key.
2 When the test finishes the final result is shown. If the result is OK , press PASS ,
then to store the result press
LOG
.
If subsequent Bond tests are not required press the
SKIP
key when prompted to connect
the Bond lead again.
3 If the Bond resistance is too high, press the FAIL key. If the asset has a long supply lead you can
compensate the Bond reading to allow for this by pressing the COMP key. To fail the asset immediately,
press the LOG key.
4 Enter the lead length in metres.
5 Use the Up/Down keys to select the cross sectional area of the earth conductor.
6 The Bond Resistance is re-displayed taking into account the supply lead resistance.
Press
PASS
or
FAIL
as appropriate.
Earth Continuity Test
This test provides a measurement of protective conductor resistance and is therefore applicable to Class 1 assets only. This test is usually applied to
equipment which may be damaged by the high current Bond test (e.g. I.T. equipment).
A low current (D.C.) is passed between the Continuity terminal and the appliance test socket Earth pin. The test current is limited to 200 mA with a
maximum open circuit voltage of 4 V. To use this test the Continuity terminal and the black lead should be connected to the appliance’s exposed
metalwork. On completion of the Continuity test, ensure that the black earth lead is disconnected from the appliance under test.
The procedure for this test is very similar to the Bond test (some screen titles are changed).
10A Bond Lead
Connected? YES
Bond Resistance
FAIL* 0.069
Ω
PASS
Wire mm 2
1.0 (10A)
Lead length (m)
10
Fail or retest COMP
RETEST LOG
Bond Resistance
FAIL* 0.284
Ω
PASS
Pass or retest
RETEST LOG
10A Bond Lead SKIP
Connected? YES