Megger LRCD200 series, Руководство пользователя

Страница: 16 / 28

Possible sources of error
Measurement results can be affected by the following:
1. Significant operating errors can occur if loads, particularly rotating
machinery and capacitive loads are left connected during tests.
2 A poor connection to the circuit under test.
AUTO RCD TEST
AUTO test will run the 1/2I, I & 5I plus 0º and 180º tests automatically. The
operator can stand by the RCD to reset it when it trips on the I & 5I tests.
1. Connect to the circuit as per the 1/2I test.
2. Select the RCD current rating on the top range knob and the AUTO
function on the lower range knob.
3. Press the TEST button to start the test. The lock symbol will flash to
indicate a AUTO test sequence is running, and the display will show ‘t1’
to ‘t5’ to indicate which test is running.
t1 = 1/2I, t2 = I at 0º, t3=I at 180º, t4= 5I at 0º and t5= 51 at 180º
4. Reset the RCD each time it trips.
5. On completion of testing the results can recalled by repeatedly pressing
the 0º/180º button.
To indicate each test result, segments of the bar graph are displayed as
below:
none = 1/2I test
I = 1xI test
IIIII = 5 I test
Example shows 5I on 0º
NOTE:
The current limit for the 5I test is 100 mA, as the test current
available is limited to 1 Amp.
0° or 180° testing
Both the [1 x I] and [5 x I] tests should be performed for 0° and 180°.
Repeat the 1 x I and 5 x I tests as above but with the instrument set to
180°.
0° or 180° is selected by pressing the [0°/180°] and the greatest trip time
for each test should be recorded.
RampTest (LRCD220 only)
The RCD trip current is measured by applying a test current of half the
rated trip current and increasing this every 200 ms. When the RCD trips,
the current flowing is recorded and displayed in mA.
1. Select the appropriate RCD rated current on the top range knob.
2. Select the RAMP test on the lower range knob.
3. Press the [TEST] test button
4. The RCD should trip and the trip current will be is displayed.
5. If the RCD fails to trip, >***mA is displayed where *** mA indicates
the maximum RCD tripping current allowed and will vary depending on
range selected.
DC Sensitive RCD test [RCD ]
D.C. sensitive RCDs are tested as per standard RCDs. The RMS current
used is
√
2 x the rated operating current of the RCD.
As with the normal RCDs, these should be tested at 0° and 180°, or in the
case of DC sensitive RCDs, positive and negative.
16