3M 2550 Manuale Utente
78-9000-0192-2 Rev C
39
12. Locating Buried Sheath Faults And Earth
Return Faults
(3M
™
Dynatel
™
Models 2573 and 2573-iD only)
Note: Remove (disconnect) both the near-end and far-end grounding from the test
section.
A. Transmitter Setup
Note: Do not make any connections while the transmitter is on. Fault location will not
work unless the near-end and far-end grounds are disconnected.
Note: This method only works on direct buried cables/conductors. It will not work if
Note: This method only works on direct buried cables/conductors. It will not work if
the cables/conductors are faulted inside of a conduit, such as a PVC conduit.
Step 1. Attach the red clip to the earth-faulted conductor of the cable or conductor
Step 1. Attach the red clip to the earth-faulted conductor of the cable or conductor
under test.
Step 2. Place the ground rod behind the transmitter and in parallel with the target path.
Step 3. Connect the black clip to the ground rod behind the transmitter.
Step 4. Press and hold On/Off [1] to perform a battery test.
Step 5. Press on [T-2] once to power on the transmitter. This will place the transmitter
Step 3. Connect the black clip to the ground rod behind the transmitter.
Step 4. Press and hold On/Off [1] to perform a battery test.
Step 5. Press on [T-2] once to power on the transmitter. This will place the transmitter
in Ohm-meter mode. An Indicator Flag will be displayed above the ohm
symbol, Ω, in the Digital Display [T-4].
− The resistance of the fault will be displayed in ohms on the transmitter
Digital Display [T-4].
− Resistance less than 50KΩ = Significant fault exists
− Resistance 50KΩ to 1.0MΩ = High resistance fault exists (May or may not
cause problems yet, but gets worse with time.)
− Resistance greater than 1.0MΩ = No significant fault exists
Note: The fault locating limit is 2.0MΩ, although the transmitter's ohm-meter mode
can display a fault resistance up to 10MΩ.
Step 6. Press on [T-2] again, to select Fault mode.
Step 6. Press on [T-2] again, to select Fault mode.
− An Indicator Flag will be displayed above the fault locating symbol in the
Digital Display [T-4]. (as shown in the illustration below)
off
+
-
o
Trace
on
on
Output Level
Dynatel
TM
2573
Flag
Note: Two active line locating frequencies, 577 Hz and 33 kHz, are simultaneously
transmitted with the fault finding signal. This allows convenient switching back and
forth between fault finding mode and cable/pipe locate mode on the receiver during
fault finding without returning to the transmitter. The transmitter display [T-4] will
flash between 577 Hz and 33 kHz. It does not display the fault finding frequencies.