Megger L1070, Инструкция по эксплуатации

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M
AVTM651070 Rev B Nov 2006
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8 kHz takes the best of both high and low frequency. This mid range frequency
is not very susceptible to bleed off or coupling, but it can jump impedance on
the utility better than the 815 Hz. It is still best to use 815 Hz, but 8 kHz is one
of the most common frequencies used to locate coaxial cable and telecom pairs.
The 82 kHz (higher frequency) is sometimes better than the 815 Hz (lower
frequency) for locating sharp corners in cables or pipes. The 82 kHz signal is also
better for jumping” disconnected shield bonds or grounds, or tracing signal may
indicate one of these characteristics. The locating range is quite short for the 82
kHz signal so the TRANSMITTER must be repositioned more often during the
tracing operation. This FREQUENCY is also useful for applying a signal using
the FLEXICOUPLER OR THE HARD COUPLER..
Continuously Grounded Circuit
The locating range for bare uninsulated cable and pipe is typically 300 ft (91.4 m).
If the locating range on a particular pipe seems unusually short, there may be an
insulating bushing in the buried pipe. Try to bypass the insulated bushing by
connecting the transmitter to a location on the pipe that is past the bushing.
For pipe - connect the red test lead to the shutoff valve wrench surface or union
fittings near the gas or water meter. For cable - connect the red test lead to any
point on the bare neutral. See Figure 9.
Place a ground rod approximately 10 ft (3 m) from this point, along a line that is
perpendicular to the buried pipe or cable. Insert the ground rod 8 to 10 in. (20.3
to 25.4 cm) into the ground. Connect the black test cord to the ground rod.
Plug the red/black test cord into the TX OUTPUT jack. Set the FREQUENCY
switch to AF. The LOADING indicator light will start blinking after the
transmitter is turned on.
Turn to the Receiver Operation section to begin locating the cable or pipe.
Figure 9: Continuously Grounded Circuit