Safe Probing
N2780/1/2/3B User’s Guide
19
NOTE
Under certain circumstances, oscillation may occur if the probe is
connected to the N2779A power supply while the power supply is on.
This does not indicate a malfunction. Oscillation can be stopped and
operation restored to normal by opening and closing the sensor head.
NOTE
Depending on the amplitude and frequency of the current being
measured, the sensor head may emit a resonant sound. This sound may
also occur during a demagnetizing operation, but it does not represent a
malfunction (device failure).
NOTE
If foreign matter becomes adhered to the facing surfaces on the sensor
head so that a slight gap exists between the upper and lower sensors,
the sensor head may emit a resonant sound. Any foreign matter should
be removed using the cleaning method described in this manual.
NOTE
An increase in the volume of the resonant sound during use may indicate
that the gap between the upper and lower sensors has increased in size.
Since the sensor characteristics may change, it is recommended to
calibrate the device. (See
“Returning the Probe for Service”
NOTE
The reading may be affected by the position within the clamp aperture of
the conductor being measured. The conductor should be in the center of
the clamp aperture.
NOTE
When carrying out a measurement, press the opening lever until the
UNLOCK
indication disappears and check that the sensor head is
properly closed. If the sensor head is not properly closed, an accurate
measurement is not possible.
NOTE
Accurate measurement may be impossible in locations subject to strong
external magnetic fields, such as transformers and high
current
conductors, or in locations subject to strong external electric fields, such
as radio transmission equipment.
