4
GMC-I Messtechnik GmbH
3
Performing Measurements
The probe should be calibrated on a regular basis in order
to assure flawless functioning and measurement accuracy.
Due to the fact that the nickel iron core used for types
B
F and Clip 0100S is highly sensitive to impact, special
attention must be paid during measurement, storage and
transport: Powerful impacts and vibration must be
avoided.
Make sure that the secondary circuit is connected to the
measuring circuit at the measuring or recording instrument
first. Observe the safety precautions listed in chapter 1, as
well as the specified allowable output load range for the
respective clip-on transformer. Observe correct phase
sequencing for k and l at the measuring instrument for
power measurements.
Type A and D probes are equipped with a current output
and are connected to the current measurement inputs (e.g.
300 mA). Before closing the probe around the current con-
ducting cable, check the secondary circuit, as well as the
measurement input at the measuring instrument with an
ohmmeter if necessary: Neither circuit may be interrupted!
Do not enclose the primary conductor with the clip until
after this test has been performed. The measurement value
is calculated by multiplying the displayed value by the
transformation ratio, or the appropriate transformation ratio
can be selected at the measuring instrument (e.g.
METRA
HIT
B
ASE
,
METRA
HIT
T
ECH
or
METRA
HIT
T-
COM
).
Be sure to remove the clip from the primary conductor
before the connections at the measuring instrument are
disengaged.
Probe types B, C, E, F and Clip 0100S convert primary
current into a proportional output voltage, and must there-
fore be connected to the voltage measurement input (mV
or V) at the measuring instrument.
