ETS-Lindgren 94456 Current Probe (Archived) - Manual (Page 10)

Installation MODEL 94456 CURRENT PROBES
6 © EMC TEST SYSTEMS, L.P. – MARCH 2002
REV B – PN 399265
conditions, several measurements taken along the line will
provide a complete picture of the RF current distribution
and amplitude.
INSTALLATION
The window (aperture) of the probe will accommodate
cables up to a maximum outside diameter of 4.0 inches.
After placing the probe around the conductor(s) to be
measured, the probe jaws should be carefully locked. If this
is not done, inadequate shielding or incorrect air gap will
result and the measurement will not be accurate.
The connecting cable used between the current probe and
the EMI test equipment must have a 50 Ohm characteristic
impedance and matching cable connectors. The current
probe is calibrated for use only with a 50 Ohm load.
Therefore, the EMI test equipment must have a 50 Ohm
input impedance. Precautions regarding minimum bending
radius should be observed when installing and using the
cable. For long cables and at high frequencies, cable loss
may also be a factor. Care should be taken to use low loss
cables and to perform cable loss corrections if necessary.
The probe rejection of any external pickup from conductors
not passing through the window is better that 60 dB. The
presence of very strong magnetic fields will likely have an
effect on probe sensitivity. Care must be taken not to place
the unit close to permanent magnets or the magnetic field
structures of motors or generators.
Archived 6/1/10