Amprobe FLEX3 Current-Transducer - Manual (Page 7)

AMPROBE
FLEX3
5
3. POWER SUPPLY
The FLEX3 is a passive transducer and does not require any power supply.
4. HINTS FOR FLEXIBLE CLAMPS USE
All flexible clamps are based on Rogowski's coil principle:
dt
di
M V
coil
 
which shows that the voltage output signal is proportional to the rate of change of current.
In order to get current value, the voltage output signal is integrated electronically.
Typically the voltage output signal is really low and this suggests using shielded cable for
coil connection to instrument's inputs.
WARNING
As the Coil Output connector cannot be perfectly shielded it is
recommended to outdistance it by any Potential source.
5. INSTALLATION
The current probe was designed to allow the operator to connect this measurement device
around a conductor without disconnecting the conductor, as many CTs presently require.
Even though the current probe output is AC, there are instances where the user will want
to orient the transducer so that proper polarity will exist at the output terminals. This is
done by installing the transducer around the conductor with the molded-in arrow on the
latch (see picture 2) pointing in the direction of conventional current flow. Conventional
current flow is defined as current flowing from the generator to the load.
The current probe must be installed with the interconnection cable on the outside of the
loop when the latch is engaged. The polarity arrow, the double insulation, and the warning
symbols will all be on the outside of the loop. It should also be noted that the current probe
would produce twice the output voltage if you wrap the transducer around the conductor
twice.
There is minimal shock hazard using a FLEX3 current probe. Each transducer has been
Hi-Pot tested to several thousand volts with no voltage breakdown. This particular
characteristic allows high-current measurement (with a wide frequency bandwidth) of
conductors at less than 1000V
AC
potential to earth.
WARNING
Hazardous potentials may exist in the vicinity of the desired current
measurements. Use locally approved safety procedures when working near
hazardous potentials. It is recommended not to install the FLEX3 around a live
bus that is at a hazardous potential. If installation is not possible when the bus
is inactive or power is turned off, always use appropriate gloves and/or
equipment approved for working around hazardous potentials when installing
the FLEX3 in the vicinity of these hazardous potentials.
Do not exceed the minimum bending radius of the FLEX3 current transducer when installing
the transducers around the conductors. Exceeding the bending radius will degrade the
measurement accuracy.