PowerTek PA2553, User Manual, Page: 28 / 88

28
PA2553
User's Guide
External Transducer Connections for Test
Connections are similar to those shown in the internal current transducers, however, only
the SOURCE, Phase and Neutral connections need be directly made to the
PA2553
. Pass
each phase current conductor to the load through an external current transducer. Connect
the output of the transducer to the respective BNC terminal on the
PA2553
rear panel.
Note the following -
•
Each of the “Live” phase connections should be passed through current transducers.
Thus 1 transducer is required for 1-phase 2-wire (phase A), 2 for 1-phase 3-wire
(phase A and B), and 3 for 3-phase 3-wire or 4-wire configurations.
•
Take special care that the same phase is connected to each respective SOURCE
terminal as that for which the current transducer output is connected to the respective
BNC terminal.
•
If the power analyser unexpectedly displays negative watts indications, this is an
indication that the current flow in the transducer is reversed. Either the wire is
reversed in the transducer, or the transducer output has the incorrect polarity. This
may be resolved by correcting the wiring or by setting the current input scale factor
in the power analyser to a negative polarity.
•
If a transducer is being used, which does not have DC current capability, then AC
Only input coupling should be chosen in the Measurements Setup screen.
•
If a transducer is being used, which has DC current capability, and the user desires to
measure any DC current content, then
AC & DC input coupling should be chosen in
the Measurements Setup screen of the power analyser. The user should perform
the DC offset correction procedure as described on page 65, after making the
connections and allowing the external transducer to settle after application of its
power.
•
Particularly when operating at low current levels, it may be important to ensure that
the voltage signals cannot capacitively couple into the current transducer outputs.
The use of flexible coaxial cable is recommended for the current transducer output
wiring.