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9.3
Phase Reference
A phase reference is required by the CableData Collector to improve the data analysis and
allows classification of events based on the phase position. A phase reference can be
supplied to the CableData collector by one of two sources, either via the phase reference
transformer or the connected RFCTs. A phase reference on the Auxiliary channel from the
phase reference transformer is the preferred source for the phase reference, but if the
instrument detects it is not present it will attempt to locate a phase reference from the
connected RFCT's.
9.3.1
Transformer Reference
The supplied phase reference transformer is the preferred source for a phase reference
signal, as it will provide better results than using the RFCT's. Because of this, it should be
used wherever possible. To use the Transformer Reference, plug the BNC connector from
the end of the transformer cable into the Aux input.
If the attached cable is too short, it is possible to use either a mains extension lead or a
longer BNC terminated coaxial cable from the phase reference transformer to the
instrument. EA Technology can supply the recommended parts, please contact
EA Technology Product Support for further information. For contact details please see
section 19 of this manual.
The phase reference transformer input is in the form of an IEC320-C7 power cable, which
can be swapped for an off the shelf version of the cable with a local plug. If this is not
possible, the transformer will work with basic travel adapters. The more complex travel
adapters that also convert the voltage may not work and should be avoided. The transformer
is designed to work with an input voltage between 100V and 240V.
9.3.2
RFCT Reference
The CableData Collector will attempt to obtain a phase reference from the sheath current
flowing through the RFCTs. This 50Hz or 60Hz current is due to the cable capacitance, or in
some circumstances may be down to induction from the phase conductors. A current of
approximately 200mA is required to give a reliable reference - if the current is lower, the
reference may be intermittent and unreliable. If the current is around the lower limit, the
phase reference LED may occasionally change between green and orange. If this occurs
then it is recommended to use the phase reference transformer. If the instrument is being
used in Single Phase mode it will only attempt to detect the phase reference on channel 1,
but if it is being used in three phase mode all three input channels will be attempted. This
information is logged in the capture reports and can be viewed at the end of the data capture
process.
CableData Collector Operating Manual
Page 11 of 54
1365/L/01/1
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