3300 ACM Installation and Operation Manual Power Measurement Ltd.
3-10 General Operation
3.5 SELECTING DIRECT OR PT INPUT &
SETTING PT SCALES, AMPS SCALE,
VOLTS MODE
This section details the minimum basic programming setup
required for proper operation of the 3300 ACM.
Direct Connection or Using PTs
The setting of the phase voltage input parameters is depen-
dent on the voltage of the system being monitored and
whether the 3300 ACM is being connected directly to the
lines, or if PTs (potential transformers) are being used.
WARNING
PTs are required for connection to all Delta
systems.
DIRECT CONNECTION
The basic model 3300 ACM supports direct connection to
Wye systems up to 347/600 VAC and Single Phase systems
up to 347/694 VAC without the need for PTs.
For direct connection, the USING PTS? parameter of the 3300
ACM must be set to NO. The 3300 ACM will automatically
select the correct scaling.
PT CONNECTION
PTs must be used for Wye systems above 347/600 VAC,
Single Phase systems above 347/694 VAC, and for all Delta
systems.
If PTs are used, set USING PTS? to YES. The following two
parameters which appear will then be PT PRIMARY and PT
SECONDARY. These are used to tell the 3300 ACM what the
PT voltage ratings are, allowing the 3300 ACM to set its
internal full scale input references.
Set PT PRIMARY to the primary rating of the PTs used. This
should normally be equivalent to the full scale line levels
which are being measured by the meter. For example, for a
13.8 kV system, 120:1 ratio PTs with primary ratings of 14.4
kV are typically used. For these PTs, set the PT PRIMARY to
14400.
Set PT SECONDARY to the secondary rating of the PTs used.
The maximum secondary voltage allowable is 347 VAC.
USING THE HIACC OPTION
The HIACC (high accuracy) option of the 3300 ACM provides
a preset input voltage scale of 120, 277 or 347 VAC. To ensure
optimum accuracy when using a 3300 ACM with this option
installed, direct connect only to systems with full scale levels
equivalent to the specified 3300 ACM input voltage. For
example, a 277 VAC HIACC meter should only be used with
a 277 VAC system.
If PTs are used with the HIACC option, always use PTs
with secondary voltages equal to the specified 3300 ACM
input voltage, and set the PT SECONDARY parameter to
that value.
Amps Scale
The basic model 3300 ACM provides 5 Amp phase current
inputs. If the CTs used are rated for a 5 Amp full scale
output, set the AMPS SCALE should be set to the primary
rating of the CTs being used.
The 3300 ACM also offers a 1AMP option which for use with
CTs with 1 Amp full scale output.
If the CTs are not rated for a 5 Amp or 1 Amp full scale
output, contact Power Measurement or your local representa-
tive for more information.
NOTE
For the above parameter settings,
PT PRIMARY x AMPS SCALE
should be less than 999,999,999 for correct
display of kW, kVAR, and kVA readings
which have a maximum range of 999,999.
Volts Mode
The VOLTS MODE should be set according to the system
connection configuration (4-WIRE WYE, 3-WIRE WYE, 3-
WIRE DELTA, SINGLE PHASE). Refer to Chapter 2 for more
information.
The 3300 ACM also offers a demonstration mode which will
generate dynamic readings for all real-time measurements
based on the input scales programmed by the user. These
readings can be viewed from the front panel or via communi-
cations. To use this feature, set VOLTS MODE to DEMO.
Courtesy of NationalSwitchgear.com
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