©Measurlogic
Page 12
MQ0051-20F
7334 S. Alton Way, Centennial CO 80112
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web: www.measurlogic.com
A
B
C
Load 1
A
B
C
Load 2
3.3.3
Connecting the CTs from Multiple Loads to the Screw Terminals
The DTS SMX allows for ease and flexibility when monitoring multiple branches as a
Total Load
. The DTS SMX
allows multiple CT sensors to be connected in parallel via the screw terminals.
When using parallel CT sensors, the following guidelines must be followed to ensure accurate measuring.
•
All CT sensors
must have a 333mV output
. (Rogowski CTs cannot be connected in parallel.)
•
All CT sensors must be of the
same manufacturer/model number and current rating
.
•
A full set of CT sensors must be used for each load.
•
The pair of wires from the CT sensor to the screw terminal must be twisted.
•
All CT sensors must be terminated at the screw terminal.
•
A maximum of 3 loads can be monitored at once (Contact Measurlogic if more than 3 loads must be
monitored).
•
The measured phase current will be the total current across all the loads on that phase.
•
The CT primary rating for the DTS SMX must be set to the
CT rating * Number of CT sets.
•
The example below shows how to calculate the service current for figure 3.1.1.
Service Current for Figure 3.1.1
Number of CT Sensor Sets
2
CT Rating
100 Amps
CT Primary
200 Amps
A
N
B
C
Load 1