Chapter 3—Installation and Wiring
30
Power Xpert C445 Global Motor Management Relay
MN042003EN—January 2019
www.eaton.com
Using External Current Transformers
Customer Supplied CTs
Other external CTs may be used with C445. For best
accuracy, provide CTs with at minimum the following ratings/
features. Customers are responsible for ensuring that the
environmental and regulatory ratings of their selected CTs
meet the requirements of their application.
Recommended CT Specifications:
Insulation Voltage
: Equal to or above Voltage of application
Insulation Rating
: 10kV BIL Full Wave <OR>
Test Voltage One Minute 3kV
Rated secondary current
: 5A or 1A
Frequency
: 50/60 Hz
Accuracy
: 0.3 % or better
Note:
Systems using external measurement CTs with a
5A secondary current or XCT_ _ _-5 should use the
C445MA-005_. Systems with CTs that have a
1A secondary current should use the C445MA-2P4_
measurement module.
External CT Wiring Instructions
1.
Pass primary motor lead through opening in CT in proper
direction. Perform for each phase.
●
Eaton XCT_CTs: Pass through in direction
H1
R
H2
●
Customer Supplied CTs: Follow manufacturer’s
directions
2.
Attach wire to secondary output terminal on external CT
and pass through C445MA-005_ in proper direction (in
through
1/L1, 3/L2, 5/L3
terminals). Perform for each
phase.
●
Eaton XCT_CTs: Start from terminal X1
●
Customer Supplied CTs: Follow manufacturer’s
directions
3.
Secure wire after measurement module pass through
into second terminal on external CT. Perform for each
phase.
●
Eaton XCT_CTs: Secure in second, unmarked terminal
●
Customer Supplied CTs: Follow manufacturer’s
directions
Table 8. External CT Settings
When using external CTs, CT ratio must be set in the C445 using the following parameters:
Parameter
Units
Increment
Minimum
Maximum
Default
Modbus Register
CT Ratio—Primary
Amps
1
1
1
918
CT Ratio—Secondary
Amps
1
1
1
919