90 / 162
90
Current Transformers
F
3500 Scarlet Oak Blvd. St. Louis MO USA 63122 V: 636-343-8518 F: 636-343-5119
Web:
http://www.crmagnetics.comE-mail:
sales@crmagnetics.comThe Professional
Energy Monitoring
Company
ISO 9001:2008QualityManagementSystem
M N TI
X2
Black X1
White
H1
This illustration shows the internal construction of a current trans-
former. The outside face of the transformer is identified as H1.
The opposite face is identified as H2. The secondary leads are
identified as X1 and X2.
Current flowing out of terminal X1 will have the same polarity as
current flowing into terminal H1.
The current transformer window opening should be sized accord-
ing to the outside diameter of the wire and the number of wires,
with ample clearance added to facilitate installation.
Use the below formula for multiple wires of the same diameters
through the current transformer window opening.
Minimum Window
Diameter
Outside Wire
Diameter
K x
=
Number of
Wires Through
Opening
2
3
4
5
6
7
8
9
K
2
2.165
2.414
2.704
3.0
3.0
3.73
3.83
Window Openings
Winding Polarity
Typical Applications