Ct Example Connections; Ct Testing - AEMC 8500 User Manual

4.4 CT
4.4.1

CT Example Connections

Current Transformer (CT) ratio testing is performed by connecting the H
cable set to the X winding, and by shorting the X cable set through the
CT aperture, as depicted below. This creates a step-down configuration
in which the X winding serves as the primary circuit, and the X cable set
serves as a one-turn secondary winding.
4.4.2

CT Testing

1. When the instrument is set for CT testing, the DTR
Test Mode Selected message after the initial power-up sequence. This
message indicates that the DTR
2. Press the TEST button once to begin the test cycle.
3. The next message displayed is *Ratio Testing [TEST] to Cancel. The
asterisk ( * ) will blink as testing proceeds. Testing may be cancelled at
this time by pressing the TEST button once. If the test continues, Ratio
and Excitation current will be displayed.
4. Once test results are recorded, press the TEST button to reset for the
next test.
NOTE: There are certain low mass, low ratio CT's where the DTR
may not be able to provide the correct ratio. The error message will
be "High Excitation Current."
As in VT/PT Test Mode, this routine may be repeated as many times as
needed without powering down the unit. The CT Test Mode remains active
until the unit is powered down.
14
CURRENT TRANSFORMER
X2
X
BLACK
X
RED
Digital Transformer Ratiometer DTR
H
RED
H
BLACK
X1
is now ready to execute a test.
®
will display the CT
®
Model 8500
®
®