Vanguard EZCT - Manual (Page 2)

The EZCT is a microprocessor-based, current-transformer test set. This rugged
and portable test set can perform the current transformer (CT) excitation, CT
current-ratio, and winding polarity tests. Current transformers can be tested in
their field-mounted configuration, eliminating the need to remove bushings or
current transformers from the host equipment.
Excitation Test
The CT excitation test is performed using the ANSI/IEEE C57.13.1, IEC 60044-1 test
method. The EZCT applies an AC variable test voltage (up to 1,200 Vac) to the CT’s
secondary windings. The EZCT records and displays the test voltage and excitation
current applied to the current transformer during the excitation test. Once tests are
completed, up to 10 excitation curves and knee-point voltages of the tests can be
plotted on the built-in thermal printer. IEEE-30, IEEE-45, ANSI/IEC 60044-1
(10/50) knee point voltages are also calculated and printed on the test report.
CT Ratio and Polarity Tests
The EZCT determines the CT current-ratio using the ANSI/IEEE C57.12.90 meas-
urement method. A test voltage is applied on the CT’s X terminals and the induced
voltage is measured across the CT’s H1 and H2 terminals. The current-ratio is dis-
played on the screen and stored in memory. The current-ratio measuring range is
from 0.8 to 5,000. Winding polarity is displayed as a “+” sign (in-phase) or “-”
sign (out-of-phase) and is annotated with the phase angle in degrees.
Simplify
EZCT
TM
Current-Transformer Testing Made Easy
Current-Transformer Test Set
Ordering Information EZCT TM Current-Transformer Test Set
EZCT TM , Cable, Software Part No: EZCT
EZCT TM Shipping Case Part No: EZCT Case
4.5-inch Printer Paper Part No: Paper TP4
User Interface
The EZCT features a back-lit LCD screen (4 lines by 20 characters) that is view-
able in both bright sunlight and low-light levels. A rugged, alpha-numeric,
membrane keypad is used to enter test information and to control the unit’s
functions. The test voltage range (50V at 2A, 200V at 2A, 1,200V at 1.5A) is
selected with a switch on the control panel. A voltage control knob is used to
control the variable test voltage output.
Thermal Printer
A built-in 4.5-inch wide thermal printer can print the current transformer test
report and plot the excitation curves.
Internal Test Record Storage Capacity
The EZCT can store up to 128
current-transformer test records
in Flash EEPROM. Each test
record may contain up to 10
excitation curves, polarity, and
current-ratio test data sets.
Test records can be recalled
and printed on the built-in
thermal printer.
Computer Interface
The EZCT can be used as a
stand-alone unit or can be
computer-controlled via the
built-in RS-232C or USB inter-
faces. Windows
® XP/Vista-
based Current Transformer
Analysis software is provided
with each EZCT. This software
can be used to retrieve test
records from the EZCT and
can also be used to run CT
tests from the PC. Tabulated
test records can be exported in
Microsoft
® Excel format.