Vanguard EZCT-2000 User Manual download pdf (Page 6)

EZCT-2000 USER’S MANUAL REV 3

1.0 INTRODUCTION

1.1 General Description and Features

The EZCT-2000 is Vanguard’s second-generation microprocessor-based current transformer test

set. The EZCT-2000 can perform the current transformer (CT) excitation test, measure the CT

winding resistance and CT current-ratio automatically. All of the EZCT-2000’s test leads can be

connected to the CT output terminals (X1, X2, X3, X4 and X5), eliminating the need for lead

switching during testing. Test voltage output is automatically raised and lowered by the EZCT-

2000 without any operator intervention. With up to 2000 Vac excitation test voltage available,

the EZCT-2000 can easily perform excitation tests on very large CT’s.

Excitation Test

The CT excitation test is performed using the ANSI/IEEE C57.13.1, IEC 60044-1 test method. The

AC test voltage range for the CT excitation test (50 Vac, 300 Vac, 500 Vac, 1200 Vac or 2000

Vac) can be selected, and then the test voltage is raised and lowered automatically by the EZCT-

2000. The excitation test voltage and current data is collected and stored in the unit’s internal

memory. Any of the 10 possible combinations of X1 to X5 can be tested since all of the unit’s

test leads can be connected to all of the CT output terminals at the same time. Up to 10

excitation tests can be stored in one record. Once the test is completed, test results can be

printed and excitation curves can be plotted on the built-in 4.5-inch wide thermal printer.

CT Ratio and Polarity Test

The EZCT-2000 determines the CT current-ratio using the ANSI/IEEE C57.12.90 measurement

method. An AC test voltage is applied on any two terminals of the CT (X1 to X5), and the

induced voltage is measured through the CT’s H1 and H2 terminals. The CT current-ratio is

displayed on the screen and stored in memory. The current-ratio measuring range is from 0.8 to

5,000 to 1. The CT winding polarity is displayed as a “+” sign (in-phase) or a “-” sign (out-of-

phase) and is annotated with the phase angle in degrees.

CT Winding Resistance Test

The EZCT-2000 can also measure the DC resistance of the CT winding under test. The DC

winding resistance measuring range is from 100 micro-ohms to 10 ohms.

User Interface and Display

The EZCT-2000 features a back-lit LCD screen (4 lines by 20 characters) that is viewable in both

bright sunlight and low-light levels. A rugged, alpha-numeric, membrane keypad is used to

control the unit.

Built-in Thermal Printer

A built-in 4.5-inch wide thermal printer can print the current transformer test report and plot

the excitation curves.

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Vanguard EZCT-2000 User Manual Page 6