- Fully automatic knee point detection
- Ratio range of 0.9 to 15,000
- 5 low side tap connections
- Performs CT excitation, current ratio, and polarity tests on current transformers
- Manual or automatic degauss and measurements
- Easy, one-time hook up for up to 5 CT taps
- Automatic test voltage range with adjustable limits
- Easy to use tap selector interface
- Data storage of more than 10,000 measurements
- Color 5.7″ LCD touch screen display for easy operation
- 3″ graphic-capable printer
- Two USB interfaces and one RS-232 serial port
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. The EZCT is capable of outputting 50 Vac at 2A and 200 Vac at 2A.
The EZCT-10 has all the features of the EZCT, but uses a heavy-duty transformer to perform the CT excitation test. It is capable of outputting 50 Vac at 10A and 200 Vac at 10A.
CT 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 measurement 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 displayed 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.