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.
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.
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.
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.
- TYPE – Portable current-transformer test set
- PHYSICAL SPECIFICATIONS – 16.8”W x 12.6”H x 12”D (42.7 cm x 32 cm x 26.9 cm); Weight: 55 lbs (25 Kg)
- INPUT POWER – 100 – 120 Vac or 200 – 240 Vac (factory pre-set), 50/60 Hz
- MEASUREMENT METHOD – ANSI/IEEE C57.12.90, IEC 60044-1 and ANSI/IEEE C57.13.1
- OUTPUT TEST VOLTAGES – 0–50Vac@2Amax;0–200Vac@2Amax;0–1200Vac@1.5Amax(5minon,10minoff)
- VOLTAGE READING RANGE – 0 – 1,250 Vac; Accuracy: ±1.0% of reading, ±0.5 volt
- CURRENT READING RANGE – 0 – 10A; Accuracy: ±1.0% of reading, ±0.01A
- CURRENT-RATIO RANGE – 0.8 – 99: ±0.5%, 100 – 999: ±1.0%, 1,000 – 5,000: ±2%
- PHASE ANGLE MEASUREMENT – 0 – 360 degrees; Accuracy: ±1.0 degree
- DISPLAY – Back-lit LCD Screen (20 characters by 4 lines); viewable in bright sunlight and low-light levels
- PRINTER – Built-in 4.5-inch wide thermal printer
- COMPUTER INTERFACES – One RS-232C port, One USB port
- INTERNAL TEST RECORD STORAGE – Stores 128 test records. Each test record may contain up to 10 excitation and ratio data sets
- INTERNAL TEST HEADER STORAGE – Stores 10 test header records
- SAFETY – Designed to meet UL 61010A-1 and CAN/CSA C22.2 No. 1010.1-92 standards
- ENVIRONMENT – Operating: -10 ̊ to 50 ̊ C (15 ̊F to +122 ̊ F); Storage: -30 ̊ C to 70 ̊ C (-22 ̊F to +158 ̊ F)
- HUMIDITY – 90% RH @ 40 ̊C (104 ̊F) non-condensing
- ALTITUDE – 2,000m (6,562 ft) to full safety specifications
- CABLES – One 20-foot X cable set, One 35-foot H cable set, power cord, One cable carrying duffel bag
- OPTIONS – Transportation case