• Highest ratio: 0.8 - 15,000
• Built-in 4.5" thermal printer
• Excitation current measuring
• Phase angle measuring
• Computer interface
• Name-plate turns ratio calculation
• Computed % error based on measured and calculated ratio
• Automated phase switching

The ATRT-03 is a three-phase, transformer turns-ratio tester. The Model ATRT-03 is lightweight, rugged, and portable, and is designed for transformer testing at utility power substations.

The Model ATRT-03/03A determines the transformer turns ratio by accurately measuring the voltages across the unloaded transformer windings and then displaying the ratio of these voltages (ratios range from 0.8 to 15,000). The ATRT-03A calibrates each measurement to ensure the turns-ratio accuracy.

The ATRT-03 can perform a specifi c test for each transformer

type (such as single phase, delta to Y, Y to delta,

delta to delta, or Y to Y) without the need to switch test

hookup cables. Also, the unit’s automatic transformer

phase detection feature can detect different transformer

vector diagrams. The ATRT-03 can automatically detect

and test 67 transformer types defi ned by ANSI, CEI/IEC

and Australian standards.

To prevent an accidental wrong test-lead hook-up (e.g.,

when the operator reverses H and X leads), the ATRT-03

outputs a low-level test voltage to verify the hook-up

condition before applying the full test voltage to the

transformer.

In addition to measuring a transformer’s turns-ratio, the

ATRT-03 can also measure a transformer’s excitation

current (in milli-amperes) and its winding phase angle.

Three test voltages (8 Vac, 40 Vac, 100 Vac) allow the

ATRT-03 to test CT’s and PT’s, as well as power transformers.

The ATRT-03 can also calculate the turns-ratio percentage

error if the transformer’s nameplate voltages are

provided. The baseline turns-ratio is calculated using the

nameplate voltages, and the test results are compared

to the baseline turns-ratio. The percentage error is then

calculated from the difference between the baseline and

test turns-ratios.

User Interface

The ATRT-03 features a back-lit LCD screen (20

characters by 4 lines) that is viewable in both

bright sunlight and low-light levels. The test

results screen displays the transformer turnsratio,

excitation current, and turns-ratio accuracy.

The unit is controlled via a rugged, 16-key,

membrane keypad.

Transformer Test Plans

The ATRT-03 can store up to 128 transformer

test-plans in its Flash EEPROM. A test plan is

comprised of the transformer nameplate voltages

for each tap setting. The calculated turnsratio

based on the nameplate voltages is compared

with the measured turns-ratio to derive

the percentage error and Pass/Fail results. By

using a test plan, a transformer can be quickly

tested and turns-ratio Pass/Fail reports can be

reviewed. Test plans can be created with the

included PC software and can be transferred to

the ATRT-03 via the RS-232C interface.

Internal Test Record Storage

Up to 200 test records can be stored in the

ATRT-03’s Flash EEPROM memory. Each test

record may contain up to 99 turns-ratio, excitation

current, phase angle, and nameplate voltage

readings. Test records can be recalled locally

or transferred to a PC via the RS-232C interface.

Computer Interface

The ATRT-03 can be computer-controlled via

the RS-232C interface using the supplied PC

software. The Windows®-based software can

be used to run a test and to store test results on

a PC. Test results can also be exported to Excel,

PDF, and XML formats for further analysis.

Transformer Load Tap Changer Control

Voltage regulator or LTC tap positions can

be changed remotely using the optional Tap-

Changer Remote Control Box. This option eliminates

the need to manually raise or lower tap

positions from the transformer control panel.

Built-in Thermal Printer

The ATRT-03 features a convenient built-in 4.5-

inch wide thermal printer that can be used to

print test results.

ordering information

Part number ATRT-03 ATRT-03, cables, and PC software

Part number ATRT-03 CASE ATRT-03 shipping case

Part number Paper-TP4 Thermal printer paper