Part Number(s)

9023-UC [ATRT-01 S3]

The ATRT-01 S3 is Vanguard’s fourth generation, micro-processor based, single phase, automatic transformer turns-ratio tester. The ATRT-01 S3 uses the measuring method to determine the transformer turns-ratio. The transformer turns-ratio is determined by precisely measuring the voltages across the unloaded transformer windings. The ATRT-01 S3’s measuring circuitry self adjusts before each measurement to ensure turns-ratio accuracy. Two selectable test voltages, 4Vac and 40Vac, offer flexibility in testing different types of transformers.

• Standalone or computer-controlled
• Inexpensive
• Displays turns-ratio from 0.8-15,000
• Calculates turns-ratio percentage error
• Displays winding polarity and phase angle
• Displays excitation current

Part Number(s)

9036-UC [ATRT-01B S3]

The ATRT-01B S3 is Vanguard’s fourth generation, micro-processor based, single phase, automatic transformer turns-ratio tester. The ATRT-01B S3 uses the measuring method to determine the transformer turns-ratio. The transformer turns-ratio is determined by precisely measuring the voltages across the unloaded transformer windings. The ATRT-01B S3’s measuring circuitry self adjusts before each measurement to ensure turns-ratio accuracy. Two selectable test voltages, 4Vac and 40Vac, offer flexibility in testing different types of transformers.

• Standalone or computer-controlled
• Inexpensive
• Displays turns-ratio from 0.8-15,000
• Calculates turns-ratio percentage error
• Displays winding polarity and phase angle
• Displays excitation current
• Battery or AC-Powered

Part Number(s)

9037-UC [110V ATRT-03]
9038-UC [220V ATRT-03]

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.

• 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

Part Number(s)

9003-UC [ATRT-03 S2]
9003-PR [Printer Option]

The Vanguard Instruments ATRT-03 S2 is the third generation, microprocessor-based, automatic, three phase, transformer turns-ratio tester. This light weight, rugged, portable unit is designed for transformer testing at utility power substations.

• Highest ratio: 0.8 - 15,000
• Capable of detecting 130 different 3-phase transformer types defined by
• 3 Test voltages available: 8Vac, 40Vac, 100Vac
• Phase angle and excitation current measuring
• Computer Interface (RS-232C and USB Port)
• USB flash drive interface
• Name-plate turns ratio calculation
• Computed % error based on measured and calculated ratio
• Optional 4.5" thermal printer
• Powered from a single phase 100-264 Vac 50/60 Hz

Part Number(s)

9042-UC [ATRT-03A S2]

The Vanguard Instruments Company Model ATRT-03A Series 2 is Vanguard's third generation, microprocessor-based, automatic, three phase transformer turns-ratio tester.

The ATRT-03A Series 2 determines the transformer turns ratio using the measurement method. The ATRT-03A Series 2 generates and outputs an excitation voltage to the three transformer primary winding. The included secondary voltage is sensed and the transformer turns ratio is calculated.

• Capable of detecting 130 different 3-phase transformer types defined by plus phase shifting transformers
• Store up to 128 transformer test-plans in Flash EEPROM
• Store up to 112 test records in Flash EEPROM
• Built-in USB Flash Drive Interface
• Computer Interface (RS-232C and USB Port)
• 4.5 Inch thermal printer
• Built-in transformer load tap changer
• Powered from the built-in rechargeable lead acid batteries (3 hours) or a single phase 100-240 Vac 50/60 Hz.

Part Number(s)

9025-UC [CVT-765]

The Vanguard CVT-765 is a microprocessor-based, single phase, automatic, transformer turns-ratio tester. This portable test unit is specifically designed to measure the turns-ratios of Voltage Transformers (VT’s), Potential Transformers (PT’s), and Capacitor Voltage Transformers (CVT’s).

• Standalone or computer-controlled
• Can test CVT's rated up to 765 KV
• Displays turns-ratios from 75-15,000
• Calculates turns-ratio percentage error when nameplate voltages are provided

Part Number(s)

9105-UC [TRF-250]
9105-PR [TRF-250 built-in thermal printer option]
9105-SC [TRF-250 shipping case]

The TRF-250 is Vanguard's fourth generation transformer turns ratio tester. This latest design provides a higher turns-ratio test voltage of 250Vac, provides a wireless Bluetooth PC interface, and features a 44-key "QWERTY"-style membrane keyboard. All these features greatly improve the accuracy of the turns ratio readings, ease of operation, and reliability.

• Ratio Range: 0.8 - 50,000 to 1
• Capable of detecting 130 different 3-phase transformer types defined by
• 4 test voltages: 4Vac, 40Vac, 100Vac, and 250Vac
• Phase angle and excitation current measurement
• Bluetooth and USB PC interfaces
• 4.5-inch wide thermal printer (optional)

Part Number(s)

9008-UC [Tri-Phase]

Vanguard’s new TRI-PHASE is a true 3-phase transformer turns ratio tester designed to conform to the measurement method. The TRI-PHASE outputs a 3-phase excitation test voltage to the three transformer primary windings. The induced 3-phase secondary voltages are sensed and the transformer turns ratio is calculated. The TRI-PHASE is capable of measuring turns ratios from 0.8 to 15,000. The 3-phase excitation current, phase angle readings along with the turns ratios are displayed on the built-in LCD.

• Generates its own 3-phase transformer test voltage from single-phase AC or DC Power input
• Capable of detecting 130 different 3-phase transformer types defined by plus phase shifting transformers
• 64 x 128 graphic LCD screen
• Store up to 128 transformer test-plans in Flash EEPROM
• Store up to 112 test records in Flash EEPROM
• Built-in USB Flash Drive Interface
• Computer Interface (RS-232C and USB Port)
• 4.5 Inch thermal printer
• Built-in transformer load tap changer
• Powered from a single phase 100-264 Vac 50/60 Hz