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.

The TRF-250 determines the turns ratio of the transformer under test using the IEEE C57.12.90 measurement method. The turns-ratio range is from 0.8 to 50,000 to 1. Transformer turns ratio,  excitation current, and winding polarity are displayed on the built-in 128 x 64 pixels graphic LCD screen. The TRF-250 can be used as a standalone unit or can be computer-controlled.

• Ratio Range: 0.8 - 50,000 to 1
• Capable of detecting 130 different 3-phase transformer types defined by ANSI, IEC, and Australian standards
• 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)

TRF-250	Cables
Cable Part Number [8000-0005] USB Cable [ 6' (1.83m) ] 8000-0005 [8000-0009] H Single Phase Cable [ 15' (4.57m) ] 8000-0009 [8000-0010] H Extension Cable [ 25' (7.62m) ] 8000-0010 [8000-0011] X Single Phase Cable [ 15' (4.57m) ] 8000-0011 [8000-0012] X Extension Cable [ 25' (7.62m) ] 8000-0012 [8000-0013] H 3-Phase Cable [ 15' (4.57m) ] 8000-0013 [8000-0014] X 3-Phase Cable [ 15' (4.57m) ] 8000-0014 [8000-0015] LTC Control Cable [ 15' (4.57m) ] 8000-0015 [8000-0016] Power + Ground Combination Cable 8000-0016 [8000-0186] 3-Phase H Cable [ 30' (9.14m) ] 8000-0186 [8000-0187] 3-Phase X Cable [ 30' (9.14m) ] 8000-0187 [8000-0188] Single-Phase H Cable [ 30' (9.14m) ] 8000-0188 [8000-0189] Single-Phase X Cable [ 30' (9.14m) ] 8000-0189

TRF-250	Technical Specifications
TYPE Portable, lightweight, automatic 3-phase transformer turns-ratio meter PHYSICAL SPECIFICATIONS 18”W x 5”H x 12”D (45.7 cm x 12.7 cm x 30.5 cm ); Weight: 20 lbs (9.1 kg) OPERATING VOLTAGE 100 – 240 Vac, 50/60 Hz MEASUREMENT METHOD ANSI/IEEE C57.12.90 TURNS-RATIO MEASURING RANGE 0.8 – 50,000 to 1 TURNS-RATIO ACCURACY 0.8 – 1,999: ±0.1%, 2,000 – 3,999: ±0.25%, 4,000 – 14,999: ±1%, 15,000 – 50,000: ±2% @ 4 Vac 0.8 – 1,999: ±0.1%, 2,000 – 3,999: ±0.20%, 4,000 – 14,999: ±1%, 15,000 – 50,000: ±1.5% @ 40 Vac 0.8 – 1,999: ±0.1%, 2,000 – 3,999: ±0.20%. 4,000 – 14,999: ±1%, 15,000 – 50,000: ±1.5% @ 100 Vac 0.8 – 1,999: ±0.1%, 2,000 – 3,999: ±0.15%. 4,000 – 14,999: ±0.8%, 15,000 – 50,000: ±1.2% @ 250 Vac TEST VOLTAGES 4 Vac @ 1 Amp, 40 Vac @ 200 mA, 100 Vac @ 100 mA, 250 Vac @ 50 mA EXCITATION CURRENT READING RANGE 0 – 2 Amperes; Accuracy: ±0.1 mA, ±2% of reading (±1 mA) PHASE-ANGLE MEASUREMENT 0 – 360 degrees; Accuracy: ±0.2 degree ( ±1 digit) DISPLAY Back-lit LCD screen (128 x 64 pixels) viewable in bright sunlight and low-light levels PRINTER Optional built-in 4.5-inch wide thermal printer COMPUTER INTERFACES Bluetooth, USB port EXTERNAL DATA STORAGE One USB Flash drive interface port; Up to 999 transformer test records can be stored on a USB Flash drive (not included) INTERNAL TEST RECORD STORAGE Can store 112 transformer test records internally. Each record holds the test record header and up to 99 readings. INTERNAL TEST PLAN STORAGE Can store 128 transformer test plans internally. Test plans can be transferred to the unit from the PC via Bluetooth/USB port or via the USB Flash drive interface PC SOFTWARE Windows?-based Transformer Turns Ratio Analyzer application is included with purchase price LOAD TAP CHANGER CONTACT 240 Vac, 2 Amps SAFETY Designed to meet UL 61010A-1 and CAN/CSA C22.2 No. 1010.1-92 standards ENVIRONMENT Operating: -10? to 50? C (15? to +122? F); Storage: -30? C to 70? C (-22? to +158? F) CABLES One 15-foot (4.57m) single-phase set, one 15-foot (4.57m) 3-phase set, one 25-foot (7.62m) extension set, one safety ground, one USB, cable bag OPTIONS Transportation case WARRANTY One year on parts and labor Specifications are valid at nominal voltage and ambient temperature of +25?C (+77?F).