Transformer Turns Ratio Testers (TTR)

Technical documentation

Download HVEX Standalone Transformer Turns Ratio Tester datasheet (English, PDF)

Download HVEX Combined Winding Resistance and TTR Tester datasheet (English, PDF)

Request a QuoteTransformer turns ratio, phase displacement, and polarity testing. Atlas Energy supplies HVEX instruments for factory, commissioning, and maintenance tests on power, distribution, and instrument transformers. Choose a compact battery-powered TTR set or a combined instrument that also measures DC winding resistance.

Portable battery-powered TTR

The portable HVEX system measures turns ratio, phase angle, polarity, and excitation current. Automatic three-phase measurements support evaluation of ratio error, phase displacement, and tap information.

• Turns-ratio measurement range: 0.8–10,000.

• Published ratio accuracy: 0.1% from 0.9–200; 0.2% from 200–2,000; 0.3% from 2,000–10,000.

• Published voltage accuracy: 0.05% on the HV side and 0.1% on the LV side.

• Published phase-angle accuracy: 0.1°.

• Internal battery; charger input: 100–240 V AC.

• Dimensions: 320 × 240 × 130 mm (approximately 12.6 × 9.4 × 5.1 in).

• Weight: 3 kg (approximately 6.6 lb).

Combined TTR and inductive winding-resistance instrument

This separate HVEX configuration combines ratio testing with resistance measurement for highly inductive windings. A touchscreen, proprietary software, and Ethernet connection support local and remote operation.

• Supply: 110 V or 220 V, 60 Hz.

• TTR test output: 220 V; documented voltage ratio: 200.

• TTR uncertainty: typically 0.2%, maximum 0.5%.

• Winding resistance, high-resistance range: 1 Ω–5 kΩ, using 250 mA and up to 130 V.

• Winding resistance, low-resistance range: 100 µΩ–1 Ω, using 20 A and up to 2.5 V.

• Winding-resistance uncertainty: typically 0.2%, maximum 1%.

• Typical ramp time: 30 seconds for distribution-transformer winding-resistance tests; actual time depends on the specimen.

• Weight: 20.2 kg (approximately 44.5 lb).

Applications and selection

Ratio, phase, and polarity measurements help identify incorrect connections, tap discrepancies, and abnormal winding behavior. The combined instrument adds DC winding-resistance data for a broader transformer assessment. Compare results with the transformer ratings, configuration, and applicable test criteria.

HVEX documentation references ABNT NBR 5356/5440 and IEC 60076; the portable TTR product page also references IEC 61869 and IEC 61010-1. Contact Atlas Energy with the transformer type, ratio range, required measurements, and available supply to select the appropriate HVEX model. The specifications above apply to their respective configurations.