Megger TTRU3 Three-Phase Transformer Turns Ratio Tester | Simultaneous three-phase excitation, step-up measurement up to 250 V, ±0.05%, 7-inch touchscreen

Megger TTRU3 Three-Phase Transformer Turns Ratio Tester: Simultaneous Three-Phase Excitation

Overview

The TTRU3 is a Megger three-phase transformer turns ratio tester that measures using three-phase step-up excitation (patented by the manufacturer). With one set of three-phase test leads connected once, a three-phase test is completed within 10 seconds, and it can also measure phase-shifting transformers and zig-zag transformers. Accuracy is guaranteed over −20 to 50 °C.

Key Specifications

• Measurement modes: Three-phase step-up, three-phase step-down, single-phase step-up, single-phase step-down
• Ratio range and accuracy: Step-down 25–48 V: 0.8–1000 ±0.05%, up to 2000 ±0.10%, up to 15000 ±0.30%, up to 50000 ±1%; step-up 25–250 V: 0.8–200 ±0.05%
• Output: Three-phase 1–48 V AC, up to 250 V induced on the primary side; 50–480 Hz; 0.1 mA–1 A
• Other measurements: Excitation current ±1% ±0.1 mA; phase 0–360°, ±0.05°; polarity; automatic vector group detection
• Model differences: TTRU3-ADV max. induced 125 V, step-up ratio up to 100; TTRU3-PRO/EXP 250 V, step-up ratio up to 200
• Display and data: 7-inch touchscreen (1100 nits); stores 2000 three-phase results; USB export to XLS/PDF; optional 2-inch printer
• Standards: IEC 61010-1; IEEE C57.152-2013, IEC 60076-1:2011
• Dimensions, weight and protection: 406 × 304 × 254 mm, 6.5 kg; IP51 (IP67 when stowed in the transport case)

Applications

• Ratio and polarity acceptance testing of power and distribution transformers and CTs/PTs.
• Ratio testing at each tap position of on-load tap changers (OLTC).

Specifications per the Megger product page and TTRU3 datasheet (V08) (retrieved 2026-10-21).