Megger TTRU3 True Three-Phase Transformer Turns Ratio Tester

Megger TTRU3 Overview

The Megger TTRU3 is a true three-phase transformer turns ratio (TTR) tester that connects to all three phases at once and performs a complete turns-ratio test in less than ten seconds. Rather than testing one phase at a time, it energises the transformer as it operates in service, giving faster, more representative results. It is the smallest and lightest three-phase test set on the market, yet delivers laboratory-grade accuracy from a bright 7-inch touchscreen.

The TTRU3 performs patent-pending three-phase step-up ratio tests as well as step-down TTR tests, with five-digit resolution. Megger guarantees ±0.05% ratio accuracy for step-up excitation at 25–250 V on ratios 0.8–200 (most power transformers) and for step-down excitation at 25–48 V on ratios 0.8–1000; lower excitation voltages and higher ratios carry wider tolerances (TTRU3 datasheet). It measures turns ratio, phase displacement (0–360°, ±0.05°) and excitation current, and can run automated on-load tap-changer (OLTC) test sequences. Mains powered with USB data export, it is designed for fast, repeatable testing of power and distribution transformers in substations and manufacturing.

Who the Megger TTRU3 is for

The Megger TTRU3 is for utility, OEM and service teams who need a true simultaneous three-phase turns-ratio test on power and distribution transformers, including delta LV, zigzag and phase-shifting units. It suits crews who want one three-phase lead-set connection, built-in OLTC control and laboratory-grade ratio accuracy in a portable touchscreen instrument.

MME is an authorized Megger representative in the UAE. Browse our power transformer testing and the Megger range. Verify or check the TTRU3 with the Megger TRS1. For winding resistance plus ratio in one analyser, see the Megger TAU3. Broader substation apps sit on the Megger TRAX 220.

Megger TTRU3 Key Features

What the Megger TTRU3 gives a transformer crew:

• Simultaneous three-phase TTR from one lead-set connection — a full test in under 10 seconds (Megger TTRU3).
• Patent-pending three-phase step-up excitation (and step-down) inducing up to 250 V on the primary to handle large transformers.
• Guaranteed ratio accuracy of ±0.05% from -20 °C to +50 °C at 25–250 V step-up (ratio 0.8–200) or 25–48 V step-down (ratio 0.8–1000); five-digit resolution.
• Measures turns ratio, phase displacement and excitation current.
• Automated on-load tap-changer (OLTC) test sequences.
• Bright 7-inch (180 mm) touchscreen; smallest and lightest 3-phase set on the market.
• Mains powered with USB data export and optional thermal printer.

Megger TTRU3 Applications

Where engineers use the Megger TTRU3:

• Fast three-phase turns-ratio testing of power and distribution transformers.
• On-load tap-changer testing with automated sequences.
• Commissioning, maintenance and manufacturing quality control.
• Phase-displacement and excitation-current diagnostics.

What comes with the Megger TTRU3

What a typical Megger TTRU3 kit includes:

• TTRU3 true three-phase turns ratio tester.
• Three-phase test lead sets and clips.
• Mains lead and USB drive.
• Transport case and user documentation.

Kit contents and version (Basic/Advanced) vary by order; contact MME to confirm your configuration.

Megger TTRU3 FAQ

What transformer crews ask about the TTRU3:

• Why true three-phase instead of per-phase? On delta LV windings, single-phase excitation can circulate current in the delta and degrade accuracy; simultaneous three-phase excitation balances flux and speeds the job.
• Step-up or step-down by default? In auto mode Megger uses step-up (excite LV/tertiary, measure HV) after a low-voltage safety/connection check.
• How often should it be checked? Megger recommends a full performance check at least yearly; the optional TRS1 ratio standard supports field verification.
• Can it handle OLTCs? Yes. Built-in OLTC control runs automated tap sequences so every tap can be measured without reconnecting.

Why buy from MME in UAE

MOHAMMAD MAHDI Electronics Trading LLC (MME) is an authorized Megger representative across the UAE and the wider Gulf region. We offer competitive pricing, expert application support and reliable after-sales service to keep your transformer testing programme running smoothly.

Download the Megger TTRU3 datasheet