Eaglotest is pleased to introduce the S456 PRO Turns Ratio Tester, developed for fast and efficient transformer testing during commissioning, routine inspection, preventive maintenance, condition assessment, and troubleshooting.
The S456 PRO measures turns ratio, ratio error, excitation current, phase angle, vector group, polarity, and tap position through a streamlined test workflow. Its simultaneous three-phase excitation design allows technicians to assess all three phases efficiently, reducing repetitive connections and improving on-site testing productivity.
With a turns ratio measurement range of 0.8000 to 10,000 and a best accuracy of ±(0.1% of reading + 3 digits), the S456 PRO supports a wide range of transformer applications. It also measures excitation current from 0.01 mA to 1000 mA and phase angle from 0.0° to 360.0°, providing additional diagnostic references for evaluating winding consistency, core magnetisation behaviour, wiring relationships, and tap-changer condition.
Four selectable test voltages—4 V, 10 V, 40 V, and 90 V AC—allow users to adapt the test conditions to different transformer types and measurement requirements. The instrument uses a three-phase sinusoidal inverter output with automatic voltage regulation, soft-start and soft-stop operation, HV/LV reverse-connection protection, and output short-circuit protection.
For tap-changer testing, technicians can carry out consecutive measurements across different tap positions using the instrument’s continued-testing workflow. When operated through the S456 PRO TTR PC software, individual tap measurements can be consolidated into the same test session for tap-by-tap review, comparison, analysis, and reporting.
The S456 PRO integrates with the S456 PRO TTR PC software for test control, data management, analysis, and report generation. Users can configure test parameters, monitor live measurements, import records from the instrument, review complete tap-test sessions, and export structured reports in PDF or Excel format. This reduces manual data entry and supports consistent record keeping for historical comparison and maintenance planning.
The S456 PRO supports testing of:
Three-phase and single-phase power transformers
Potential transformers and voltage transformers (PT/VT)
Current transformers (CT)
Zigzag and Z-type transformers
Transformer vector group and polarity
Designed for professional field use, the S456 PRO features a 5.6-inch touchscreen, a built-in rechargeable lithium battery, storage for up to 500 test records, Bluetooth connectivity, USB data transfer, and an IP54-rated enclosure. Its electrical safety design has been developed with reference to the requirements of IEC 61010-1.
The S456 PRO expands Eaglotest’s transformer testing portfolio with a practical solution for utilities, industrial facilities, transformer manufacturers, service contractors, and maintenance teams requiring efficient testing, straightforward operation, and dependable test documentation.
The Eaglotest S456 PRO Turns Ratio Tester is now available for distributor enquiries, product demonstrations, and evaluation.
