Handheld transformer turns ratio tester (TTR)

  • Fully automatic, handheld, fast, easy-to-use, robust, lightweight
  • Battery powered (AA or LR-6)
  • Tests turns ratio, excitation current, and polarity
  • Simple, one-button operation
  • Rugged metal connectors on leads and unit

The TTR25-1 handheld transformer turns ratio tester (TTR) is a robust, lightweight, and battery-operated instrument. It is used to measure the turns ratio, excitation current, and polarity of windings in single- and three-phase distribution and power transformers (tested phase-by-phase), as well as potential and current transformers (PTs and CTs), and tapped transformers. Deviations in these measurements will quickly indicate problems in transformer windings or in the magnetic core circuits.

The unique design of the TTR25-1 allows you to operate the test set while holding it in one hand. It effectively eliminates you having to kneel or bend down to operate the instrument and speeds up testing time. Realising the variety of harsh environments in which the TTR25-1 must operate, special attention has been paid to making it extra rugged and robust, with a high impact, shock-resistant case. Yet it is also incredibly lightweight at a mere 870 g (1.9 lbs). Additionally, it features a high contrast, backlit LCD screen which can be seen in bright or ambient light.

This unit measures a high turns ratio of 20 000:1 accurately with the lowest excitation voltage. The excellent repeatability of the TTR25-1 helps you to determine the condition of transformers under test. It is designed for simple, one-button operation with the measured results displayed directly on the easy-to-read LCD screen, or printed to the optional printer.

The TTR25-1 is particularly suited for testing in substations, transformer manufacturing environments, and meter shops. This type of TTR is best suited for power transformers up to 1 MVA. It it used to determine the no-load accuracy of PTs and CTs and also determine the need to further test faulty PTs and CTs. The TTR25-1 applies voltage to the high voltage winding of a transformer and accurately measures the resulting voltage from the low voltage winding. The ratio of voltages is directly proportional to turns ratio. In addition, the unit measures excitation current and polarity, needs no additional software, and comes ready to use out of the box.

Technical Documents
Technical guide
A Guide to Transformer Ratio Measurements