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Three-Phase Transformer Turns Ratio Tester

TTR300 series

  • TTR300 series
  • Overview  
  • Downloads  
  • Stand-alone or remote-control operation
  • Accurately measures ratio, phase deviation and excitation current
  • Field upgradeable without compromise to calibration
  • Built-in capability for storing and downloading test results in an XML format, via RS-232, Ethernet or USB ports (depending on model)
  • Highest ratio measurement (45,000:1); highest accuracy (0.1%)

The TTR300 Series of three-phase transformer turns ratio test sets are designed to measure the turns ratio of power, instrument, and distribution transformers in a substation or manufacturing environment. The instruments are ideal for use by power transformer manufacturers. Their unique testing procedures and storage capability allows an operator to set up and test difficult three-phase transformers in a fraction of the time than it used to take with other TTRs.

The TTR300 Series also measure the phase deviation of the transformer primary versus secondary. This quickly indicates problems such as partial shorted turns and core faults. This is also useful in verifying phase errors in all types of PTs and CTs.

Each unit comes equipped with a remote-control switch for single person testing. This allows the operator to test transformers with LTCs very quickly.

The Series consists of three instruments:


The TTR300 is designed to be completely remote controlled via a PC running PowerDB LITE (included) or PowerDB (full version) PC software applications. The TTR300 is field upgradeable to the TTR310, TTR320 or TTR330.


The TTR310 has the ability to store test results, upload results to a PC (via RS232 serial port), and/or print them in the field via optional thermal paper printer, without the use of an external computer. Please note: The TTR310 is a direct replacement for the three-phase TTR, C/N 550503


The TTR330 offers a new user interface which allows the operator to interact with the PowerDB ONBOARD software system via full QWERTY and navigation keypads as displayed on an 8.4” VGA bright-color screen. An advanced feature of the TTR330 allows the user to customize test forms via optional full-version PowerDB.