Handheld turns ratio tester TRT-H is DV Power single-phase instrument specially designed for measuring transformer turns ratio of single-phase and three-phase transformers.
Together with the turns ratio, the instrument also measures excitation current and phase angle. By measuring these two parameters, it is possible to detect failures, related to transformer core or windings, that cannot be spotted by measuring only the turns ratio.
The transformer turns ratio is determined by applying AC voltage across high voltage winding, accurately measuring AC voltage across the corresponding unloaded transformer winding, and then displaying the ratio of these voltages. A user can enter a transformer’s nameplate voltages, so that turns ratio deviation can be calculated. This feature eliminates any error otherwise caused by an operator’s manual calculation. TRT-H compares the measured turns ratio with the nameplate ratio and prints out the % of error for each test.
The instrument can output a maximum test voltage of 40 V AC for testing the turns ratio of distribution transformers, but it can also generate a very low voltage of 1 V AC which is necessary for the turns ratio verification of most current transformers. By measuring the phase angle, the polarity of instrument transformers can be checked.
The list of instrument applications includes:
TRT-H is powered by an internal Li-Ion battery. Up to 100 tests can be performed with a fully charged battery. The battery charging time is 2.5 hours.