AVTMTTR25 Rev C April 2008
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INTRODUCTION
About the TTR25
The TTR25 Handheld TTR
®
Test Set is a fully automatic, self-checking, self-
calibrating unit. The test set measures the turn ratio, excitation current, and
phase displacement (polarity) of single- and three-phase (phase by phase)
distribution transformers, as well as power, potential and current transformers.
The TTR25 Handheld TTR
®
Test Set is powered by six AA-size replaceable
alkaline batteries. The test set is a portable instrument housed in a sturdy plastic
case. A carrying case with strap and an accessory pouch is provided with the test
set.
The test set can be used to test single-phase and three-phase transformers, both
with and without taps in accordance with the requirements of the IEEE C57.12.90
– 1997 standards. For three-phase transformers, the test set is connected to
each of the three phases of the transformer to be tested, and measurements are
made on a phase by phase basis.
Turn ratio, phase displacement (polarity), and excitation current are displayed on
a large LCD. Transformer excitation current helps to detect transformer shorted
turns or an unequal number of turns connected in parallel. Operating condition
(error) messages identify incorrect test connections, abnormal operating
condition, or winding problems. Test results can be printed out on an optional
printer.
Features include:
Fully automatic operation.
Self-checking at power-up.
Self-calibration at each measurement.
User-friendly, one button operation.
Test turn ratio, excitation current, and phase displacement (polarity).
