Megger TTR20 - 1 Introduction; About the TTR20 (TTR20-1)

AVTMTTR20 Rev 4 Dec 2015
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INTRODUCTION
About the TTR20 (TTR20-1)
The TTR20 and TTR20-1 Handheld TTR
®
Test Sets are fully automatic, self-
checking, self-calibrating units. The TTR20-1 has metal lead connections versus
plastic for the TTR20 (Replaced with the TTR20-1). This manual still refers to the
TTR20 as a general model number, but for purposes of new instruments, only
the TTR20-1 is currently sold.
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 TTR20 Handheld TTR
®
Test Set is powered by six AA-size replaceable alkaline batteries.
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
– 2013 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).
 Easy measuring of single and three phase (phase by phase) transformers, as
well as potential & current transformers.
 Checking reverse test lead or winding connections at start of each test.