Megger TTR310 - Description; Principle of Operation

AVTMTTR310 Rev 8 May 2016
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Description
Principle of Operation
The TTR310 test set provides accurate measurements of transformer input and
output voltages and the, calculates a transformer turn ratio. The TTR310 also
measures phase shift between primary and secondary windings of a transformer
and transformer excitation current.
A block diagram of the TTR310 test set is shown in Figure 4-1. The excitation
voltage transformer converts the main voltage into the test excitation voltage of a
transformer. The excitation voltage transformer outputs three test voltages: 80 V,
40 V, and 8 V. The transformer under test excitation current is measured by the
excitation current measurement circuitry. The test excitation voltage is applied to
a transformer under test through the H winding lead select circuitry. This
circuitry automatically excites the transformer windings depending on winding
connections. The same excitation voltage is applied to the reference conditioning
circuitry.
The transformer under test output voltage is connected to the X winding lead
select circuitry. This circuitry automatically connects the transformer winding
being tested to the range conditioning circuitry.