Theory Of Operation; A.a.b Theory Of Operation - Raytech TR-MARK III Instruction Manual

A.A.B Theory of Operation

Circuitry Design:
The T-Rex system generates three (3) perfect sine waves from DC coupled ± 24 Volts. The
incorporation of D/A converters with the proper amplification produces an AC sine wave on
three (3) output channels. These sine waves are produced with identical amplitudes and are
shifted in phase 120° . The T-Rex is basically an artificial 3 phase generator.
All system measurements are conducted in the appropriate ratio meter connected to the T-
Rex. No measurements are conducted by the T-Rex. Standard ratio meter measurements
can be made directly through the T-Rex without any influence.
Design Consideration:
The T-Rex system was designed to be used world wide with consideration to test engineers
utilizing various specifications. Nomenclature and operation of the T-Rex was decided upon
with that consideration.
It also was designed to assist the engineer in making precise phase angle measurements.
The T-Rex measurements will indicate phase angles of ± 180° .
The measured result indicates to the engineer that the phase relationship is in a clockwise or
counter clockwise direction. With this indication the engineer is able to adjust the vector
grouping number to correspond to the closest relationship in 30 degree increments. This is
done to allow for greater accuracy of the phase relationship measurement.
For example:
Measurement of a transformer with a phase angle of 42 degrees. The first step is to select
and measure with a vector group 0 on the ratio meter. That would indicate that there is no
phase angle displacement from the primary to the secondary windings.
The T-Rex would then measure and indicate an angular displacement of +42° .
The engineer would then correct the reading by adjusting the vector phase group selection to
a 1 (indicating +30° shift). The resultant reading from the T-Rex would be +12.0° with a more
accurate result.
Rotation convention and nomenclature:
All systems dispatched prior to May 2002 are sent with the following convention:
When transformer type 3P:3P-0 is chosen:
A Transformer with the following configuration D-Y 1 would have a (+) Positive 30 º result.
And likewise, a transformer with a configuration of D-Y 11 would have a (-) Negative 30 º
result.
90100.1.02 Instruction Manual TR-MARK III Page 56 of 70