Raytech USA, Inc.
All rights reserved. No portion may be reproduced without written consent
6
THEORY OF OPERATION
Circuitry Design
The T-Rex system is designed to produce and generate 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 a smart artificial 3 phase
generator. This system is designed to handle loads with an impedance as low as 0.5 ohms.
All system measurements are conducted in the appropriate ratiometer connected to the T-Rex.
No measurements are conducted by the T-Rex. Standard ratiometer 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.
The T-Rex system was designed to assist the engineer in making precise phase angle measurements.
The T-Rex measurements will indicate phase angles of
180
.
The ratiometer, working in conjunction with the T-Rex, senses the phase rotation by
180
.
The measured result indicates to the engineer that the phase relationship is in a clockwise or
counterclockwise direction. With this indication the engineer is able to adjust the vector grouping
(Phase displacement) number on the ratiometer 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 shift of 42
.
Select and measure the transformer with a phase displacement (Vector Group) number
“
0
”.
The system would measure and display a phase displacement of 42
.
The engineer would then adjust the phase displacement (Vector Group) number selection from a
“0” to a”
1
”
(
“1” indicates a
30
shift). The resultant reading from the Ratiometer and T-Rex
would then be 12.0
and be a more accurate phase result.
Rotation convention and nomenclature:
The convention of positive (+) Rotation and negative (-) Rotation is predetermined by the
software and the customers nomenclature.
All TR-Spy and Mark II systems dispatched prior to May 2002 are sent with the following
convention: A Transformer with the following configuration D-Y 1 would have a (+) Positive 30º
result. And a transformer with a configuration of D-Y 11 would have a (-) Negative 30º result.
The reverse convention (D-Y 1 (-) negative 30º & D-Y 11 (+) 30º positive) can be achieved by
requesting a software change for the TR-Spy Mark II and/or TR-Spy from RaytechUSA;
Tel. 888 484 3779. Please indicate serial number upon requesting.
All systems with firmware revision 2.23 and higher have the following selection included in the
software menu: Press “
Setup
” Select “
TRex Phase angle
” Select “
is Positive
” or “
is Negative
”
