Measurement Setup; Connecting Test Cables To Transformer Terminals - Raytech mini-ATOS Instruction Manual

5 Measurement Setup

5.1 Connecting Test Cables to Transformer Terminals

This chapter explains the measurement setup of power transformers and auto transformers.
Connect the mini-ATOS to the test object terminals with the labelled test leads by using the
connection guides according to Table 3 or Table 4.
When you want to perform a measurement in which tertiary winding is involved (e.g., Turns ratio
between primary and tertiary), you have to connect the mini-ATOS X Cables to the tertiary side.
Because of safety, it is not recommended to perform tests between secondary and tertiary. The
voltage may transform to a very dangerous level at the primary side during the measurements.
Check the nameplate information of the transformer. If the nameplate is missing it is still possible to
test the transformer by a trial-and-error method. The mini-ATOS test set is designed to detect
errors in transformer hook-ups. Contact Raytech Service & Support department if you need
assistance.
WARNING!
It is not recommended to test between secondary and tertiary sides!
The voltage may transform to a very dangerous level at the primary
side during the measurements.
Table 5: Test cables connection guide for a single-phase power transformer and auto transformer
Voltage Level
Primary
Secondary
Tertiary
1
Dot can be a letter. For example: 1U1
90297-0.24 Instruction Manual mini-ATOS
mini-ATOS
Test Cable
Label
H1
H2
X1
X2
X1
X2
Preliminary
Transformer Naming Scheme
IEEE IEC
1
H1 1.1
H2 1.2
X1 2.1
X2 2.2
Y1 3.1
Y2 3.2
ABCN
U1 A1
U2 A2
u1 a1
u2 a2
3U1 3A1
3U2 3A2
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