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LABORATORY ACTIVITY NO. 5
THREE PHASE TRANSFORMER – DELTA TO DELTA AND DELTA TO WYE
UNBALANCED LOAD
1.1 Introduction:
Transformers are versatile devices that play a pivotal role in electrical power
systems. Their efficiency and adaptability are greatly influenced by the chosen
configuration, which determines how the primary and secondary windings are
connected.
This experiment explores the impact of changing transformer configurations,
specifically transitioning between Delta to Wye and Delta to Delta configurations.
1.2 Objectives:

To investigate the impact of changing transformer configurations,
specifically transitioning between Delta to Wye and Delta to Delta
configurations.
2.1. Materials:

electrical AC machines and electrical apparatus and devices laboratory
trainer

millimeter

tungsten light bulb [6V (3pcs), 3.8V (3 pcs)]

three-phase power supply
2.2. Procedures:
1. DELTA TO WYE CONFIGURATION CHANGE

Connect the transformer in Delta configuration initially.

Change the configuration to Wye and record the primary and
secondary voltages and currents.

Discuss the impact on voltage and current distribution.
Figure 1. Schematic Diagram of Delta-Wye Connection
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2. DELTA-DELTA CONFIGURATION CHANGE

Connect the transformer in Delta configuration initially.

Change the configuration to Delta - Delta and record the primary
and secondary voltages and currents.

Discuss the impact on voltage and current distribution.
Figure 2. Schematic Diagram of Delta-Delta Connection
3.1. Results and Discussion:
For easier analyzation of the obtained readings and values, record the gathered
data in the tables presented below.
Table 1. Summary of Voltage Results
LOAD
VPRIMARY (V)
AB
BC
AC
VSECONDARY (V)
AB
BC
AC
Delta-Wye
(6V-3.8V-6V)
Delta-Delta
(6V-3.8V-6V)
Table 2. Summary of Current Results
LOAD
IPRIMARY (A)
A
B
C
ISECONDARY (A)
A
B
C
APPARENT
POWER (S)
Delta-Wye
(6V-3.8V-6V)
Delta-Delta
(6V-3.8V-6V)
Present the observed trends, analyze the relationships between the relevant
factors or parameters, and discuss any notable findings from the experiment.