Page 89 - Electric Machinery Fundamentals
P. 89
CHAPTER
2
TRANSFORMERS
(
OBJECTIVES
Understand the purpose of a transformer in a power system.
Know the voltage, current, and impedance relationships across the windings
of an ideal transformer.
Understand how real transformers approximate the operation of an ideal
transformer.
Be able to explain how copper losses, leakage flux, hysteresis, and eddy cur-
rents are modeled in transformer equivalent circuits.
Use a transformer equivalent circuit to find the voltage and current transfor-
mations across a transformer.
Be able to calculate the losses and efficiency of a transformer.
Be able to derive the equivalent circuit of a transformer from measurements.
Understand the per-unit system of measurements.
Be able to calculate the voltage regulation of a transformer.
Understand the autotransformer.
Understand three-phase transformers, including special cases where only two
transformers are used.
Understand transformer ratings.
Understand instrument transformers-potential transformers and current
transformers.
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