IntermediateTopic 52 of 106Electrical Engineering
Transformer efficiency and losses
Copper and core losses reduce efficiency; regulation describes voltage drop under load.
In depth
Losses: copper (I²R, varying with load) and core (hysteresis + eddy, constant). Efficiency η=P_out/(P_out+P_cu+P_core), maximum when copper equals core losses. Voltage regulation is the change from no-load to full-load voltage. Tests: open-circuit and short-circuit.
Key points
- Large units reach 99%
- Cooling by oil and fans
- Tap changers regulate voltage
ExampleA 100 kVA unit with 1 kW core and 1.5 kW copper loss is about 97.6% efficient.
What is Transformer efficiency and losses?
Copper and core losses reduce efficiency; regulation describes voltage drop under load.
Why is it important to understand transformer efficiency and losses?
Losses set the efficiency of transformers and determine how much heat they produce, which is central to their rating and cooling.
What are the two main losses in a transformer?
Copper loss from winding resistance, which depends on current squared, and core loss from hysteresis and eddy currents, which depends on voltage and frequency.
What does voltage regulation measure?
The change in secondary voltage from no-load to full load, expressed as a percentage of the full-load voltage.
How is Transformer efficiency and losses used in practice?
Typical applications include choosing a distribution transformer with low no-load loss for a rural feeder, estimating the efficiency of a power supply transformer at full load and checking the voltage regulation of a long feeder under load.
What should I learn before Transformer efficiency and losses?
Study "Transformers" first (topic 51 of 106 in Electrical Engineering). It covers the groundwork this topic builds on.
What are the key points of Transformer efficiency and losses?
Large units reach 99%. Cooling by oil and fans. Tap changers regulate voltage.
Can you give an example of Transformer efficiency and losses?
A 100 kVA unit with 1 kW core and 1.5 kW copper loss is about 97.6% efficient.
What comes after Transformer efficiency and losses?
The next topic is "Three-phase systems", which builds directly on this one.
How difficult is Transformer efficiency and losses?
It is classed as Intermediate in Electrical Engineering (topic 52 of 106). It is an intermediate topic. Work through the beginner topics in Electrical Engineering first.